1990 Yamaha Exciter Restore

I got the cases split and since the primary clutch appears to have taken some damage at some point in time we are going to ensure the crank shaft is true.

 

Now on to the nightmare and I never thought it was going to be this bad. I have 3 pile of shit rear skids and not one of them has a usable wheel bearing and every nut and bolt is rusted to death. And all the shocks I have are complete junk.







 
A friend of mine did however have a brand new track he gave me which is in great shape and I picked up a pile of Exciter parts for 50 bucks that will help me with reassmebly. I bought all new bearings for the wheels on the rear skid which was not cheep at all.

My big question right now is WHY IN HELL did yamaha think it was good idea to use aluminum shafts on the rear suspension. All 3 of the of the front pivot arms (Larger arm on the skid) have the aluminum shaft seized inside of the pivot arm. I'm at a loss on how to repair or fix this right now so threw my wrenches, WB40, torch and impact down on the ground and went inside to sit on the couch late last night. LOL. Back at tonight.

 
Oh and I forgot to tell you guys. This pissed me off a little because sled I'm working on I paid 500 bucks for. It started, ran and rode when I bought it so I figured it was worth it until I started tearing it apart. While rebuilding this pile of shit another Exciter came about for 300 bucks in way better shape. LOL. So I bought it. Backup sled.









 
Aluminum shafts have to be milled out if you have tried everything else. When they corrode they expand beyond belief and are impossible to remove any other way than in a mill or super heavy duty drill press. The smaller shafts in the rear arms arent as bad to mill out. The aluminum shafts just, plain suck.
Hey Nick, dont feel bad about your purchases. Just be glad your not one of the poor ba#$ards that bought or will buy one of the $600-1200 Exciters that look a hell of a lot rougher than your project. 90% of the exciters on craigs list are junk, or junk by means of being way over priced. Most of what I see are in actuallality $150-300 sleds. Unless you have a super show room condition (or damn near) Exciter SX, there is no way they are worth over $1,000. Im sure you understand this as now you know what it actually takes to make these things decent, reliable machines again after you factor in the cost of purchess and parts.
I have bought many exciters over the last 10 years or so and 99% of them had bad mag side crank seals. Some didnt run, some ran on one cylinder due to a melted mag piston due to a bad mag seal. I have never seen a lean condtion on the pto. The mag side is always the bad one.
Good luck with your project. Holler if ya need anything.
 
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P.S....ATF and acetone is the best penetrating lube I have ever used next to Kroil....... And if your p*ssed now........wait untill you get to the scissor arms in the front end. ;):D
 
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Throttle Junkie. We definitely need to get together for a ride once the snow is here.
 
Ok found this thread and am considering a exciter for my kids first sled. found one for 700 that im told has a rebuilt motor in it...I want to upgrade the track...what are my options??? i know its a 121 15 but i am wondering if a 1.25 paddle will clear??? any help appreciated and thanks for letting me hijack your thread....I plan on tearing sled down as a summer project to teach my kid how to work on these things....but we will ride it this winter first...

thx in advance
 
$700 is too much if it needs a track, seat cover, or anything else. Why was the motor rebuilt? Were the crank seals replaced too?? A lot of guys claim they "rebuilt" the motor and only do a top end. Chances are they melted the mag piston due to a leaky seal. If only the top end was rebuilt, it will burn down again if this was the case.
A 1.25" track will work, however that does not leave much room to evacuate the snow out of the tunnel. A 1" track is plenty on these machines, because they only have about 77hp.
 
Ensured crankshaft wasn't bent over the weekend because the primary had damage on it. Crankshaft is pretty much true with .002 runout on the dial indicator. Less than a **** hair.

 
How was the run out on the mag side?? I had some that were perfect on the pto but the mag side made the dial indicator look like a windshield wiper.
 
Checked both sides. All good. Both sides had a run out below .003

I end up finding shocks. I found the short and the long one for the skid assembly. Recieved the short one on Friday. It's a brand new yamaha shock / part number but the piston on the shock has to be manually pulled out and pushed back in. The 1990 is NOT a coil over shock / spring assmbly. Is the stock Yamaha shock an oil shock / not a gas shock? Because I have a clapped out kimpex that rebounds slowly on its own. The 2 old yamaha shocks I have a blown completely out. Should the shock piston have to pushed in and pulled out manually?
 
Who told you the 90 was a coil over shock?? 91-93 exciter is a coil over skid. Stock yamaha shocks for your skid are hydraulic and need to be pulled back once compressed. The kimpex are gas charged and will rebound on their own.
 
Nobody told me it was a coil over shock I was just being descriptive in my post. I had just never seen a shock that did not reboud on its own because I'm young and dumb :). Now I undertand that the shock is basically just a oil filled damper and the spring performs the rebound. I will make sure to wear my kidney belt and back brace when I'm riding this thing if I eve get it going.

I boinged an SPI circlip across the garage last night. Looked for it for an hour and gave up. Anyone have a spare one laying around they want to send me?
 
Hey nick, if there is a cycle shop in your area that carries Wiseco pistons, they should have the circlips you need. part number CW20, heck your local yami dealer may have them in stock as well.
 
It is unbelievable to me to condition of the skid assembly and the time I have getting this thing apart to make it all right. Heated up one of the linkage assemblies last night with the torch to bang out the aluminum shaft. Aluminum on Steel Yamaha? Really?! WTF. This stupid aluminum shaft cost 80 bucks. Hopefully I can get one made out of steel. I also plan on putting grease fittings on the linkage so they can be lubed regularly so this never happens again.



 
Heck, that aint noth'n. Most of the time heat doesnt do any good and milling them out is the only option. The aluminum shafts are fine IF they are lubed every season or at least every other. Most of the skids I have torn apart probably never saw grease besides what the factory put in.
I bet I have over 8hrs in the last skid that I refurbished. They are very, very time consuming. BTW, carefull with the heat, you could make those arms brittle.
 
Just an update where we stand. Motor is completely rebuilt. New crank seals and new top end. I'm getting a couple shafts made for the linkage for the skid. Once those are done I can put the skid back together. I have brand new shock obsorbers for the skid a well. We are going to do a leak down test on the motor before we put it back in the sled just to make sure the new seals are holding.

I read in another thread that the 2 outer wheels on the front drive shaft are not needed? Is this true? If so this makes my life a lot easier because those wheels are discontinued. I melted one when I hit the drive shaft with the torch.

How about repair for the bottom in the picture below? Should I pop rivet a sheet of aluminum across the bottom?





 
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I'd def do some kind of patch work there. pop rivet a thin sheet of aluminum to her. i just went thru the same deal with the aluminum shaft. drilled mine out with a 3/4 bit with a hand drill and made a new steel shaft with a piece of 3/4 solid round. 3/4 is too loose so i have a few thin shims tacked on to take up the slop. i was lucky and was able to get my top aluminum shaft out and able to reuse. good luck with all you got going on there grasshopper!
 
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