Engine Trouble Revs

Red, it sounds like maybe a crankshaft seal leak. The seal on the left side is very thin and has to be in perfect shape to seal right. It can be pryed out with a small thin screwdriver after you take off the stator coil and magneto.

Thanks Jaguar. Is there any way to confirm that before I go rippin out the seal? And couldn't the same be true of the seal on the other side? (small gear, clutch side.) The last time I had a bad seal it was clutch side and it left mix blow by all over the clutch, so would it also do the same thing on the mag side?
I'll pull the mag cover today and check, couldn't hurt. I'm also gonna spritz some water on the intake and change that stupid Chinese spark plug. I didn't install this engine myself so I don't know fer sure what got checked, what didn't. The install itself looks OK, at least the guy didn't drill the frame, but thats all I know about it right now. My way is to K.I.S.S., I'm not gonna rip an engine apart just to find out it was a bad plug wire, so checking for seal blow by is not a bad idea. I just don't know if it would suck enough air to make a difference like that. I guess it could, NEVER say never.
Thanks again for gettin back to me on that. I still think Ice,s problem is the same problem, or close to it anyway. this engine will also rev up with no load, then dog out mid range with a load and has a REAL hard time hitting that WOT sweet spot. Anyway, gonna try to get to it today so I'll know more later.
Big Red.

HeadSmess said:

hahaha!


or in this case the hongkong tortoise?
look at it go!

Click to expand...

As would be true for most of the HT's I've seen. Ya gotta do a "Jaguar" on most of these engines to even pass that tortoise.

http://www.dragonfly75.com/motorbike/index.html

With a reed valve intake a blown seal just releases crank pressure and doesnt suck in air. So just spraying soapy water on the seal edge will reveal bubbles when intake charge is getting past the seal. But on a piston port intake it sucks and blows and I dont know if the soapy water test would show anything (because I have a reed valve intake). Try it and tell me what happens. Last time I pulled that seal I did so without even damaging it. There was nothing wrong with it other than the rubber having been worn down so that there would be less sealing grip on the shaft.

My first bad seal was also on the right side but it was damaged. The left seal is thin and can wear out fast.

jaguar said:

With a reed valve intake a blown seal just releases crank pressure and doesnt suck in air. So just spraying soapy water on the seal edge will reveal bubbles when intake charge is getting past the seal. But on a piston port intake it sucks and blows and I dont know if the soapy water test would show anything (because I have a reed valve intake). Try it and tell me what happens. Last time I pulled that seal I did so without even damaging it. There was nothing wrong with it other than the rubber having been worn down so that there would be less sealing grip on the shaft.

My first bad seal was also on the right side but it was damaged. The left seal is thin and can wear out fast.

Click to expand...

Thanks again Bro, We'll see how things go. I'll figure it out one way or another.
Big Red.

Did ur bike allways do this or did it just start one day. .I had a similar experience. It can be a number of things. .check for air leaks usually on intake or fule lines. Then pull carbarator off look at float chances are your flooding out you can usually tell this when you pull off the air filter and run it try to get the RPM's end of the load if it spits fuel out of the air filter area danach flooding out the bowl you have to bend the prongs to not let it fill up so much only takes a little bit usually vibration causes these cheap cards to screw up recommend you get a better carburetor I've been using the standard ones but you gotta keep dealing with him lots of vibration always causes problems in these bikes