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Discussion Starter · #1 ·
Here goes......I have a 1992 Yamaha Exciter 570 II LE that suddenly started bogging horribly. The carbs were cleaned an re-jetted for a Bender single pipe that was put on. The sled ran great for a couple weeks. I was out riding the snowmobile last week, slowed to cross a road, gave then sled some gas and BOG....the snowmobile started bogging. Tried a new belt and plugs, still bogged. I got the sled home, checked the compression and I had 120+/120+ in the two cyliders. Good compression. I found a seized carrier idler wheel on the suspension that was worn down into the aluminum of the wheel. I changed the wheel and put new bearings on both wheels on either side. The sled still bogged. Upon further inspection, I noticed the secondary clutch had a ton of play in it. I inspected further and found that the jackshaft bearing had gone out, beyond seizing to nothing left and the jackshaft bearing housing was cracked and ruined. The jackshaft bearing housing and bearing were replaced. The jackshaft was still in good shape so just the bearing and housing were replaced. The sled STILL bogs! The sled starts great, idles perfect and revs up awesome -> with belt off it revs up awesome. The primary clutch seems to operate great, compressing and decompressing with the rpms of the motor. I can get on the sled and drive to like 10-15 MPH starting out with no problems but as soon as I get on the throttle a bit, she bogs down and if I crack the throttle open, the sled really slows down and barely moves. As soon as I let up the throttle, right back to perfect idle and a slow cruise. TORS system is disconnected and hooked into itself just like everyone does it. I think it is a secondary clutch issue. The spring is fine, but is it possible that when the jackshaft bearing went out and seized for a bit, the spring slipped out of one of the holes into a different one or into one of the 3 different settings in the secondary? Which setting is the average normal setting on the inside of the secondary, A....B....or C??? The belt also seems to sit like 1/8 inch into the sheaves on the secondary now, is that to far in when just sitting still? This problem is really frustrating and Winter is disappearing quickly, does anyone have ANY ideas??? Thank you very much for any help!!
 

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Your belt should ride up out of the secondary a tiny bit when you are stopped. It shouldn't be down in the sheaves at all. Did you preload the spring when you reassembled the secondary? Having the spring in the wrong hole shouldn't make that much of a difference.
 

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Discussion Starter · #3 ·
How tight do I have to pre-load the spring? This is tough to do without the clutch holder tool, I'll tell you that! Initially the clutch was never taken apart and it still bogged, thats why I think the spring jumped some how losing the "loading"?!? It looks like the spring jumped because I can see a "scrape" line on the clutch from the spring tip. The belt does sit like 1/8 inch below the top of the sheaves, that is too low...right? Is that possible? I dunno, this sucks!!
 

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Are you sure the spring is alright? I think you're going to have to disassemble the clutch. If you have two people, one to press the helix in and the other to put the snapring on, it's possible to do without a clutch tool. Also, woodworking clamps can be used somewhat easily for clutch work.
 

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Discussion Starter · #5 ·
I have a brand new spring, even though the old one was ok. I think you are right on with the preloading. A buddy and I tried doing this today and we ended up breaking one of the the plastic cog things on the inside of the secondary, you know, the cogs that are labeled "A, B, and C". Now we need to wait and get a new plastic piece. Does it sound like a preloading issue for sure to you? I know that the belt shouldn't be sitting 1/8 inch below the top of the sheaves, but the preloading is probably why huh?
 

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To be honest with you, I'm no expert on clutching. If the spring isn't preloaded, I think you'll notice it most starting off because it isn't backshifting properly. It never shifted back into low gear, thus your belt riding an 1/8th inch down inside the sheaves. That's how my friend's Ski Doo acted. Another thing it could do is just allow the secondary to upshift way too fast when you accelerate. That would be consistent with what is happening to you. I'm just giving you some preliminary help because nobody else was posting. Maybe an expert will lend a hand soon.
 

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it sounds to me like a fuel prob. check filter, pump, in tank filter,all lines. see what that does oh and pull the carb apart and make shure one of the jets didnt come loose. ive had that happen
 

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Discussion Starter · #8 ·
ULTRArmk, did all that today, Went through the carbs....no probs. Tried a new fuel pump. Sled did the same thing with a new fuel pump. The sled idles perfectly. The sled revs up great when the belt is off, it only bogs when I am on the thing riding. One more thing, the sled seems to bog worse in looser snow, it seems to get up and go on roads where the snow is packed hard.
 

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That's still consistent with a clutching issue. With less resistance on the packed snow, the power of the motor can more easily overcome resistance when the clutches upshift. In deeper snow, the motor can't keep up and it will bog, especially if it isn't backshifting correctly.
 
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