Hello Everyone, I am new to this forum and have found quite a bit of useful information so far. I recently acquired a 2003 Suzuki LT80 from a coworker. He stated it stalled one day about a year ago so he parked it and it has sat there ever since. I started working on it to get it running again. The throttle inside the carburetor was completely seized so that is where I started. I was able to rebuild the carburetor and when I went to start it I found the engine will not crank. I turned the engine by hand to make sure it is not seized. The engine spins just fine by hand. After repairing the poor connection for the starter relay I found the starter will spin when I unbolted it and pulled it away from the flywheel. When I reinstalled the starter it will rotate the engine about a half turn then stop, then if I hit the switch again it will go another half turn then stop. I put power directly to the starter and it still does the same thing. If I remove the spark plug the starter will spin the engine just fine. I know there is the option of installing a pull start recoil, but I do not want to invest too much money in this until I know the engine is good and runs. I am thinking the starter is just weak, but I was wondering if anyone has ever had this same issue and resolved it. I found some posts describing this same issue, but I could not find one that showed a resolution. Thank you in advance for helping getting this issue resolved for me.

 

See the post Lt80 2005 seized? almost exactly the same symptoms, (plus several more problems). However get the battery tested, after a year of standing it is probably shot.

 

It's the starter.

 

I did some more digging last night. It appears the starter is not the issue. I pulled the head off and cranked the engine with the starter. The engine spins until the piston gets to about 2" from the top of the cylinder then stops. I spun the engine by hand and the engine is really hard to turn until the piston gets down below that same point again, then it spins rather easily. I then took the cylinder off and found the piston is really tight on the top of the connecting rod, I can barely pivot the piston at all. I removed the pin and took out the piston. The bearing inside there is completely rusted. The piston and cylinder both have some surface oxidation/corrosion on them. I am thinking this engine took in water at some point and now the top end needs to be rebuilt.

Quick question though, does anyone know the thread size and pitch of the crankshaft nut on the left side of the engine? I tried to turn the engine with an impact and ended up stripping the nut completely. The crank threads are damaged as well, but I think they are salvageable. I could only find the part number for the nut which is 09140-12037, but I cannot find info about the threads.

 

I'll see if I can find the clutch side thread size.
Please Get a Suzuki piston (next size up) and get your oem cylinder bored to it.
I only use Suzuki parts.