I would also check your carb pilot and main jet if it sat for some time . The pilot can plug up really easy. Also the intake boot can leak causing problems. The intake boot is about 10 bucks, we had a hesitation on our red buggy we bought used that also had bent valves. After fixing the valves it still hesitated,found the intake leaking causing a bad part throttle stumble.
The best performance for the least money is 10/11 gram rollers or sliders and a 1500 rpm torque spring.
This was my first upgrade that helped the stock 150cc engine stay in the power band and climb hills.
I just built a 62mm 3mm stroke motor (183cc) and it was fun but a 150cc with a good cylinder head and cam combo will work good if you dont want to dump alot of money in it.
I ported the head on our stock 150 engine 2 years ago and it made a huge gain, just dont go crazy on it. I cleaned up the intake and exhaust a little at a time with a dremel.
The big gain was probally the intake spacer was not matched to the head.
And I did not open the exhaust because it was already matched to the pipe gasket.
I ported heads before for my 68 chevelle and gained some top end. But without a flow bench it is guess work and comon sense.
Good luck and any questions I will try to help you with what has worked in my buggy trial and error experience over the years.
Last edited by Johnny 5; 12-06-2012 at 10:22 PM.
Reason: miss worded
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