Topping out at 20 mph...Too much fuel ?

[ibcnya]

If it still runs better when closing the valve and your float is properly adjusted then in my opinion you need a smaller jet. You can first try to lower the needle to its lowest setting by raising the clip to the top notch on the needle. Most say this only effects low to mid but at least on mine when the needle is all the way down it never comes completely out of the jet tube so it will lean it out a bit on top end.

Already running a dellorto #65 main. Im gonna try the float adjustment tomorrow and ill let you know.

 

[tesjpurple]

Bought a used bike with a 48CC engine and I have been having the same problem as the original poster. The old plug was as black as coal and I have also noticed unburned fuel at the muffler and the muffler appears to be modified (thinking about ordering a new one). Running a mixture of 32 to 1.

I have ordered a new plug, I'm sure there are no air leaks, I've adjusted the float, and noticed that the cover on the ignition coil is split with the wire exposed (waiting for a new coil) and a new motor mount for the back of the motor (currently missing/also on order). Unable to test the changes until the new parts arrive.

Can anyone advise what I should set the plug gap at? Anything else I should look at regarding the problem?