i need the our master help regarding my engine prob after mo mods

[=X-II-AIRFORCE-ONE-II-X=]

i installed faito cams, keihin carb 28mm, vixion v spring, brt clutch spring, brt dualband cdi, protec ignition coil and ngk iridium sp. my question is, is it normal to hear scratching sound or somhting bumping i cant explain exactly the sound but its an annoying sound right after you reach each top speed in every gear. i cant rev it anymore because of that sound. is it normal? whats the probable cause of that annoying sound? any help will be delighting ty... help help mga masters

 

[traxxas-modifier]

if you can video it bro, thats better. its hard to determine the sound...

 

[=X-II-AIRFORCE-ONE-II-X=]

the mechanic told me that its from the carb since its a big carb already, so alot of air is going into well that is according to my mechanic i dont know if its true, is it possible on big carb? and he said if i bore up into 57mm or 60mm the sound will be gone. is it true?

 

[lpsnipie_67]

the mechanic told me that its from the carb since its a big carb already, so alot of air is going into well that is according to my mechanic i dont know if its true, is it possible on big carb? and he said if i bore up into 57mm or 60mm the sound will be gone. is it true?

what cam you used? S4-EVO! and what valve clearance?

 

[=X-II-AIRFORCE-ONE-II-X=]

s4 evo, its not from the cam i re open the head theres no sign of cam hitting the piston
the sound happen when you over rev each gear

 

[asrun kamal]

i think it was may be 'valve float'......coz u say that the sound can only be heard when u reach a the top RPM in every gear....
so try to change u,r valve spring....a stiffer valve spring
may this help u .......k

 

[=X-II-AIRFORCE-ONE-II-X=]

tnx ill do dat