Better than snowshoes

I seem to be aging quickly if my latest vehicular purchases are any indication, first a klr650 and now a 2001 ski doo touring e.

Whats so old manish about this snowmobile? Three things, firstly the engine is a fan cooled 377 rotax which has been in production since before I was alive. Secondly the long deep lug track which is perfect for breaking trail. Thirdly it's got electric start and reverse ! Much luxury! 
 

More importantly what's so grm about this sled? It was dirt cheap, pretty much scrap by the pound pricing. Why? Because it had a trashed pto side crank bearing. 
 

Olbigarory trailer pic before we get started.

Step one, remove engine. Fortunately since it's air cooled it required only about an hour to do. Which allowed me time to put two coats of high heat paint on the exhaust. 
 

With the motor out it was time to clear space on my workbench, which is a project in itself. Then I lay down my patented fresh cardboard engine building surface and begin tear down. Everything went smooth except the mag which required a puller and a 3ft breaker bar to get off the crank. 

This all started Wednesday and this is where we sit today, waiting for crank bearings , gasket kit, and crank seals to arrive on Tuesday. Oh and some fresh rings because I'm already in there.

Why not punch it out to a 390 while you're in there? 

In reply to adam525i :

Mostly cost, also I already have a fast sled this is mostly going to be a family and friends loaner machine until my daughter is old enough to ride.

Outer bearing came off nicely with a little heat and a nice witness mark to show where the new one will go. Going to leave the inner until the new bearings arrive. 

Since I have no idea how a snowmobile works, what of all of this work is necessary to replace the bad pto bearing?  
 

I'm wondering how long it would have taken you to just replace the bad part and get it back together. 

In reply to jfryjfry :

Basically snowmobiles use a belt driven cvt set up to get power from the motor to a gear case that then turns a cogged driveshaft which in turn drives the track. 
I guess I got a bit bogged down in the jargon earlier.
In the simplest terms the motor has 2 bad crank bearings. Because it's a two stroke they are ball bearings so they are cheap so I took the gamble that they didn't do any major internal damage to the motor when they went and bought the sled. Knowing that even if the motor was trash it was worth fixing for me. 

The crank bearings are only 50$ each but if you had to pay the 1500$ labour bill at a shop then the sled might not be worth saving. Fortunately like many here my labour is worthless. 

I've been wanting to try pressing a crank apart for a while on a two stoke. So this is a baby step towards that. 377 motors are common enough that if I mess it up I can find another one easily. 

While I am familiar enough with sled basics, I am very curious about a few details. So I will watch and occasionally question. The first of which is the con rods. Is the color a result of their alloy, heat treatment, or just a surface coating and what process was used?

In reply to TurnerX19 :

Great question about the rods. Honestly, I have no idea why they are that colour. They are both the same colour though so I assume it's the way they left the factory. 
I can tell you I was very happy the rods had no vertical play and that the two center crank bearings seem smooth and quiet. 

Here's a better picture of the crank from when I removed the bottom half of the engine case. 

The witness marks on the counter weight next to the inner bearing are scary, maybe just pieces of the disintegrating bearing...

TurnerX19 said:

While I am familiar enough with sled basics, I am very curious about a few details. So I will watch and occasionally question. The first of which is the con rods. Is the color a result of their alloy, heat treatment, or just a surface coating and what process was used?

All the rotax engines I've had apart (377, 440, and 600 triple) have all had similar color on the rods. Even when I've purchased rebuilt cranks, the rods have been that color so I always just assumed it was manufacturing process or a side effect of a fuel/oil varnish on them. 

TurnerX19 said:

The witness marks on the counter weight next to the inner bearing are scary, maybe just pieces of the disintegrating bearing...

Yeah, bearing material that got caught in the action. Luckily none of the balls made it out of the bearings which could have cracked the cases.

I'm going to luckily clean up that counterweight and put it back together. It's a low compression, low performance motor. I think it will be fine. 

Waiting on parts so tonight I cleaned the cases and case mounting surfaces. 

Then I went ahead and honed the cylinders. Don't mind the goop I coated them in to prevent flash rust. I'll rinse them in brake clean then wipe them down with injection oil before final assembly. 

Finished off by giving the sled itself a good clean. Everything turned out nice on the sled except the windshield. I'll have to source a replacement. They are available new for around 120$ but I'll try and find a good used first. 

Looks like a fun project, I've always wanted a sled, just never wanted to live where its cold enough to warrant having one.  My dad grew up outside buffalo and his old ski-doo 440 from the 70s sat in my grandparents garage blow up my entire child hood, womp womp, lol

In reply to fouckhest :

They are a great deal of fun, I wish we had more snow where I live . It's a 3 month season here at best. I can extend that by a month by leaving my sled at my fathers an hour north of here during a good year.

Tonight I had to walk away from the project. Head wasn't in the game. Got the old inner bearing removed but even with the crank at 0c and the bearing at almost 200c the bearing wouldn't slip over the crank. Thinking I'll either build a puller or need a bigger temperature differential.

Yesterday I asked for help, and received it. A neighbour with a lathe helped me clean up the bearing surface on the crank with some quick file work and emery cloth. 

With that done we made a little puller to use the stock crank bolt to pull the bearing on. Then proceeded to push the inner bearing too far on. A trip to another neighbour netted us a bearing puller that we used to remedy our first mistake. Just like that the crank was ready to rock. 
 

You and your neighbors are awesome

jfryjfry said:

You and your neighbors are awesome

Thank you. Having knowledge people around is always a big help. 

Getting mentally ready for tonight. Hoping to get the top end assembled. Then I can get accessories on and it back in the sled sooner than later. 
 

This is as it sits now. As per the manual I used the stator to align the case halves.

Some parts guy sold me the wrong fan belt (I'm the parts guy but in my defence the listing is wrong). Regardless, it now looks like an engine again. With the proper fan belt I hope to get tomorrow morning I'll have the motor ready to drop in in less than half an hour. Will it make noise this weekend ? Stay tuned. 

Well, it all looks right. But there's no spark. Going to take the ignition apart after lunch I guess.

Well this is humbling, when I pulled the flywheel I must have used too long of a bolt. Stator damage is obviously new, and expensive. 
 

Are there any sled dismantlers out your way that you could get a used one from? For us it was Jo Jo's in Bright, On and I spent way too much there keeping my old Indy Trail going lol.

adam525i said:

Are there any sled dismantlers out your way that you could get a used one from? For us it was Jo Jo's in Bright, On and I spent way too much there keeping my old Indy Trail going lol.

There's a few, but because this sled has electronic reverse (that's right the 2 stroke motor just starts running in reverse rotation) it's not a really common stator. I've found a new one for 150CAD$ but I'll hold off a few days in case I can find a used one. 

New stator showed up in the mail today! Wired it in quickly to make sure it had spark and it does! Will do more work after I go give a buddy a hand tonight. Updates to come. 
One plug did need to be changed but the  wire colours were the correct wire so I just reused the oe plugs.