Ok I just rebuilt an 87 lt80. New top end and piston, cleaned carb multiple times, and also reeds. Question is, when it starts, you can take off and run wide open and it runs good once it is cleaned out, but let off the gas and then get back on it half throttle it will sometimes bogg so bad that it will eventually die and then you run the battery dead just trying to start it. Or, sometimes when it is sitting idling, and you go to take off it boggs and finally dies. It acts like it is flooding because then usually when you try to start it you have to hold the throttle wide open and then when it starts you have to keep it wide open untill eventually it cleans out and revs up. I have cleaned both jets completly and also have the needle at the 2nd clip from the top. Moving the needle doesn't seem to help and neither does the idle screw. When I got the bike it was froze up from getting water in the motor and carb. the only thing that I havn't done is put on the hose (boot) from the fan to the airbox, since it was missing. Could that cause a rich bogging condition? I am certain that the carb is clean and jet passages are clear. Is the standard main jet too rich? If so, what jet size should I go to? Any other ideas? Compression is good, and I also switched the petcock to my banshees petcock. Reeds are good and sealing. Please help.

 

This could be electrical but I'd see if the pipe is plugged.
Take the pipe off and blow thru it.
FYI: the air ducting being off isn't the problem.

 

Ok I checked the pipe and it isn't plugged. It definately seems like it is flooding, cause I smell fuel, and when trying to start it, it fires up and bogs, but you have to hold it at wide open for it to clean out.

 

Crank seals and/or intake leaks.
It must be sucking air.

 

Well, I may have to pressure up the motor , but for now I sprayed carb cleaner and couldn't find any leaks. Correct me if I am wrong, but if I have air leaks it should lean out, and run good, but maybe pop sometimes, at least thats what my blaster did and it was very hard to start. When I get the bike reved up and cleaned out, it runs great and idles good. It is just after you let it idle for a couple minutes then try to take off that it boggs. Then you hold it WOT till it cleans out then you can ride it around and it runs great. I cleaned the carb again, and also cleaned the pipe out just to double check. What size main jet should it have stock. I am wondering if someone before me tried to clean the carb and stuck something too big in the jet. I can't read the number any more.

 

I just thought of something. My float must have stuck, because my motor got filled with gas and wouldnt turn over. Since I put on a banshee petcock, could I be getting to much fuel? like if the needle and seat keep letting fuel in and flooding the motor when it's idling?

 

OK, [img]i/expressions/face-icon-small-smile.gif[/img]
A float problem.
Take the carb off, remove the float bowl. I blow thru the fuel supply line and work the float by hand. If working properly, it'll shut off the air flow.
If you haven't removed the float needle seat and cleaned, I'd do that.
A bad needle or seat is VERY rare, but has happened.

 

Ok I think we may have solved the problem. I checked compression and had 120psi. Checked the pipe and it isn't plugged. Checked the reeds and they are sealing. Pressured up the motor and it will hold 8psi just like my blaster. Also have plenty of spark. While it was running, I took off the over flow hose on the carb, and drove it. No fuel came out. When I stopped and let it idle, I had lots of fuel dumpping out of the overflow. Lt80 I believe you are right. THanks. I believe my needle and seat are shot. Opened the carb again found wear on the jet needle, and then checked the needle and seat. When closed, there was just a little blow by so I took out the needle and seat and found that there was a wear grove or wear spot on part of the needle. I am going to try to order a carb kit and hope that it solves my problem. Should I replace the float also? Is it ok if I keep using the banshee petcock? I plugged off the vaccum line on the carb and also took off the oil injection and am mixing 32 to 1. I also plugged the oil injection line. Thanks for helping me out.

 

If there is no fluid in the float, it's fine.
The petcock is OK.
Sounds like you have everything under control.
Happy to help. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Did you fix the LT80 ?
I have an LT80 that is filling up the cylinder with fuel.