Spark knock!!

[Triplecrown421]

blaster is what seems to be spark knocking at peak RPM. when almost hitting rev limmit theres a consident ticking noise almost like something is tapping bad. and it isent a lose vibrating bolt or somethin like that. if it is spark knock whats in the best way i should go abouts it? anyone had this problem before and solve it.

 

[Surfrjag]

for some reason your lean up top probobly. check for air leaks or just go ahead and jet to a larger main jet. tell us more about the blaster plz

 

[Budget_Blaster]

Whats ur jetting look like?What mods you got done?Any changes recently to your fuel jetting oil type and so on?

 

[Awk08]

pinging at rpm is detonation, and is usually caused by the above mentioned lean jetting, advanced timing or an airleak, which need immediete attention

could also be caused by bad, or low octane fuel
weak spark ??? bad plug boot/wire ???

leakdown test, plug chop, change fuel, 92/93 octane mixed 32:1 and new plug, confirm or retard timing back to stock

 

[quadsrus1]

X2 on that sir good luck keep us posted tell us more specs for more help

 

[Triplecrown421]

bike has a mild engine build bored over alittle mean port job jetted i think its just a 240 jet i think stock was 220? fmf system and throttle spacer other then that completly stock. i wonder i had scrowed around wit base gaskets for a bit before i have like 2 pieces of loosleaf as a base wit sylicone to try and raise the compression for more torc but notice it was too much due to the spark knock all the time. i went back to the origional gasket and seemed to fix it alittle better now its just random at times. its VERY bad when i run regular gas. i dont think its an engine leak cuz i made a compressoin tester for the whole engine and it dident leak and air. i also made the stock timeing plate adjustable but notching it but kept it to stock to find this problem. and its not the spark cuzz shes a new plug and i swapped out the coil and wire with a different one and no diff. maybe my jetting is off i never changed the pilot but that shouldent do er, the bike seems it could run better if i had the proper jet to it maybe\?

 

[Blaaster]

Bump up the main jet a couple, do a plug chop and take it from there.

Needle in the middle clip.

"Edit" Just noticed you said FMF system, if that is pipe and silencer, take the main jet to #270 or bigger, then plug chop.

 

[Awk08]

Bump up the main jet a couple, do a plug chop and take it from there.

Needle in the middle clip.

"Edit" Just noticed you said FMF system, if that is pipe and silencer, take the main jet to #270 or bigger, then plug chop.

i second that motion, a 220/240 main is way too small for almost any aftermarket pipe

 

[Triplecrown421]

alrght boys i gotta 260 at the shop ill throw that in and see what happens

 

[Budget_Blaster]

With my .050 stock jug fmf sst2 and powercore 2 silencer +4 timing vf3's i was at 280-290 i still dont think 260 is enough.

 

[roadkill]

he said it has a port job too. so maybe go for a 300 main

 

[Triplecrown421]

might just buy a 280 to try aswell should pickup a pilot and new needle aswell, noticed the bike's revs raises a bit after 5 to 10 seconds of idle. and i did try my tester on it recently so no leaks.

 

[Blaaster]

No need to mess with the pilot unless it is not stock, 32.5 should work just fine.