Vibration between 2500 rpm and 3000 rpm

[St-Gerard]

Been meaning to ask if anyone else has had a Engine vibration between 2500 to 3000 rpm , engine is smooth above and below, throttle doesn't seem to make any difference, compression is even, carbs balanced, and cleaned, slide diaphragms all good, only thing haven't looked at are the ACV's . Looking like you have to split the carbs to get at two of them. Thanks in advance, Gerard

 

[kiltman]

Check your heat shields on the exhaust. That appears to be a sweet spot for rpm that if they are loose or are cracked at the mounting bolts they vibrate.

 

[St-Gerard]

Heat shields are intact, while having lower cover off cleaned the ground wire. Pulled the carbs and double checked the idle screws set them at 2&1/4 turns out. Removed ACV' s that are easy to get at looking good and no way they are sticking, diaphragms soft and intact. One thing I haven't done yet is Valve clearances.

 

[Uncle Phil]

Oil Level 'correct'?

 

[Roger]

Check HT leads - and dismantle the plug caps to check for corrosion. (The insides unscrew.)

 

[St-Gerard]

Oil level correct, will check high tension leads and Caps.

 

[Sunday Rider]

Would the condition of the air filter have any impact on this?

Do you get the same result if bike is up on the center stand with rear wheel fee spinning at that RPM in the different gears?

 

[St-Gerard]

K&N filter, maybe, will try in gear as you ask. Vibration in every gear at said RPM speed

 

[St-Gerard]

Cleaned spark caps , removed Resisters and replaced with 3/16th screws, and tighten caps to the wires , still a bit of Vibration between 2500 to 3000 but a lot less and really smooth above 3 grand, happy enough with it, going to ride it.