should i jet it or not?

[bubba813]

I have a 1995 yamaha blaster bored 50 over boyseen racing reed's aftermarket clutch fmf muffler with stock header.I was wondering if i should jet it or not if i should let me know what size thanks.

 

[scotj77]

maybe bump up to a 250 if you have the airbox lid on. 270 if you have it off. leave the pilot jet alone

 

[bubba813]

alright but dose it make any differences with air box lid on or off ?

 

[Blaaster]

Airbox lid on less air, lid off more air, so leaner mixture, larger jet needed for cooling.

 

[bubba813]

alright thanks man ill try that.

 

[roadkill]

with the lid off its less restrictive so it can get more air and make more power, but you have to go to a bigger main jet with it off

 

[bubba813]

alright i was thinking about goin with a 270 with air box lid off could i put a 270 & a uni airfilter on it will it be fine?

 

[Blaner]

its hard to tell you what you must use, jetting is not a once off thing, its not an on/off thing like a light switch, its a process, you need to experiment with various jets and settings and do certain tests such as plug chops to find what jets you need. your elevation, atmospheric pressures, temperatures and humdity all play a role in making everybodies jetting needs unique.

read up some of the stickies in the engine section to learn a bit more!

 

[roadkill]

my blaster when it only had a bills pipe and a uni filter was dead on with a 280 main

 

[bubba813]

okay ill just try it with a 270 & see what happen's.