I am working on an LT80 that I have had to do some extensive work on over the past few weeks due to plain old bad luck with regard to timing. First, the head gasket blew. Rather than just putting on a new head gasket I put a whole new top end on it. Got compression of 120ish and the cart ran fine for a week or so then lost spark. I replaced the stator and got spark back. The quad ran fine for another month or so (very light use) then started running bad. I did a carb rebuild and that didn't help much so I went ahead and sprung for a new carb, granted it's a China one. I disconnected the oil pump at this time as well. That got the quad running very good again BUT only with no load. Under load it barely moves and bogs out. To be specific, it idles fine on the ground but the moment you you hit the gas, even a little bit, it cuts out without really moving at all. I have doubts that it's the clutches because they were performing perfectly before all these troubles began and have maybe a total of 1/2 hour on them since. I wouldn't imagine them going bad just sitting there. Still, I inspected them and they look normal. Even so, I would think if they were bad I would at least get a little bit of forward movement before the bogging.

With regard to the oil pump removal, I removed the plastic piece at the end of the crank then plugged the carb port and the port on the pump (although I would imagine that one doesn't even matter). Am I missing something there?

Exhaust pipe is clean but, to be sure, I ran the thing with it disconnected and still no go.

I am going to double check for air leaks as well. Any other thoughts?

 

Hmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Seems like everything is checked with the exception of the seals. Might as well stick them in.
So about the timing (you mentioned), you did align the timing marks when installing stator, correct?
I'm not big on electrical. Maybe merryman will chime in if that could be it.

 

Ha ha.

I should have added that I did the crank seals when I did the stator / clutch inspection. Both of them. Heck, as I was that close I figured I might as well go ahead and do them.

I have a collection of vintage golf carts most of which are 2 stokes so I know my way around pretty well. As you know, all 2 stokes are pretty similar. There are just enough differences, though, to cause me to ask questions.

I am pretty sure that I have an air leak somewhere or am missing something on the carb set up or something. The timing is interesting. I am thinking that, as quad runs perfect with its butt up in the air wouldn't that mean that timing is ok? Maybe I am wrong.

 

I may have missed it, but there doesn't seem to be a mention of cleaning the exhaust system out. This is always the third thing I look at on a "gutless" two stoke, after cleaning the carb out and checking compression.

 

"Exhaust pipe is clean but, to be sure, I ran the thing with it disconnected and still no go"
But maybe it could still be plugged. They don't run well w/o exhaust. I burn them out.
So you did align the timing marks?

 

My apologies, for some reason I find Lochlin's post difficult to read, too much information to take in at once? Reed valves, or compression gone again? Or is that in there somewhere too?

 

lol