I've had my motor not idle until I found that the carb was not fitted all the way in, or at least not enough so that it covers the slits that are on the carb..... causing the motor to draw air through the slits. Make sure your carb is fitted on the intake so that the slits are closed off and not drawing any air.
Bike starts up fine, bogs out after 100 ft , major pain to start up again
- Thread starter Mr buenomoreno
- Start date
What you may need to do I rejet. .66mm should do the trick. Test all needle settings until you find the one that has it idle. Seal the connection between the manifold and carb with electrical tape. Check all your gaskets. Try a new mag and cdi. Make sure your plug isn't fouled. If none of these work, I can't help ya.
If it ran fine on your other bike, it shouldn't be the jets. Did you check for air leaks? Get some carb cleaner and start spraying around the carb.
Hey everyone it's been a while since I posted this thread but what I found is the inside of the cylinder wall there was scraping on the intake and exhaust sides of it so I ordered a replacement cylinder and piston head, along with new gaskets and set it to the leanest setting. Started it up today no problem, it idles and pulls just fine, however sometimes when idling the engine revs high and I have to play with the idle screw to get the rpm to go down. Also since the cylinder head is new does this mean I have to go through the breaking in process again?
not sure of your terminology, as cylinder and head and piston are all separate parts - it will need to get the rings seated again - also, I like to oil the cylinder base gasket when I put a cylinder on just to be sure it doesn't develop a bit of air leak which might cause an idling problem
Sorry it auto corrected , the cylinder and piston are new. Also Is an air leak in the base of the cylinder (or anywhere else for that matter) what is possibly causing the idle speed to increase on its own
yes, rising idle rate usually means an air leak and that leak can be from the base gasket - just lift it up an inch or so and smear oil on it, then re-torque it down
Sounds good I'm at work now but I will do that when I get home and post the results thanks for the help everyone
Ok so the bike won't run idle or accelerate unless the carb is at mid choke which means there's an air leak somewhere or I'm too lean, but I can't find the leak, where should I look and how can I tell if I've found it
So I got a new spark plug which gave the bike a somewhat steady idle without needing to use the choke. That wasn't achievable before so now that it can idle I found another air leak but I'm not sure how to fix this one its between the carb and intake. i should mention im running 8 oz oil:1 gal gas on the leanest needle setting you can see in this video
The piston , piston rings and cylinder were just replaced which is why I'm running that oil gas ratio
has to be either that the carb is not sealing onto the intake, or the top cap of carb is cross threaded
one can stick something in carb till it hits the inside stop and measure how far it is in, then make a scratch on intake at that distance to see if carb goes on all the way - while carb is off, look for lumps or cracks on intake
one can stick something in carb till it hits the inside stop and measure how far it is in, then make a scratch on intake at that distance to see if carb goes on all the way - while carb is off, look for lumps or cracks on intake
As crassius mentioned, check for casting imperfections. I had to file and sand off casting ridges on the intake where the carb mounts. You can check through some older threads as I think some guys have used rtv silicone to seal up air leaks at the carb mount.
I used yellow Teflon tape( the one rated for gas) on the carb top cap which helped a bit after further inspection the carb clamp seemed tight but not tight enough so after tightening the clamp the bike rode with no problems at all
Good news. It goes to show you that the problems that come up are usually pretty simple and it's a good idea to go through the real basics when issues come up. Having said that it is easy to overlook things.
