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Suzuki LT80 bogged down with throttle open

Gary Kozdra

By Gary Kozdra
in Suzuki ATV Forum

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Gary Kozdra Newbie

Gary Kozdra

Posted
Posted

I rebuilt the top end, rebuilt the carb, and replaced the reed. Starts, runs and idles but has no power.  Cant barely move itself with no one on it. Air filter ok. Sounds like its bogged down with throttle open. Compression test showed 140 psi. Plug looks good. Gaskets look good. Im lost. Any suggestions??????

Gary Kozdra Newbie

Gary Kozdra

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Update.

I removed exhaust which may or may not have made  a difference. 

I opened primary case to inspect clutches.

Front clutch looked ok but there was alot of grease in it. Cleaned a bit and reset rollers. Rear clutch seemed not to engage well. Spring wasnt extending fully it seemed I opened it and took the sheen off the contact points and reassembled. Belt looked ok. Ran with primary open and it seemed better but still not enough power to move the bike with weight on it. Still lost. 

  • 3 weeks later...
Hank Montgerard Rookie

Hank Montgerard

Posted
Posted

I have a similar issue with a 1999 lt80; It runs fine until the engine is really hot; then we loose power and eventually it won't stay running. My gear-head friend says he thinks it's an air-leak once it expands. We're going after it tonight with a can of carb-cleaner to try and find/confirm it. We had replaced the carb and put a cheap knock-off topend kit on it (some yahoo had run it without an air-filter and killed the head).

ALso had a sticking clutch problem as the rollers were flattened by the previous owner (maybe a fat/heavy person killed it). That was an ebay purchase.

If you have any success, please share.

-Tks

Hank Montgerard Rookie

Hank Montgerard

Posted
Posted

Forgot to add that we pulled the air and fuel filters/replaced to make sure they weren't starving the engine. Also, killed the auto-oiler and just started mixing oil/fuel to better control the mix. All the gaskets are new with the exception of the carb-gasket (little plastic one) which might end up being where the issue is located.

 

Gary Kozdra Newbie

Gary Kozdra

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I reassembled the clutches and primsry case. Rollers looked good. Just the slightest flat spot on a few of them. Belt was good. When i ran it open the front clutch never seemed to expand but i think its bc the motor didnt spin fast enough to engage it. With everything except the plastics back on it starts and idles fine but with full throttle barely moves the wheels on jack stands.  All gaskets are new. Compression is great. Only thing odd i noticed is motor doesnt sound completely normal and the air temp out of the top end case seems hotter than usual. Im thinking about rebuiling the top end again even though its new. Thought ring clearance was good but maybe its too tight?? Might try a new plug too. What's the best plug to use here??

  • 11 months later...
  • 3 years later...
Hagbard Collaborator

Hagbard

Posted
Posted

OK so, just on the off chance anyone FROM THE FUTURE comes here, I had this EXACT same problem and tried all the same solutions presented here. You wanna know what it was? The starter gear disc that sits behind the primary clutch was filpped the wrong way. The 'post' is supposed to be facing OUT away from the engine, and on both mine, and the parts machine I had, it was the wrong way. Thing is, even installed backwards IT WILL STILL START AND RUN.

BUT WILL NOT MOVE OR REV UP. 

My suspicion is this:  People read about the clutch tweaks, take it all apart, pull a few rollers, lighten the clutch arms by 18g, put it back together and either flip the starter gear or put the washer on the wrong side of the bushing, thereby limiting or eliminating primary clutch travel.  They search online for "LT80 WILL NOT MOVE OR REV UP" in vain, clean the absolute piss out of their carb multiple times til it's got a mirror finish from being boiled alive in lemon juice and purple power. Buy new jets. Buy a new carb.  They check stator alignment and timing. Replace all the electrical components. Twice. Then give up in frustration and sell it to the next guy who goes through the same Sisyphean cycle, only to have the thing roll back down the hill dragging him and his wallet along with it. 

After all my google fu and internet sleuthing here and abroad in the wilds of the ATV forums, I had come to the conclusion that it was flat spots on my rollers and them being gunked up with old grease and mouse feces. All of these things proved to be true, and I ordered all the relevant parts last night. And then had the epiphany whilst browsing the parts fiche at Babbitt's. 

"IT'S FU*%ING BACKWARDS!?!"  

It was, indeed, fu*%ing backwards. So I flipped it. The right way. And after the fifteen thousandth time of taking half the quad apart and putting it all back together again... it fired up and went brap and lit up the tires.

And that's how I got caught ripping around the streets half naked in the rain on a child's ATV screaming "FFFFFFFFFFFFFFFFFFFFFFFUUUUUUUUUUUUUUUUUUUUU************************%%%%%%%%%%%%%%%%%  YEEEEEEEEEEEEEEEEEEEEEAAAAAAAAAAHHHHHH! IT RUUUUNNNNNSS!" and doing donuts in the road at 2am like some sort of deranged two stroke Dr. Frankenstein.

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