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Discussion Starter · #1 ·
I'm not a happy camper ...

Installed Cudney Rings & Pistons on my '03 600HO in the fall for preventative maintenance (sled had 5,000kms and was starting to show degredation in compression.. stalling in reverse, etc.). Put the new pistons/rings in with caged bearings. Put everything back together meticulously - carbs were cleaned, everything hooked up. Started it up and she purred... then I waited for snow. I also dropped the needles in the carbs as per the 'optimizing your 600HO' thread on this board.

And waited ..

And waited...

Snow finally came late January and the sled never ran so good for a few weeks. Pulled both plugs and they were a beautiful golden brown. Gas mileage was way way up compared to before the rebuild, and I was putting it through a slow and careful breakin.

Breakin period over (about 200KMs) I went to Ipone synthetic oil and still never really beat on it hard - use it mostly to ride trails and it purred. darn was the sled running well!

Anyway, take it out Saturday morning for a nice ride on my birthday. Weather was beautifully sunny and cold (-14C) and we went for a short ride. I always warm the sleds up fully before taking them out. My wife and I went for a short ride (about 25mins) and I started to notice a low "growling" sound from the engine -- mild at first so I took it real easy to get it back home but it was growing and I noticed a slight loss in power -- almost sounded like a 4stroke lower growl.

Got it back to the cottage and shut it down. When I fired it back up it had a real hard time idling and at low RPM (around 1,000RPM) would backfire like a son of a gun. I pull out the service manual to go through the troubleshooting list -- tells me it could be fouled plugs or bad gas. Replace the plugs.. no change. Add Iso to the tank and wait 10 mins -- no change. Pull the carbs to clean 'em and there's a bit of frost on the slider of one carb (could that do anything?) but the carbs were good and clean, but i recleaned 'em anyway. Still no change.

Didn't want to take any chances so I put it on the trailer and took it over to Haultain Service (they're an amazing group of guys btw.. family run and they did wonders on my wife's 440F). He ran a compression check on it and told me the bad news -- no compression on the MAG side. She still started first pull but it just ran like SH**.

Wonderful birthday gift. The sled had 500kms on the new pistons/rings.


So he pulls the top end off and says that the mag side was running lean, it was noticeable towards the exhaust side -- worn down to the ring and the ring broke, groove in the cylinder. So I need a new piston and ring for that side and the cylinder replated. Lovely. So much for preventative maintenance.

Here's what's strange -- he said the top end looked great - didn't see anything obvious -- carbs were good and clean (I did just clean 'em but they were spotless when I pulled them apart earlier anyway). He said during the rebuild that to be safe he recommends I replace the seals in the lower end -- at 5,000KMs?? For real? Should I be worried about this already?

You're suggestions / advice would be greatly appreciated. This has totally bummed me out. The good news is he said that if all the parts are in stock he could have me back on the trails for our big planned weekend coming up, but it's going to cost me a grand probably all said and done. Crap.

And do you think Bill will cut me a break on a single piston / ring?? (wishful thinking??!!
)

What do you guys think? Replace the seals? Jet richer from now on? (Would rather be safer and have it run slower than go through this again).

Sorry, can't get pictures. Tried to be as descriptive as possible.

...Bill
 

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Well I don't remeber you calling me for a piston, a cylinder or anything else this weekend as a matter of fact nobody called looking for them, but I can tell you that I am 99% sure that "optimizing your 600HO" was the reason, we have seen that so many times here we have lost track for the most part the optimization does just what happened to yours. -- Bill
 

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nAVEL said:
I'm not a happy camper ...

Installed Cudney Rings & Pistons on my '03 600HO in the fall for preventative maintenance (sled had 5,000kms and was starting to show degredation in compression.. stalling in reverse, etc.). Put the new pistons/rings in with caged bearings. Put everything back together meticulously - carbs were cleaned, everything hooked up. Started it up and she purred... then I waited for snow. I also dropped the needles in the carbs as per the 'optimizing your 600HO' thread on this board.

And waited ..

And waited...

Snow finally came late January and the sled never ran so good for a few weeks. Pulled both plugs and they were a beautiful golden brown. Gas mileage was way way up compared to before the rebuild, and I was putting it through a slow and careful breakin.

Breakin period over (about 200KMs) I went to Ipone synthetic oil and still never really beat on it hard - use it mostly to ride trails and it purred. darn was the sled running well!

Anyway, take it out Saturday morning for a nice ride on my birthday. Weather was beautifully sunny and cold (-14C) and we went for a short ride. I always warm the sleds up fully before taking them out. My wife and I went for a short ride (about 25mins) and I started to notice a low "growling" sound from the engine -- mild at first so I took it real easy to get it back home but it was growing and I noticed a slight loss in power -- almost sounded like a 4stroke lower growl.

Got it back to the cottage and shut it down. When I fired it back up it had a real hard time idling and at low RPM (around 1,000RPM) would backfire like a son of a gun. I pull out the service manual to go through the troubleshooting list -- tells me it could be fouled plugs or bad gas. Replace the plugs.. no change. Add Iso to the tank and wait 10 mins -- no change. Pull the carbs to clean 'em and there's a bit of frost on the slider of one carb (could that do anything?) but the carbs were good and clean, but i recleaned 'em anyway. Still no change.

Didn't want to take any chances so I put it on the trailer and took it over to Haultain Service (they're an amazing group of guys btw.. family run and they did wonders on my wife's 440F). He ran a compression check on it and told me the bad news -- no compression on the MAG side. She still started first pull but it just ran like SH**.

Wonderful birthday gift. The sled had 500kms on the new pistons/rings.


So he pulls the top end off and says that the mag side was running lean, it was noticeable towards the exhaust side -- worn down to the ring and the ring broke, groove in the cylinder. So I need a new piston and ring for that side and the cylinder replated. Lovely. So much for preventative maintenance.

Here's what's strange -- he said the top end looked great - didn't see anything obvious -- carbs were good and clean (I did just clean 'em but they were spotless when I pulled them apart earlier anyway). He said during the rebuild that to be safe he recommends I replace the seals in the lower end -- at 5,000KMs?? For real? Should I be worried about this already?

You're suggestions / advice would be greatly appreciated. This has totally bummed me out. The good news is he said that if all the parts are in stock he could have me back on the trails for our big planned weekend coming up, but it's going to cost me a grand probably all said and done. Crap.

And do you think Bill will cut me a break on a single piston / ring?? (wishful thinking??!!
)

What do you guys think? Replace the seals? Jet richer from now on? (Would rather be safer and have it run slower than go through this again).

Sorry, can't get pictures. Tried to be as descriptive as possible.

...Bill
[snapback]725468[/snapback]​
Q! my god, and it had Cudney pistons and rings!
 

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Discussion Starter · #5 ·
Bill -

Thanks for the reply .. I just called you.

I dropped the needles - and the mechanic who tore into it said there was nothing wrong with the rebuild, everything looked crisp but that it was running hot. So that could be it.

An update - he did say that the seal behind the PTO clutch was starting to come loose - it was about 3/4 out (wasn't spewing grease yet) -- he said it should be replaced, but because only one piston melted down, he still suspects it was in the carbs ...

I'm totally bummed. I'm going to have him replace the seals in the lower end (I've never done a bottom end myself) but I think I'll redo the top end myself. As he quoted me $1490 CAD for everything (ouch... that stings WAY too much right now). Whereas I'm looking at 5 hrs labour (including tear down and seal replacement) and couple hundred in parts for the seal & gasket kit and bearings in the bottom end if I redo the top end myself..

Mind you i still need to pick up new pistons rings and get one cylinder replated. Ugh.

Anyone know a good place to send the cylinder for replating? What would it cost me?

thanks!
Bill
 

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Discussion Starter · #6 ·
Oh. I should add that my thread above is NOT meant to place any kind of blame on Cudney's products - as I still think they're the way to go. The burndown had nothing to do with his excellent pistons or rings (it does show us that nothing is impervious to disastor tho'!)
<sniff>
 

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My sled has been optimized for the last 5000 miles (600ho) and not a problem. I ride in colder temps. most of the time. Doo pistons and chrome rings.
 

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look around this site people are selling used cylinders, I got one from sled parts .com who is a sponser, Also Bill Cudney Went ABOVE AND BEYOND" Helping me out with a recent rebuilt i had to do (pluged main jet along with dusty conditions).
 

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Bill I will call you shortly but to address the above by fd6, if you are an aggressive trail rider hard on and off the throttle burp the throttles instead of steady mid range riding then the suggestions do work well for you but if you are a fairly steady midrange rider then that is when the lean problem happens in the mid range. -- Bill
 

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Discussion Starter · #11 ·
Just spoke with Bill. I gotta see, there truly is nobody in this industry with the class and service that he provides.

Thanks Bill for setting me up!
 
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