Breakdown Part 5- Motor Assembly, Tons of pics... Options

[sleddude5]

Ok, if you access my Breakdown Part 4 Story, there are links to the first three episodes of this saga.

Here in part 5, you will see the motor assembly, from bottom to top.

First things first, and this is the most time consuming thing of the whole motor assembly, all parts must be very clean, as in as spotless as possible. Remember: Cleanliness is next to Gosh-darn-motor-runs-greatliness.

Here's a quick pic of me doing some clean up on the top of the crankcase. Use a brass brush. I like brake cleaner, and a sanding sponge makes quick work of gasket removal, just don't be a crazy, aggressive sanding-machine-man. Clean out all bolt holes. If you can, run a bottoming tap in all bolt holes, then blow them clean with brake cleaner then air. Clean all bolts, or better yet replace them all, threads do stretch.



Here you can see a pic, blurry as it is, of one of the oil feed holes that Greg at Seadooclinic.com drilled into my case to supply oil to the outer bearings. No more isoflex here, eh. Things need to be put together a certain way though to ensure proper oil flow to those bearings.



The outer bearing has a, well, a ring attached to it, and this ring has a gap in it. The outer side of the bearing gets marked exactly at the point where the gap is. Also the case gets marked at the point where the oil feed hole was made. At assembly these two marks need to be lined up to allow oil flow to the bearing.



The PTO end seal gets a mark as well. If you hold the seal in your hand and look at the back side you will see the seal has ridges on the back of it. The seal gets marked at the middle of one of the seal ridge low points. This also allows oil flow to the back of the bearing. So the three marks need to be lined up during assembly. Also in this pic you can see I have all the case bolts set up on a piece of paper, with each bolt in its proper position and numbered as to its order of installation. Set the crank in place in the top crankcase half with the rods hanging down through the top case openings. I set the case on a 4"x 4" to allow room for the rods. Make sure the inner seals are sitting in the grooves properly, as with the outer PTO seal and the outer mag side seal. Apply the case sealant to one half of the case, I use Threebond 1194, and put the bottom case in place over the crankshaft and onto the upper half. I usually give a decent shove down on the case to set the two halves together and then get working on case bolt installation. Once the cases are mated you have 3-5 minutes to get all the bolts torqued down before the sealant sets up. So do not dilly-dally!



Ensure all case bolts are torqued properly. Use two steps to get to the final torque value and be sure to follow the correct torque pattern.



At this point I prelube the all the lower end bearings. Apply two stroke oil to all rod end bearings and case bearings. Here you can see me squirting some lube into a hole drilled by Seadooclinic.com to get some oil to those outer bearings, to ensure they are properly lubed before the motor's first startup.



Here's a pic of the assembled bottom end. At this point make sure to rotate the crankshaft over, maintaining support on the rods so they don't just clank around, and check for freedom of movement in both the forward and reverse direction through 360 degrees of rotation. Also make sure the water pump and oil pump drive gear are rotating freely as the crank goes roundy-roundy, this ensures you have the crank gear mated properly with the gear on the shaft which drives the two pumps.



Do not forget to fill the center cavity where the aforementioned gears are located. Do this by pouring your 2 stroke oil of choice into the oil pump drive gear. The oil will flow through and then fill this void with oil. If you forget this step, you will get about 30 seconds down the trail before that nylon pump gear is stripped by the metal gear on the crank. Then you will have no oil or water flow. That is bad. I then cap off the fitting directly above the oil pump drive gear, which will be hooked to the oil tank on the sled, and install the oil pump. This prevents the oil from draining out. After that I put on the water pump housing.



On to the top end.

I don't have a set of those fancy circlip installers yet, so this is what I do...
...file a groove at the end of each jaw of a set of needle nose pliers. This allows you to get a real good grip on the circlip while installing it.



Here I am installing a circlip into the piston. Do the inside circlip position first and leave the outside position for when the pistons are on the rods.



The next 3 pics are of setting the ring gap. I like to install the ring into the cylinder bore with the ring gap set physically at the position it is going to run after it is permanantly installed. Then, using a piston, set the ring square in the bore by pressing down slightly on it with the piston. Ensure the ring is approximately halfway down the cylinder before measuring. The piston kit you received should tell you what the gap in the ring should be. Using a set of feeler gauges, see what your gap is currently at. I set mine at .016". Use a file to carefully remove material at the ring gap if an adjustment needs to be made. If your gap is set too tight, you could stick or break a ring due to not having room for expansion. If it is set too loose you will have too much blowby and thus lower compression and performance. Ring gap is important and needs to be checked every time a new piston/ring set is installed.



Setting Ring square with piston.



Measuring the ring end gap.



I like to enhance the arrow on the top of the piston. Too many horror stories of pistons installed backward!
Get out your 2 stroke oil again. Lube up the piston pin bearings, piston pin, piston, piston rod ends and cylinder walls. Install your CAGED piston pin bearings into the rod end. Then fit the piston over the rod and slide the piston pin through to hold it all together, and install the second criclip. TIP: As soon as your piston kit arrives take the piston pin and put it in the fridge, this will cause it to shrink and the installation will be a snap. Once again, ensure the piston is installed facing the correct direction, the arrow points to the exhaust. Also please be sure that the circlips are fully seated, they should be very difficult to turn. OHHH, don't forget that the circlip openings should be either positioned to the top of the piston pin opening or the bottom, never to the side. If you use the Doo clips this will be a non-issue. Put the rings on the piston. They need to be installed with the marked side up. If no mark is present on the ring then the angled side of the ring should be up. (Follow the link at the end of the post to hear my thoughts on why the ring is mounted this way, and my ideas on motor break-in)



Both pistons installed. Notice the heat gun in the background? Even with the piston pins being cold, I still had to heat up one of the pistons to get the pin through easily. Install the base gasket, your new gasket should be the same thickness as the one you removed. Ski Doo codes them by the number of small holes you see at the area of the gasket just to the bottom center in this pic. I thought I used a 6 hole gasket! Hmmm.... If you want to use the recommended sealant on the base gasket, go right ahead. I install them dry....kinda. I give them a VERY LIGHT coat of WD-40. It is a tip I got from an old engine builder a long time ago. Never have had a leak using his method.

[sleddude5]

As you squeeze the ring together and slide the cylinder down over the piston take a moment to ensure your ring ends match up with the ring locater pin installed into the piston. This you can see through the intake tract of the cylinder.



With the cylinders set into place, rotate the crankshaft and make sure the pistons freely move up and down in their bore. It should be a nice smooth rotation. Be sure to listen and feel for any abnormalities.



This next pic is not exactly correct, the y-pipe is already off. After torquing down the cylinders I realized I didn't take a pic...so this is what you get.

Here is how I do it: Mount the y-pipe to the cylinders, snug up the bolts for the y-pipe. This helps with cylinder alignment. I don't have the alignment bar or pin sets, so I do it this way and have had good luck. With the y-pipe mounted to the cylinders, install the cylinder bolts and put them in finger tight. Rotate the crankshaft over to cycle the pistons up and down a few rotations, stop with the pistons in the middle of the cylinder bore. Next torque the cylinders down in a cross pattern. Use two steps to get to the final torque setting, such as if they get torqued to 30 ft-lb, go to 15 on the first step. Now, before the final torque step I loosen the bolts on the y-pipe a bit, then torque to the final value. Then you can remove the y-pipe, because you will have a very, very difficult time getting the motor into the chassis with it on!



Next put the cylinder head on. Make sure the o-rings sit down real nice-like in their grooves on the cylinder top, or you'll get a coolant leak. I put a thin coat of black silicon on the bottom of the cylinder bolt heads, where the bolts heads contact the head (What?). This helps me in two areas, the bolts are less susceptible to loosening, and the silicon provides a little lube when torquing the bolts. Now, torque the head bolts down using the proper torque pattern, once again using two seperate steps to reach the final torque value.



One thing I forgot to mention. You can choose not to, but I always put a thin coat of either oil, or WD-40 on the threads of all the bolts, especially those points where the bolts are steel and the bolt holes are aluminum.

Install and torque the bolts which hold the seal retainer on the PTO end. These bolts get red loctite. In this pic you can see the water pump housing cover is installed.



Put on your exhaust valves.... I mean install the Rotax Automatic Variable Exhaust valves... (Which were introduced to consumers, by the way, on the 1989 Mach 1, eh!)



Here's a pic of the stator and trigger coils installed on the Mag side. This is not tricky, the computer handles the timing, so just put them on the same way they came off. The coils I am pointing to get set in that black silicon I mentioned earlier, and the wire run behind them gets the silicon treatment as well. All of the stator and trigger bolts get a good dose of loctite. The stator bolts, if not sealed, can actually be a source of an air leak, as the back side of the bolts are open to the crankcase.



Flywheel is next. But before this I usually mount the clutch on the other side, this gives you something to hold while trying to torque the flywheel to its proper spec. Clean the mag end of the crank well, and the inside mating area of the flywheel, then put a little locite on the shaft to help keep things in place. I always use a new woodruff key for the flywheel/crank mount area, and also install a new lock washer before putting the flywheel mount nut on. I use a big strap wrench, or you can use your clutch holding tool, to hold the clutch end of the motor, then install the flywheel over the stator, ensuring it mates properly with the woodruff key, then install the lock washer and flywheel nut. Grip tightly onto your clutch holding apparatus as you torque up the flywheel nut.



Install, loctite and torque the bolts which hold on the recoil cup.



And then install your recoil into place. If you were smart you marked everything before you took it off so you know where everything lines back up during assembly.



Lastly put on the motor mount plate and torque the nuts to spec.



This motor is now ready to put into the chassis. Woo Hoo!!

Sadly I have no pics of the motor installation to the chassis, it was about 2:00 AM, I had a ride planned for the next day at 8:00 AM and had to git r done. But here are a few tips...

First thing to do! Place motor into place in the chassis and bolt it up. Then plug in all the electrical connectors and check for spark. It would suck to have everything together and have to tear it down again because of no spark, eh.

It is pretty much impossible to install the motor with the y-pipe on. So leave it off and install after the motor is in.

The reed blocks have a torque spec, but I have always just run them "snug", as it is very hard to get a torque wrench in there.

For this case mod done by Seadooclinic.com, the oil pump basically needs to be turned up all the way. I am gonna talk to them about this some more, I am running like, 18:1 on my gas oil ratio.

Before the reeds go on, bleed that darned oil pump. Yes it is messy! But, you gotta do it. If you look at the last pic I posted you can see the bleeder screw on the front of the oil pump. Make sure your oil reservoir is full and take that screw out. If you are a sissy, you can stuff some rags in there or something, real men just let it run out the bottom of the sled onto the floor. After you get a solid stream of oil, reinstall the bleeder screw.

Also before installing the reeds, check the boots over very well for delamination and cracks. Bubbles in the rubber is the beginning, it goes south fast after that.

Don't forget to add coolant to the sled before you run it! When you first start your sled let it warm up really well, feel the heat exchangers and make sure they are warm. Lift the front end up higher than the back and run the sled. This helps purge air bubbles out of the coolant system. Top off coolant bottle as needed.

Everyone has their own ideas on break-in. I posted mine in another thread earlier today HERE.

I am sure there is more, be patient with me, I'll re-read over the next couple days and add things as I remember them.

Thanks for reading and Dootalking with me!

Jerry C

[sleddude5]

Oh, hey!! My sled is back on the snow again. After letting the motor sit in pieces on the bench for about 10 months I finally came up with the moola and the time to get it all back together..... I didn't even have any bolts left over!!

BEFORE:



AFTER:



THANKS TO MARK AND GREG AT SEADOOCLINIC.COM AND DREW AT SLED-PARTS.COM FOR THE PROFESSIONAL SERVICE. BOTH PLACES ARE VERY HIGHLY RECOMMENDED!!

Jerry C

[MX-Z Man]

GREAT post - thank you.

[FormulaForever]

Good read, well put together post. Hope everything works out good for ya.

[sleddude5]

Here's an update on my sled rebuild project.

I have about 1100 miles on the sled since the rebuild and it has been running fine.

I was originally at about 15:1 on my gas/oil ratio, with no fouled plugs mind you, and after a few hundred miles and a few gallons of oil being used I gave Mark a call at Seadooclinic.com. I basically asked him what my ratio should be and he stated that 40:1 would be a good number to shoot for, so I have been slowly dialing down my oil pump and keeping track of my oil and gas usage. I am now at about 24:1 with further to go. While dialing down the oil I add some premix oil to my gas tank as a safety factor, only about a half quart or so, just in case I go a little too far with the oil pump setting.

The only thing left which concerns me is again with the oil. The stupid friggin' oil pump lever doesn't return all the way. So I worry, especially when riding with the family at slower speeds, that I am getting a false calculation on my oil usage, like using more oil at low throttle settings than needed and less than needed at higher throttle settings.

I wish I would have had the time to send my oil pump to "Bigwormskidoo05" for his oil pump mod. This is how they should come from the factory. I think, if he is still doing this, I'll get it done before next season. HERE is a thread explaining what he does.

So I am waiting on a day when I can get some high speed riding in to get a good gas/oil ratio calculation and I can continue my oil adjusting as I was earlier. Maybe I can get away for a day next week......Anyone wanna go to Cadillac, Mich on Tuesday 2/26/08???

And questions or comments feel free to PM me or e-mail @ sleddude05@hotmail.com.

Jerry C

[RoosterXP]

Jerry, that is an excellent post tons of great info, one thing to do that you didn't mention(not knocking your post by any means!!) is when installing the Rave valves make sure you know what side is up. friend of a friend put them in his sled upside down... yeah not a good thing. other than that great post!!

[TK HO]

PICTURES we all love pictures good stuff

[ZEBEBAD]

Jerry, that is an excellent post tons of great info, one thing to do that you didn't mention(not knocking your post by any means!!) is when installing the Rave valves make sure you know what side is up. friend of a friend put them in his sled upside down... yeah not a good thing. other than that great post!!

If you look one side of the rave valve will say TOP on it .

[RoosterXP]

this is true, but think my buddys saw it?.. haha ended up scraping it up pretty bad...

[Foo Fighter]

Awesome post!! Detailed descriptions along with pics help us newbies out alot! I'm attempting to rebuild from the bottom up and this info will go along way.

Thanks again

[Rev Kev]

Good Post Jerry, Noticed you also using Small Zip Ties as Oil injection Line Clamps, I also use them, Have heard many horror stories of those little lines popping off, and Causing a Burn down/crank Failure. Only takes a few seconds to doo.

[HCSA Rev Rider]

Curious how many miles has this oiled crank lived for now?

[L C I]

Me Too

Curious how many miles has this oiled crank lived for now?