Motorcycle Repair: Suzuki GN125 performance problem, suzuki gn125, feeler gauge

Question
Hi Chris

I’ve a Suzuki GN125 year 2001 model. I could reach the maximum of 100Kmph where my friend’s bike with same configuration can reach 120Kmph. On this reason I got adjusted my bike’s valves. But serviceman didn’t use any feeler-gauge nor did he look for Top Dead Centre. Now the bike reaches only 85Kmph with the normal sound of engine (I mean without hammering sound of tappets). So please let me know what should I do to get my bike’s full performance?
And let me know the clearance values of exhaust and intake valves in Suzuki GN125!
Thank you.
Bandu

Answer
Hi Bandu.

I don't keep specs on any bikes but my own, so you need to get  the repair manual for your bike for the specs and proceedures.

As far as the guy that adjusted your valves, you need to get your money back from him since he didn't properly service your bike.  I don't know of ANY mechanic that would do a valve adjustment without tools and feeler guages.

Also, as far as top speed, remember that even though you and your friend may have the same model bike and get them tuned the same, because of different sizes and weights of riders, there will be some variance in top speed.  A heavier rider will not get the same speed as a lighter rider.

Good luck and ride safe.
FALCON