high idle

[JangAlang]

hi everybody..I havent posted in a while. Been A lil busy to do much yet even ride..but for the last week i have been and i am looking for some feedback on what i have experienced. 70 cc Flying horse beach cruiser build, stock nt carb, etc. I have some experience as this is my 2nd motor but sometimes i just cant think it all. Anyways, so i have this high idle. I swapped the carb for another one, tightened it down and its still idling high. I am thinking intake leak or i wouldnt have this idle..yet i still am flabbergasted cause everything is sealed up where it should be.. Now i am going back out in a min to look at it and try a diff. petcock cause i swore i heard it hissing air when i moved it this morning... Could a seal thats going bad cause the high idle? Reason i ask that is cause i thought the other day when i went to put grease on that little bevel gear that i could smell some gas mix mingled with the leftover black grease. I looked but i couldnt see anything wrong with it at the time. I have had to change one before but i couldnt go anywhere when that happened in which case i can still run this bike now..just leanish and hot. Any ideas would be like a tropical cruise right now.. Thanks guys...JANGALANG

 

[2door]

If you're sure the carburetor is sealed to the intake manifold and the manifold gasket is good where it attaches to the cylinder then you might have a bad crankshaft seal. There are two. One behind the magneto rotor (magnet). The other behind the small primary gear on the right side. Either will give you a high idle speed condition if the seal is bad.
Given that you suspect the one behind the small gear it would be a good idea to replace both. New seals are available from most engine kit suppliers. They are different. The thin one goes behind the magneto rotor, the thick one behind the primary gear.

Tom

 

[cannonball2]

I also have a FH engine. The cable that was supplied was slightly short. To the point that even with the adjuster on the carb all the way down it still idled at 1/4 throttle. I removed the round adjuster lock nut and that allowed the adjuster barrel to go down far enough to allow the carb to idle.

Pull the air filter and be sure the slide returns totally to the bottom to rest on the idle adjuster screw.

 

[JangAlang]

Thanks for the replies and the help..i did replace just the seal behind the bevel gear and when i took her out i popped the clutch n heard the air pop through the seal behind the mag. i changed that one n now it purrs. thanks guys now im almost ready to start on the chopper. i will post pic soon as i start it.