LT80, I need your help! I am having the same problem as the guy above. But can not figure out what is going on. I have been all over the internet and every forum try to read about this issue and can't get a definable answer to fixing it.
I have a 2001 LT80, I bought used last fall that had been sitting in a barn for 7 years. I installed a brand new carb, new plug, air filter, brand new battery and cleaned the bike up spotless. Fired it up and has ran great since then. 2 weeks ago my son decided he could go Submarine Willie and ran it in a puddle about 16" deep. Stopping the bike. So I cleaned everything out, flushed out the carb, gear box oil, exhaust, pulled the spark plug, even checked to make sure the air filter was dry. Bike fired up, and we rode for another hour or so. This past Sunday we went out trail riding for an hour or so, came up to a field my son rode around for about 20 minutes more. He shut the bike off, 5 minutes later went to restart it and it would barely turn over. So I took it back to my garage, hit the electric start and it will barely turn the piston, I tried using another brand new battery, still the same result. So I pulled the plug, and the piston spins like no other. So I started thinking do I have to much back pressure. I read one of your comments about this before, so I pulled the exhaust of to look for a plugged exhaust. It was a little coked on the side walls of the exhaust but not bad. So I figured, I'd try to start it with out the exhaust on, plug in. Nope, still slow turning piston. Pull the plug, piston spins like crazy. I did inspect the piston from the exhaust port, prison doesn't look that bad, not grooved up or cracked, I'm a diesel mechanic, so I know bad pistons. I feel if I try to compression test it I'm not going to get a fair reading because of the slow turning crank. So do I take a chance rebuild the top end to find out that wasn't the problem? Or am I facing a bigger problem like a bad bearing somewhere, creating this slow turning over effect. I'm at a loss right now. As I said before, I've read post on this before but have yet to get a rock solid answer on where to go from here. Crazy how I can trouble shoot and rebuild Diesel engines all the time, but an 80cc two stroke is stumping me like this. Thanks for your time in advance.

 

If I were you I'd have a looksee at the starter...it's probably on it's way out especially after being submerged...I added the "optional" recoil starter because the placement of the electric starter is pathetic (bottom of motor)...

 

id prolly think starter also. they usually can spin a semi truck over.

 

Ok. As soon as I read dirt devils post I ordered a new starter on Amazon. Should be here tomorrow. I'll let you know what I find out. I am also going to go through all of the electrical connections to ensure I don't have any questionable connections as well. Thank you both for the advice.

 

Hi I have a lt80 had it for a few years with no problems. I got it out recently and it was cranking over really slow so I bought a new battery and starter but still the same. Had the plug out exhaust off carb cleaned, put it in its back end and cranked it to remove excess fluids but still the same. Any ideas please help!!!!!! Does seem better cranking with the plug out but I’m sure it’s not right

 

Run 12v directly to the starter/starter wire and see if anything changes.