• big valve head

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 #11436  by junk yard dog
 Thu Mar 01, 2018 9:12 am
I have a stock howit 150, will a head with bigger valves and a a9 cam wake this thing up? I already have the hammerhead exhaust, jap 24mm carb , and air filter... 115 variator, 10 gram weights and yellow contra spring. So far its going good flat out i hit about 8500 rpm and can climb any hill. so what do you think travis?
 #11523  by myvt365
 Tue Mar 13, 2018 10:05 am
I do think you will notice a performance gain with the A9 cam the duration of valves being open are going to increase the air in the combustion chamber. your running into what I am dealing with your stock carb is still with the factory jets you have increased the air into the carb and the exhaust is free flowing I wouldn't be surprised if you are running a tad lean on you carb jetting. TBH id start with fine turning the carb and see is that helps.