This is my first post on the site, and im hoping somebody can help me out.... i posted in the yamaha forum, but i think this thread is better suited here...

I just bought a new keihin pwk28 for my 2000 blaster. the blaster drivetrain upgrade are as follows:

-cylinder port and polish
-high compression head(gasket kit)
-61mm (1mm over) weisco piston
-raised cylinder base(exaust port timing)
-boysen power reeds
-0.5" reed spacer
-fmf expansion chamber and muffler
-k&n air filter w/outerwear
-stock airbox lid removed
-oil injectors blocked off

i usually ride at altitudes between sea level and 5,000 ft...
anybody have any suggestions on the jetting of the new carb??? thanks.

 

Start with what you have, run the machine down the road or pit for about a half mile wide open, don't let off gas, shut off machine, coast to a stop. Pull the spark plugs and see what color they are. Jetting is a fine art to some. Color of the plug and burn quality are what counts. You wahta nice tan color!

 

thanks for the advice bro, i will give that a shot first. then possible try adjusting the mixture screws on the carb from there...

 

The Idle air mixture screw won't do much if anything for the machine except for the idle of course. So your best bet is to adjust the jet needle for mid range, and main jet for wide open. Although too large or to small of main will interupt the midrange. If the machine has a BAAAAHHHHAAH like all air sound to it, it is probabley too lean and you need a bigger jet. If it spits and sputters it usually is too rich. Popping sound is also a sign of being too lean. If the plug is really wet u know it is rich. You do not want the spark plug to be white or metallic grey. Grey is usually sign of being lean and piston or engine damage occuring. Tannish brown is what u want to achieve. Like I said the mixture screw will not affect mid or wide open. if it runs rich at idle, it may have too large of pilot jet-idle jet or float level set too high, or mixture screw way out of adjustment.

MAKE SURE YOU RUN GOOD OIL AT 32:1 sounds like you have a screamer!!! 4oz oil per gal of gas, unless oil injected and I think the blaster is, can't remember? Either way run some Belray MC1 or Amsoil something of good Quality not Casey's General store brand if ya know what I mean!

Good luck let me know if you get it going!