Hi all.. Everytime whenever i travel my ktm to the speed of 90km/h, my bike at that speed will vibrate harder and have sounds of metal hitting each other. But when i travel at 91km/h onwards, the vibration and the sound dies and the engine sounds normal again. Is it because of the opening of the valve that causes this or the CDI ?

-If it's the valve that is opening at the speed of 90km/h using a size 40 sproket, will my valve opens at 80km/h(for exp:anything lower than 90km/h) if i use a size 42 or 45 sproket ?

my friends sp also like tat....at rpm 5k it vibrate like hell. i also duno wats the problem.

maybe its yr tuning at full throttle is wrong. i juz guess guess. no prove.
but y u think it yr valve?

your valve opens at certain rpm. not by speed limit.

does the vibration only happen within a specific RPM range? maybe your carb isn't well tuned thus having some flat spot creating a surge in the RPM climbs.

It's probably the power valve in it's half open state. do not cruise in this state as u could break ur valve into 2. do a clean rev and cruise on ur higher gears. hope this helps.

it probably the power valve rattling at the exhaust port..