The 337 you list as Blizzard is not. It's a plain fan engine (single)

292, 300, 335, 340 are single. 250 probably is single but not going there without printed evidence.

294, 305, 338 are Twin

Your RPM assumptions are only valid for the singles. Twins have a higher / wider range of RPM

 

The 337 you list as Blizzard is not. It's a plain fan engine (single)

292, 300, 335, 340 are single. 250 probably is single but not going there without printed evidence.

294, 305, 338 are Twin

Your RPM assumptions are only valid for the singles. Twins have a higher / wider range of RPM

Yes, that 337 Blizzard was a test to see if People were paying attention. This isn't a complete list of Rotax's Timing, I just copied and pasted what Info he had. I have since sorted his list by Direct Timing. I was looking at that TNT Spec's page at: http://www.reproductionvintageparts.com/bob/index.html

and they show a 1974 300 TNT as a Twin, I see below it also says Type 300T is there two Type 300's then?

I knew there was a 250 Single and a 250 Twin but I don't know what Type there called. I wasn't sure his list were by Type or just General CC Size. That 250 is real close to the other 247 so it's probably a Single also. I thought if I could compile a list of other Engines with same Timing I could send it to them.

Yes, I was talking about Singles, not Twins for the Rpms, since this Conversion kit is listed for the 247/250 Singles.

Never had any Old Twins with Points. Do you have any idea How, we may figure out if this same Conversion could be done on a Twin also. I like their idea of not having to rekey the Flywheel. They just Drilled a Single Hole at a Specific Degree and I think Slots would give you a wider range to work on more Engines. I would expect the Standard Single Engines to have different Timing from the TNT's and the Blizzards. Singles with Points the Coils Centerline is roughly at a 45 Degree angle, on the 247/250 Single Conversion they put the CDI Coils Centerline at roughly 0 Degrees if the Coils are level at the Top. Never had or even seen an Old Twin with points to compare them.

On the Singles, the Studs for the Stator Plate are 4mm and the original Slots on the Horse Shoe Stator are like 15 Degrees Wide. Usually, the Case Stator Plate Studs are Centered on the Slots. If these Case Studs Center Lines are placed every 10 Degrees for a 36 Hole Bolt Pattern, you only have a +/- 4-5 Degrees to play with if using Slots.

The 247 Single Direct Timing

0.147-0.167 in. (3.73-4.23 mm)

and the 250 Single Direct Timing

0.150-0.170 in. (3.81-4.31 mm)

are real close. So I wonder if they just picked the Middle of both, 0.157 in. - 0.160 in. and Drilled their Hole at 0.1585 in. Once I get my Rotary Table for my Mill, I will be able to machine my Horse Shoe Stator Plate and I now have a 247 to test it on. Going down to Branson, MO for daughters Spring Break in March, so I will be stopping at Grizzly Tools in Springfield, MO to look at their Rotary Tables.

If it works on the 250 Single it should also work on the 300 Single since they show same Timing.

 

Yes, I was talking about Singles, not Twins for the Rpms, since this Conversion kit is listed for the 247/250 Singles.

Do you have any idea How, we may figure out if this same Conversion could be done on a Twin also.
I like their idea of not having to rekey the Flywheel. They just Drilled a Single Hole at a Specific Degree and I think Slots would give you a wider range to work on more Engines.

Once I get my Rotary Table for my Mill, I will be able to machine my Horse Shoe Stator Plate and I now have a 247 to test it on.

Obviously you can't use the RMStator conversion on a twin - it is only a single plug wire system. So you must be talking about a Horseshoe CDI conversion.

Finding out if this will work on twins could start with a parts list search. Are Magnet rings the same? Are lighting coils the same? Those will give you an idea if the diameters will be the same.

What you can't do from that is actually measure stator diameter.

As far as using one of your horseshoe stators - you are basing a lot of your assumptions on the RM stator. The problem with that is quite simply - It is not Nippondenso stuff.

RM stators uses an unknown Combo CDI / coil pack. And an unknown stator charge-trigger coil electrically matched to that combo pack.
AND the advance curve of that system is unknown.

ALL OF THAT ultimately dictates where the coil must be in relation to the magnets when the ignition fires.

With all the many many countless hours of CAD drawings, mathematical calculations, 3d printing etc that you have done on this this subject, I am surprised you haven't simply tried it.

Take an hour and prove it to yourself and let us know how hard it will be.

You have several engines and stators.
Bolt a CDI stator on with just one bolt.
Mark the flywheel and case somewhere to show TDC - Pieces of colored tape would work
Spin the engine over with a drill.
Use a timing light to see where it fires in relation to TDC

Then you KNOW how far you have to rotate the stator and mill slots. And if those slots will be accessible around the coils.

 

Obviously you can't use the RMStator conversion on a twin - it is only a single plug wire system. So you must be talking about a Horseshoe CDI conversion.

Finding out if this will work on twins could start with a parts list search. Are Magnet rings the same? Are lighting coils the same? Those will give you an idea if the diameters will be the same.

What you can't do from that is actually measure stator diameter.

As far as using one of your horseshoe stators - you are basing a lot of your assumptions on the RM stator. The problem with that is quite simply - It is not Nippondenso stuff.

RM stators uses an unknown Combo CDI / coil pack. And an unknown stator charge-trigger coil electrically matched to that combo pack.
AND the advance curve of that system is unknown.

ALL OF THAT ultimately dictates where the coil must be in relation to the magnets when the ignition fires.

With all the many many countless hours of CAD drawings, mathematical calculations, 3d printing etc that you have done on this this subject, I am surprised you haven't simply tried it.

Take an hour and prove it to yourself and let us know how hard it will be.

You have several engines and stators.
Bolt a CDI stator on with just one bolt.
Mark the flywheel and case somewhere to show TDC - Pieces of colored tape would work
Spin the engine over with a drill.
Use a timing light to see where it fires in relation to TDC

Then you KNOW how far you have to rotate the stator and mill slots. And if those slots will be accessible around the coils.

The 277F Single, and the 377F/380F, 440F, 503F Twins, all use the same Horse Shoe Nippon Stator, CDI BOX, SINGLE or Dual FIRING COIL depending on Type of Engine used, with a (4) Magnet FLYWHEEL. That is the same Horse Shoe Stator that they are using in this CONVERSION. There is different Brand Name CDI Parts all built to the OEM Spec's, like SPI, etc. Some were Good, some not so Good.

Nobody that I know of has done a Ducati Conversion yet. The 277 was Switched over to Ducati around 2000, but I have not seen one. Ducati and Nippon I think I read once was also Keyed differently. But that's another Thread.

The Original Way to do this Conversion, Points to Nippon CDI was to just take off Points Condenser and Points and Swap out Top Coil with the Yellow CDI Coil off the Horse Type Stator from the 277, 377, 440, 503, and then ReKey the Bosch Points Flywheel. I think this was done for both Singles and 377/377UL, 440/447UL, 503/503UL Twins that had Points also. So it can, and has been done! Steve Beatty of Airscrew did many of them.

I only have (1) loose Horse Shoe Stator I got with a parts 521 and don't know if it's any Good and it has Bigger Coils than than the 277 to 503, it may work, may not. I do have a New Horse Coil used on the 277 - 503 to use with my Drill Jig that I'm waiting for my Rotary Table to make Slots in it versus drilling Holes. I have also acquired a 247 Single to use. They had stopped making the Conversion kit that's Why I even pursue it, then they started making it again at an even lower Price so I stopped pursuing it. If you bought all the Parts New off eBay there was only about $40 difference and wasn't worth my time. If you had more than 2 Engines it probably was account you didn't need to Buy the Flywheel Puller again. I paid $38 for my Flywheel Puller, so a $78 Savings if you do more than one. I didn't have a 247 to test on then either, which I do now.

RMStator for their Points to CDI Conversion is using the same 277F, 380F, 440F, 503F Nippon Type HORSE SHOE STATOR! Is it made by NIPPON probably NOT, there using one of the much cheaper OEM Brands like SPI, etc. Instead of Reindexing the Points Flywheel they are Indexing the whole HORSE SHOE STATOR PLATE to just Work with the Bosch POINTS FLYWHEEL to make it a Bolt on Item that anyone that's smarter than a 8th Grader can do.

You have a Single CDI Plug that comes off the Stator that plugs into one side of the CDI BOX, that other Cable off CDI Box plugs into either a Single Firing Coil for Singles or a Dual Firing Coil for Twins. IF you want Dual Plugs for a Single, just use the Twin Dual Firing Coil. Rotax's use a Wasted Spark Ignition, means it Fires at TDC and it also Fires at BDC.

You can look at NICO's 277 with his Dual Plug Head Conversion. That's HOW he did it. On a UL Engine with Ducati Dual Ignition You have (2) CDI plugs come off the Stator and then use Dual Sets of COIL/CDI Box in a COMBO Unit.

 

I only have (1) loose Horse Shoe Stator I got with a parts 521 and don't know if it's any Good and it has Bigger Coils than than the 277 to 503, it may work, may not. I do have a New Horse Coil used on the 277 - 503 to use with my Drill Jig that I'm waiting for my Rotary Table to make Slots in it versus drilling Holes. I have also acquired a 247 Single to use. They had stopped making the Conversion kit that's Why I even pursue it, then they started making it again at an even lower Price so I stopped pursuing it. If you bought all the Parts New off eBay there was only about $40 difference and wasn't worth my time. If you had more than 2 Engines it probably was account you didn't need to Buy the Flywheel Puller again. I paid $38 for my Flywheel Puller, so a $78 Savings if you do more than one. I didn't have a 247 to test on then either, which I do now.

RMStator for their Points to CDI Conversion is using the same 277F, 380F, 440F, 503F Nippon Type HORSE SHOE STATOR! Is it made by NIPPON probably NOT, there using one of the much cheaper OEM Brands like SPI, etc. Instead of Reindexing the Points Flywheel they are Indexing the whole HORSE SHOE STATOR PLATE to just Work with the Bosch POINTS FLYWHEEL to make it a Bolt on Item that anyone that's smarter than a 8th Grader can do.

You have a Single CDI Plug that comes off the Stator that plugs into one side of the CDI BOX, that other Cable off CDI Box plugs into either a Single Firing Coil for Singles or a Dual Firing Coil for Twins. IF you want Dual Plugs for a Single, just use the Twin Dual Firing Coil. Rotax's use a Wasted Spark Ignition, means it Fires at TDC and it also Fires at BDC.

Well - I know you are smarter than an 8th grader- but just in case, lets do 1st grade pictures
Below are the RM stator parts -

They are NOT the same design as Nipondenso. They are NOT the aftermarket clone replacements you suggest (SPI etc).

FIRST
The CDI box and the external spark plug coil are not separate units - they are one piece.
You can't do what you suggest.......
You have a Single CDI Plug that comes off the Stator that plugs into one side of the CDI BOX, that other Cable off CDI Box plugs into either a Single Firing Coil for Singles or a Dual Firing Coil for Twins. IF you want Dual Plugs for a Single, just use the Twin Dual Firing Coil..

Please tell us how YOU would do a two spark plug arrangement with the RMstator design.

SECOND
The trigger coil on the RMStator is NOT two coils like a Nippondenso - high speed and low speed. It is a single coil. That indicates a much different timing curve is probably used.

Example - Points usually run about 25 degrees when fully advanced -the Nippondenso CDI runs about 19 degrees.

What full advance did RMstator use? 25 like the points stator it was replacing or 19 like a normal Nippon CDI?

More important what would you want YOUR engine to be?

THEREFORE
To my original point - You can't ASSUME that a true Nippondenso/Rotax stator can be positioned exactly the same as an RMstator unit.

IT HAS TO BE TESTED - and since you only have one to play with ... maybe you should try my test procedure before you start milling/drilling away.

I'm not an expert machinist like you- but I'm pretty sure that once the material is milled or drilled away - it's really hard to change your mind and put it back.

Just the humble opinion of an 8th grader......

 

Well - I know you are smarter than an 8th grader- but just in case, lets do 1st grade pictures
Below are the RM stator parts -

They are NOT the same design as Nipondenso. They are NOT the aftermarket clone replacements you suggest (SPI etc).

FIRST
The CDI box and the external spark plug coil are not separate units - they are one piece.
You can't do what you suggest.......
You have a Single CDI Plug that comes off the Stator that plugs into one side of the CDI BOX, that other Cable off CDI Box plugs into either a Single Firing Coil for Singles or a Dual Firing Coil for Twins. IF you want Dual Plugs for a Single, just use the Twin Dual Firing Coil..

Please tell us how YOU would do a two spark plug arrangement with the RMstator design.

==> First this Thread is about Converting Rotax Singles, not Twins. As you said, different Engines have different Timing Requirements, that's WHY I said Slots would have been a better Choice to use, since that would allow it to be used on more Engines. When I first stumbled on this CDI Conversion many years ago now, they were using a different CDI Box Setup, they have stopped Production and started it at lest twice that I know of, and Yes, looking at their current CDI Box in your photo, that is a Combo CDI/Coil Single Firing Unit of unknown origin, it looks to be off one of the newer ATV's or Scooters. But Yes, to Answer your Question, How to, for a Twin would be to either Swap the Combo Single Firing Unit out with same unknown Brand to us, with a Dual Firing Combo Unit, or use a WYE CABLE and use (2) of the unknown to us, Single Firing Combo Units. It fires at TDC and BDC, a Wasted Spark Ignition. Like I said, if you wanted Dual Plugs on a Single like Niko did on his 277, just use the Dual Firing Combo Unit. The Principal is the same Combo Unit COIL/CDI or seperate CDI Box and Coil. I prefer the Separate Setup, first because there cheaper, 2nd if you lose one or the other it's also cheaper to replace. <==

SECOND
The trigger coil on the RMStator is NOT two coils like a Nippondenso - high speed and low speed. It is a single coil. That indicates a much different timing curve is probably used.

Example - Points usually run about 25 degrees when fully advanced -the Nippondenso CDI runs about 19 degrees.

What full advance did RMstator use? 25 like the points stator it was replacing or 19 like a normal Nippon CDI?

More important what would you want YOUR engine to be?

THEREFORE
To my original point - You can't ASSUME that a true Nippondenso/Rotax stator can be positioned exactly the same as an RMstator unit.

==> First, RMstator doesn't sell the individual kit parts to build your own kit, so IF, your going to do something similar, your going to use what I said was the easiest to use, the Nippon Denso CDI setup that was made for Rotax 277, 377, 440, 503's! The one thing that is a Constant, is the Stator, it's SIZE, and LOCATION of the CDI COIls doesn't change! Those STATOR COILS have to be in the RIGHT POSITION with those (4) MAGNETS on the FLYWHEEL to FIRE. With Slots, you can Rotate the Plate +/- a few Degrees. IF, this works on the 247/250 Singles which show different Timing but real Close, they probably picked the middle of them. The 247 (0.147-0.167 in.) and 250 (0.150-0.170 in.) so with a Variance Range of 0.147" to .170" middle of the road would be 0.0115" .

IF, TDC = 0 Degrees, You ought to be able to figure your STATOR PLATE Circumference, let's just say for Example I don't have it close by me, Diameter 8" x 3.14(PI) = 25.12"(Circumference) / 360 = 0.0697777777777778" per (1) Degree for this Example. So if Nippon Denso CDI is 16 Degrees it would be 16 x 0.0697777777777778" = 1.116444444444444" of ZERO Degrees. But if the Points are Keyed at 20 Degrees, I would think you would need to use the same. By using just a HOLE like they did, you have to be pretty precise on where you Drill that Hole. On all of these Rotax's you only have a .020" VARIANCE in TIMING. The NIPPON CDI STATOR PLATE HOLE SLOT is 15 Degrees which is close to 15mm WIDE SIDE to SIDE. The STUDS are 4mm OD, so you loose 2mm each side moving it Side to Side = 4mm off that 15mm to have 11 Degrees roughly to Play with, IF, you use a Slot vs using a Hole. You only have (1) CASE BOLT PATTERN that doesn't change and only (3) CASE STUDS to Locate the STATOR PLATE on that are Equally SPACED. In this case, it's based on a (36) Hole Bolt Bolt Pattern, which 360/36 = 10 Degrees between Stud Center Lines. For Clearance Reasons, to put the Nuts on the Studs you only have one way that works and that is in the UP POSITION as they did. IF, you made a new Stator Plate, it could be Positioned Down, since it Fires at both TDC & BDC. Is there more than one POSITION, YES. BUT, YOU only have (3) CASE STUDS to MOUNT THAT SATOR PLATE and SPACE on that STATOR PLATE to WORK with for the Nuts! Since your using a known Nippon Denso CDI System that Works, it's figuring out how to mount it so it FIRES at the CORRECT TIMING POSITION. Yes, Nippon Denso has (2) Ignition Curves, that's WHY they Idle better than Ducati which only has (1). Since almost NOBODY in the World has a Blizzard Single, and probably very few People today even have a TNT Single, the Majority of People on here have just a Standard 247, 292, 299/300, 318/320, 335 Single which I think the Points version is keyed at 20 Degrees for them. We are TALKING THOUSANDTHS of an INCH in movement for these different Singles Timing. This Nippon Denso Conversion has been done the Old Way by just Re-Indexing the Points Flywheel and using the Yellow CDI Coil many THOUSANDS of Times by the big Ultralight Dealers, so is proven. I think this New Way by just using the whole Horse Shoe Stator is a lot easier if doing your own setup.

You can't Machine a Precision Slot on a Radius without a Rotary Table or make a Special JIG. Does it have to be a Precision Milled Slot, probably not, but I don't like doing something half assed. Like I said, I didn't have a 247 to test it on at the time so I put it on the shelf till I get my Rotary Table. They said it didn't work on my 335 at the time I inquired. I do have a Used Horse Shoe Stator I got with a 583 parts motor, and I also bought a New one off eBay. Caltric Brand off eBay are cheap $39 for Seadoo's. you just have pick what Connectors you want to use.

The Drilling and Milling doesn't affect it from being used as originally designed. <==

IT HAS TO BE TESTED - and since you only have one to play with ... maybe you should try my test procedure before you start milling/drilling away.

I'm not an expert machinist like you- but I'm pretty sure that once the material is milled or drilled away - it's really hard to change your mind and put it back.

Just the humble opinion of an 8th grader......

 

What would be nice is to figure out how to use the Cheap Scooter and ATV CDI Ignition, some is Programable $44 for all of this. GY6 $50. The GY6 Flywheel is Smaller than the Bosch Points Flywheel, so you might be able to take out the Bosch Magnets and jury rig GY6 Flywheel inside it. Dealing with the different Tapers and in/out Spacing is the problem I see.

 

Programable CDI.

 

You should e-mail or call and talk to Mike at RM Stator - they are good to deal with. If you could figure if there would be enough demand for what you want - they might just develop it. Especially if it could be done by modifying some of there products that are already produced - it may be worthwhile. I am sure a lot of guys would like to have a CDI system on there old singles.

 

You should e-mail or call and talk to Mike at RM Stator - they are good to deal with. If you could figure if there would be enough demand for what you want - they might just develop it. Especially if it could be done by modifying some of there products that are already produced - it may be worthwhile. I am sure a lot of guys would like to have a CDI system on there old singles.

I did a long time ago via e-mail, they said they were working on it for some other Rotax Single Engines. I guess, it's not at the Top of their list of things to do. People want CDI, it's just they don't want to Pay much for it. The Scooter/ATV stuff could keep Price down. You only have about (6) common Families of Points Singles, 247/250, 277, 292, 299/300, 318/320, 335/340 and their TNT versions. There is very few of the Blizzard Singles out there, or any Info. There were a couple smaller Singles out, but I have only seen photo's of them. With a Variance of .140" to .180" = .040" for the list I showed. With Slots, instead of Holes you could probably cover them all. Once I get my Rotary Table I'll machine this Stator and put it on my 247 first to make sure it works ok on it, then I'll try it on my other Singles. Only one I don't have now is a 318/320 and those early Smaller ones below the 247.

 

GY6

 

==> First this Thread is about Converting Rotax Singles, not Twins.

In Post #3 of this thread YOU asked -
Do you have any idea How, we may figure out if this same Conversion could be done on a Twin also.

So YOU ALONE changed this thread to one which included twin cylinder engines.

My answer in Post #4 was simply a response to your question. The RMStator Elan single won't work on a twin. That is a fact. I then gave you some of the ideas you also asked for to determine the possibilities.

You then stated in Post #5 above .........
When I first stumbled on this CDI Conversion many years ago now, they were using a different CDI Box Setup, they have stopped Production and started it at least twice that I know of, and Yes, looking at their current CDI Box in your photo, that is a Combo CDI/Coil Single Firing Unit of unknown origin.

I am surprised you think this is a recent development. In Sept. of last year (2017) - you posted about the RMStator Elan Kit and included links to the installation video and instructions PDF. My picture is the exact same one you posted in that thread. http://www.dootalk.com/forums/topic/1106497-cdi-plate-for-conversion-of-old-singles/?hl=rmstator#entry19975986

By studying the documents you linked to back then - I knew it would not work on a twin.

Sorry for thinking that you understood what you were posting about just 5 months ago.
Even with the all the pictures and instructions you posted - In the last post of the thread (#10) YOU still suggested that all a member had to do was buy a different external coil for his 250 twin.
"They don't list a conversion kit specific for the 250 Twin, but you ought to be able to substitute a dual firing coil for the single firing coil.
This Type of CDI Ignition is called a Wasted Spark Ignition, that means it fires at TDC and at BDC! So it should work for a Single and a Twin if you use the right coil (377F, 440F, 503F)."

I hope he didn't waste any money trying to make it work ......

 

Speaking of bad/misleading data .....

In October of last year you answered another post by a member concerning the Rmstator Elan conversion.
"It looks like they have lowered their Kit price also, was $299, now $199, which $199 is a very fair price for all New parts. You still need to buy a CDI Coil $43 on eBay."

Seems odd you should have posted that advice.

Just a month earlier you posted the pictures and instructions that clearly showed NO additional coil was needed when using their conversion kit.

It would seem you should go back and correct both those posts, since you now know that false and misleading information was distributed.
I am sure you would not want anybody searching these old posts to make any needless purchases based on your incorrect content.

These are the two posts that should be corrected in reference to the RMSTATOR Elan conversion.

No Need for additional external coil
http://www.dootalk.com/forums/topic/1448834-elan-cdi/

Cannot be used for Twins by substituting a twin coil (377F, 440F, 503F)
http://www.dootalk.com/forums/topic/1106497-cdi-plate-for-conversion-of-old-singles/

 

This Nippon Denso Conversion has been done the Old Way by just Re-Indexing the Points Flywheel and using the Yellow CDI Coil many THOUSANDS of Times by the big Ultralight Dealers, so is proven. I think this New Way by just using the whole Horse Shoe Stator is a lot easier if doing your own setup.

You can't Machine a Precision Slot on a Radius without a Rotary Table or make a Special JIG. Does it have to be a Precision Milled Slot, probably not, but I don't like doing something half assed. Like I said, I didn't have a 247 to test it on at the time so I put it on the shelf till I get my Rotary Table. They said it didn't work on my 335 at the time I inquired. I do have a Used Horse Shoe Stator I got with a 583 parts motor, and I also bought a New one off eBay. Caltric Brand off eBay are cheap $39 for Seadoo's. you just have pick what Connectors you want to use.

The Drilling and Milling doesn't affect it from being used as originally designed. <==

So...........
You have been pursuing this CDI conversion process for at least 3 years
http://www.dootalk.com/forums/topic/1106497-cdi-plate-for-conversion-of-old-singles/

After all that- your advice to the members at this point is that they buy a mill and rotary table, then proceed to precision mill their stators? (RMstator or Nippon)

How is that any easier / less expensive than the PROVEN ultralight method of repositioning the flywheel that requires nothing more than hand tools that virtually every snowmobile mechanic has at home today?????

You yourself posted that the cost of the Nippon style parts were comparable (if not less expensive) than the RMstator Elan conversion, even at their new lowered price.

Wondering why you have not posted the procedure for this proven method?
I am sure someone with your machining skills can cut a simple key way in a flywheel with a mill. Perhaps you can make a youtube video for us??

Based on view numbers of CDI conversion posts - Seems like a lot of Rotax Doo singles (and maybe twins) could have been converted to CDI by members here over the last three years had this method been revealed in detail.

Maybe not posting the details of this proven conversion process is a marketing strategy? You know, keep people interested while waiting until you make whatever kit you are planning available to the public? Apple does that a lot to raise prices.

If so, do you have a target date when your kit will be available?

 

In Post #3 of this thread YOU asked -
Do you have any idea How, we may figure out if this same Conversion could be done on a Twin also.

So YOU ALONE changed this thread to one which included twin cylinder engines.

My answer in Post #4 was a response to your question. The RMStator Elan single won't work on a twin. That is a fact. I then gave you some of the ideas you asked for to determine the possibilities.

You then stated in Post #5 above .........
When I first stumbled on this CDI Conversion many years ago now, they were using a different CDI Box Setup, they have stopped Production and started it at least twice that I know of, and Yes, looking at their current CDI Box in your photo, that is a Combo CDI/Coil Single Firing Unit of unknown origin.

I am surprised you think this is a recent development. In Sept. of last year (2017) - you posted about the RMStator Elan Kit and included links to the installation video and instructions PDF. My picture is the exact same one you posted in that thread. http://www.dootalk.com/forums/topic/1106497-cdi-plate-for-conversion-of-old-singles/?hl=rmstator#entry19975986

By studying the documents you linked to back then - I knew it would not work on a twin.

Sorry for thinking that you understood what you were posting about just 5 months ago.
Even with the all the pictures and instructions you posted - YOU still suggested that all a member had to do was buy a different external coil for his 250 twin.
They don't list a conversion kit specific for the 250 Twin, but you ought to be able to substitute a dual firing coil for the single firing coil.
This Type of CDI Ignition is called a Wasted Spark Ignition, that means it fires at TDC and at BDC! So it should work for a Single and a Twin if you use the right coil (377F, 440F, 503F).

I hope he didn't waste any money trying to make it work ......

:deadhorse:

 

On the Singles, the Studs for the Stator Plate are 4mm and the original Slots on the Horse Shoe Stator are like 15 Degrees Wide. Usually, the Case Stator Plate Studs are Centered on the Slots. If these Case Studs Center Lines are placed every 10 Degrees for a 36 Hole Bolt Pattern, you only have a +/- 4-5 Degrees to play with if using Slots.

The 247 Single Direct Timing
0.147-0.167 in. (3.73-4.23 mm)
and the 250 Single Direct Timing
0.150-0.170 in. (3.81-4.31 mm)

are real close. So I wonder if they just picked the Middle of both, 0.157 in. - 0.160 in. and Drilled their Hole at 0.1585 in. Once I get my Rotary Table for my Mill, I will be able to machine my Horse Shoe Stator Plate and I now have a 247 to test it on. Going down to Branson, MO for daughters Spring Break in March, so I will be stopping at Grizzly Tools in Springfield, MO to look at their Rotary Tables.

If it works on the 250 Single it should also work on the 300 Single since they show same Timing.

Not sure if you tumbled to this yet.

But the main reason that you have two groups of timing specs for the singles is their stroke.

Changed the chart to show timing in DEGREES not in/mm

You can plainly see that a CDI conversion wth a 25ish degree advance would cover all the models.

 

Sightation it almost seems you're implying that RotaxFlyer is all talk and no action....nah, that can't be. I give you credit, you're a far more patient man than me.

 

Not sure if you tumbled to this yet.

But the main reason that you have two groups of timing specs for the singles is their stroke.

Changed the chart to show timing in DEGREES not in/mm

You can plainly see that a CDI conversion wth a 25ish degree advance would cover all the models.

No, I didn't, but Thanks for converting them. I thought it had more to do with some engines rated at different 5500rpms, 6500rpms, Blizzards ????rpms. With 66mm Stroke you have a variance of 0.140" to 0.170" and the 70mm Stroke 0.160" to 0.180". Like I said, maybe use the middle of the Road 0.140" to 0.180" = 0.160" and if you look at it in Degree's, your doing the same thing. 23.82 to 26.3 = 25.06 Degree's.

But we don't know what Degree they're using on their Kit. They Told me it wouldn't work on my 1972 335 Oly Engine when I inquired a few years ago. We don't have a Timing Mark on the Horse Shoe Stator to go from. The only thing we have is their Photo's and them saying the Yellow Coils are level at the Top. The easiest way would be to just get one of their kits and see where they put their Hole, and then try it on a 247/250 to see if it works Good first, then try it on different Single engines, and make any changes if needed by making a Slot.

A Slot from 20-30 Degrees would give you a +/- to work with for any Single. The Stator Plate Studs are 4mm OD so you lose a few degrees on each end of the Slot. Factory CDI Stator Plate Slots were 15 Degrees Wide, if I remember right. So probably 22-28 Degrees.

When I first found that site, I asked them if it worked on other Singles and they said No, but they were working on others. Then a few years later, I got my first Old Points Single, a 1972 335, I talked to them again to see if it would work yet, and they said No, but they are working on it.

Here is the response I got a 3/6/2018, after I sent them that list of Rotax Engine Timing Spec's I posted.

New message from: rmstatorinc (57,515)

Hi,

The kit should be available again within a month or so, sorry I don't have an exact date. We have not tested the kit on other models, but you are most likely correct. If the backing plate is the same diameter, slotting the holes will probably give you enough timing adjustment. We can't guarantee or warranty the kit for a non-listed model though.

Thanks!

Kind regards,
Evan
RM STATOR

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Reply

Your previous message​

Hello:

Does this work on both the 247(69mm x 66mm) and 250(69mm x66mm) Singles? I was looking at some Timing Info I found on a web page that listed some Singles and Twins made from 1970-79. I sorted the list, in excel by Direct Timing. The ones in RED have the same Timing. The 250 and 300 Singles are really close to the ones in RED. I would think if you used Slots instead of a Hole, it could maybe work on more Singles. I see your Sold out, any idea when you will have more?

 

sightation, on 03 Mar 2018 - 06:17 AM, said:

In Post #3 of this thread YOU asked -
Do you have any idea How, we may figure out if this same Conversion could be done on a Twin also.

So YOU ALONE changed this thread to one which included twin cylinder engines.

==> Since I was talking of making your own kit out of Nippon CDI parts off ebay, maybe I didn't make that Clear enough for you and I have never had a Twin with Points, that's Why I asked! Do I think it can be done Yes, account it has been done years ago on 377's, 440, 503, etc. The Singles Points Coils are Angled to the Right of TDC about 45 Degrees, the Twins, I recently found a photo, show them Angled to the Left of TDC about 45 Degrees.

Since I don't have one to experiment with I'll let You the Expert figure it out for the Team. Give you something to do, besides "edit for bad language"ing all the Time on here. Since the CDI Coil has to be in the right postion, I would bet for the Twin, it would still be Mount Up like the Single, but maybe turned a little more the Timing. <==

My answer in Post #4 was a response to your question. The RMStator Elan single won't work on a twin. That is a fact. I then gave you some of the ideas you asked for to determine the possibilities.

You then stated in Post #5 above .........
When I first stumbled on this CDI Conversion many years ago now, they were using a different CDI Box Setup, they have stopped Production and started it at least twice that I know of, and Yes, looking at their current CDI Box in your photo, that is a Combo CDI/Coil Single Firing Unit of unknown origin.

I am surprised you think this is a recent development. In Sept. of last year (2017) - you posted about the RMStator Elan Kit and included links to the installation video and instructions PDF. My picture is the exact same one you posted in that thread. http://www.dootalk.c...r#entry19975986

==> Yes, I didn't look close at their New Photo in 2017 the 2nd time I found their Ad, the first time before that, when I saw their Ad, it looked like a Nippon Style Box which is bigger than what they are using now. The principle is the same as the Single, change out the Single CDI/Coil Combo unit for a Twin CDI/Coil Combo Unit. Since they don't Sell a Twin Kit or a Dual Firing CDI/COIL Combo, it's pretty obvious you need to get your own Parts, which I have said, the Nippon CDI 277, 377, 440, 503, Horse Shoe Stator stuff is the easiest to use. <==

By studying the documents you linked to back then - I knew it would not work on a twin.

==> It should, if you swap out the Single Firing CDI/COIL Combo with a Dual Firing CDI/Coil and Adjust for the difference in Single/Twin Timing. As we know now for the Singles, 25 Degrees is the middle of the Road, what is the Twins middle of the Road Timing? Another project for You to work on for the Team. <===

Sorry for thinking that you understood what you were posting about just 5 months ago.
Even with the all the pictures and instructions you posted - YOU still suggested that all a member had to do was buy a different external coil for his 250 twin.
They don't list a conversion kit specific for the 250 Twin, but you ought to be able to substitute a dual firing coil for the single firing coil.
This Type of CDI Ignition is called a Wasted Spark Ignition, that means it fires at TDC and at BDC! So it should work for a Single and a Twin if you use the right coil (377F, 440F, 503F).

I hope he didn't waste any money trying to make it work ......

===> I'm sure if he contacted them about buying that CDI Dual Firing Coil they would have Inform him of the difference of their kit parts, if he had used the Nippon CDI like I have suggested all along, he would have been ok, once he figured out the Timing isssue. What's Sad, is You could have simply pointed that mistake out to Help, but yet you did nothing as usual, but complain and "edit for bad language" later on here. <===

 

So...........
You have been pursuing this CDI conversion process for at least 3 years
http://www.dootalk.com/forums/topic/1106497-cdi-plate-for-conversion-of-old-singles/

After all that- your advice to the members at this point is that they buy a mill and rotary table, then proceed to precision mill their stators? (RMstator or Nippon)

How is that any easier / less expensive than the PROVEN ultralight method of repositioning the flywheel that requires nothing more than hand tools that virtually every snowmobile mechanic has at home today?????

You yourself posted that the cost of the Nippon style parts were comparable (if not less expensive) than the RMstator Elan conversion, even at their new lowered price.

Wondering why you have not posted the procedure for this proven method?
I am sure someone with your machining skills can cut a simple key way in a flywheel with a mill. Perhaps you can make a youtube video for us??

Based on view numbers of CDI conversion posts - Seems like a lot of Rotax Doo singles (and maybe twins) could have been converted to CDI by members here over the last three years had this method been revealed in detail.

Maybe not posting the details of this proven conversion process is a marketing strategy? You know, keep people interested while waiting until you make whatever kit you are planning available to the public? Apple does that a lot to raise prices.

If so, do you have a target date when your kit will be available?

Yes, my first Rotax Single I started buying, piece by piece at the time off ebay to collect all the Core Parts, it was a 1981 277 Points engine. I wanted to convert it to CDI, but I eventually, discovered in my research the Case came with (2) different Bolt Patterns, one for Points Stator and one for CDI Stator. The 277 has an Odd Ball Taper for the Flywheel, it's keyed at TDC, whereas the other Old Singles are not. I had trouble finding that 277 Points Flywheel for a long time and had went and bought a newer CDI Crank & Flywheel for it, so I didn't start to pursue the CDI Conversion again till I got my first 335. Since I didn't have a Sled to put the motor in, it wasn't at the Top of the to Do List either.

You don't need a Rotary Table, You can just Drill a Single Hole at the right Degree like they did. My Goal was to make it work for all the Old Singles by using Slots. I recently got a bunch of Old Singles to work with, a 247, 299, and some more 335's, but I have been working on other projects.

Today 3/7/2018 their kit is listed for $199, when I first seen it listed, it was $299. The Nippon CDI Stuff on eBay last time I priced it out was around $140 if you shopped around. So was their web page back then a Type O, or did they lower their Price, I don't know? If your only doing one engine, I would just buy their kit. I now have a 247, a 2nd 277, a 299, and (4) 335's and (1) 340 TNT that I want CDI for.

I did post the basic Info for the Old Way Conversion, I never new what Degree the Flywheel needed Rekeyed at, since I only had the 277 at the time, and I didn't know if all the Singles used the same Degree or not, since I didn't have any of them to even look at for most of the time.

I have No Interest in Making or Selling a Kit. I have given any Info I have found on the subject freely. I can't post CAD Format Files here to my Drill JIG, which is Not Proven yet, or the STL file to have it 3D Printed. Once I have it Proven, anyone who wants it can have it. RMS doesn't really seem to keen on making these to fit all the Singles, maybe they don't have a Rotary Table either.

If, you could convert the Twins Timing to Degrees, and since the Singles Points Coils Pointed to the Right at 45 Degrees and the Twins Points Coils Pointed to the Left at 45 Degrees in the Photo I saw, if the Singles Middle of the Road is 25 Degrees, it would be interesting to see what the Twins work out to. How many different Strokes does those Twins listed have, was any of them listed, Triples?

But Thanks for contributing here towards the subject, your the first in 3 years.

 

Speaking of bad/misleading data .....

In October of last year you answered another post by a member concerning the Rmstator Elan conversion.
"It looks like they have lowered their Kit price also, was $299, now $199, which $199 is a very fair price for all New parts. You still need to buy a CDI Coil $43 on eBay."

Seems odd you should have posted that advice.

Just a month earlier you posted the pictures and instructions that clearly showed NO additional coil was needed when using their conversion kit.

It would seem you should go back and correct both those posts, since you now know that false and misleading information was distributed.
I am sure you would not want anybody searching these old posts to make any needless purchases based on your incorrect content.

These are the two posts that should be corrected in reference to the RMSTATOR Elan conversion.

No Need for additional external coil
http://www.dootalk.com/forums/topic/1448834-elan-cdi/

Cannot be used for Twins by substituting a twin coil (377F, 440F, 503F)
http://www.dootalk.com/forums/topic/1106497-cdi-plate-for-conversion-of-old-singles/

Not bad if they were still using the Nippon Style CDI Box I saw the first time. They must have switched units and I missed that in the photos. The Principle is the same, if they sell a Dual Firing CDI/COIL Combo Unit to go with that Horse Shoe Stator, which they don't list one on their website. So to make a kit yourself, the only Option is to use the Nippon CDI Stuff. I went back and made the corrections.

 

Not bad if they were still using the Nippon Style CDI Box I saw the first time. They must have switched units and I missed that in the photos. The Principle is the same, if they sell a Dual Firing CDI/COIL Combo Unit to go with that Horse Shoe Stator, which they don't list one on their website. So to make a kit yourself, the only Option is to use the Nippon CDI Stuff. I went back and made the corrections.

Thanks for making the corrections

 

You don't need a Rotary Table, You can just Drill a Single Hole at the right Degree like they did. My Goal was to make it work for all the Old Singles by using Slots. I recently got a bunch of Old Singles to work with, a 247, 299, and some more 335's, but I have been working on other projects.

Yes they could be drilled single hole but that does not allow for adjustment for electrical tolerance. It is nice that you have access to all the stuff you do.

However I and 98.765% of the snowmobile owners of the world will never own a mill or rotary table.

So I took some time today to make a drill / slot guide to be used with simple hand tools when modifying CDI stators for use on point engine conversions.
Using this guide any stator can be slotted with a simple hand drill. Having a Dremel would simplify it too.

Design Goals
Slot Positions ...Same as Rotax Factory
Slot length.....Same as Rotax Factory
Slot width.......Same as Rotax Factory
Accuracy........Same as Rotax Factory
Tolerance.......Same as Rotax Factory

Results
CAD design time.... ..Zero Hours
Manufacturing Time .....1/4 Hour
Cost ................Zero (point engine being converted supplies raw material)

2D CAD file available .... No

 

Yes, my first Rotax Single I started buying, piece by piece at the time off ebay to collect all the Core Parts, it was a 1981 277 Points engine. I wanted to convert it to CDI, but I eventually, discovered in my research the Case came with (2) different Bolt Patterns, one for Points Stator and one for CDI Stator. The 277 has an Odd Ball Taper for the Flywheel, it's keyed at TDC, whereas the other Old Singles are not.

Of course slotting a CDI stator would be easier than keying a flywheel - if that would actually work.

Here is something to consider before you spend time and energy machining a CDI stator as you have suggested you will do with your Nippondenso unit when you get a rotary table.

When Rotax started using CDI's on the 277, 377, 503 engines they used a two hole stator. That is because all the twin cases of that time used two hole points stators.

Since single points stators used three holes - On the 277 they added one 1 extra mounting hole, making 4 total. The added hole is in the upper left quadrant. The second hole used was one of the original holes. Lower Right quadrant

Below is a picture of a 277 case with the extra hole. Yellow arrows for point stator - Red arrows for CDI

NOW ...........
If you line up those common holes on a point stator and a two hole CDI stator you can see the relation between the ignition coils.

Placing the top hole of the point stator where it would be on a 247 type case (around 12 o'clock high) you can clearly see where the CDI coil would be in relation to the case.
It is nowhere near the top of the arc - Where the RMstator coil is. In fact, the end of the coil is pretty close to the mounting hole so no hole could be drilled.

So the question remains - Where does the Nippondenso coil setup need to be to give proper timing?

Using the one hole mount, universal timing test, still seems a prudent idea before any drilling and milling is done on a CDI stator even if only a $34 aftermarket unit.

Sure wish that someone with I dunno, maybe nine Rotax single engines, would take an hour or so and try it just to see how feasible the stator mod would be vs the proven method.

 

I saw a reference to GY6 CDIs. I'm knowledgeable to the DC ones. The timing curve in them would fit these engines perfectly.