I have a custom buildt bike with an 88 evo and a 103 cui engine with rev tec top. s&s g carburator. When i drive downhill or on flat road and try to keep a low rpm on the engine it jumps like it`s running on kangoro petrol. I don`t have this problem when i turn the gas handle to cruising speed.

Does anybody have any suggestions?

Kindly

Mr. Hansen
From Norway

http://img67.imageshack.us/img67/5364/9967478728wk.jpg

 

What gear(s) are you in and what speed(s) are you going when this happens?

 

The gearbox is Sputhe 5 gear. It happens when i drive in low rpm on 3-4 or 5 gear and try to keep a low speed about 20-40 km/h.

 

I think you're running too low an engine rpm for the speed you're going. Drop a gear at that low a speed, and see if that cures it. Hard on the main bearings, too.

 

Id have to agree with poco, sounds like your lugging the tranny! Does it have a tach? Optimal RPM for any gear is between 2800-3300 RPM. 40 km/hr is only 25 mph, you shouldnt be out of 2nd gear at that speed! Dont lug your tranny dude, bad bad things will happen!