Jetting Please help!

C

cowentz

Guest
I know this question is asked all the time and it is probably one of the hardest questions to answer. But I need help on where to start with jetting. I recieved a 2003 blaster on a trade and it was not running due to needing carb cleaned. It had a brand new top end that might have only been started a few times. I cleand carb and started it and noticed a knock so tore top end down to find pistion is all scratched up. I dropped it off to get bored (it was .020 over will probably be .040 when done). The blaster has V-force reeds / reed cage, air filter with lid on (4 holes drilled in top). and a shaved head (not sure how much taken off, was told need to run 93 octane). Stock exhaust, and oil injection block off. The carb has a stock pilot 32.5, and I think a 240 main (230 is stock if I am correct). Mixture screw was at 2.5 turns out. I know the only way to get it exact is to run it and check the plug and such but want to know where to start so I don't mess up my new top end. Also The guy ran 50:1 oil mix. To me that is not near enough oil and I will be running 32:1. Thanks for any help.
 
32:1 oil ratio and run a tank of nonsynthetic oil to break in then go to a full synthetic oil after that. I would run a 260-280 but with your stock exhaust that is what is killing your performance. Save some $$ and get that pipe and silencer. Keep checking that plug to make sure you are not lean. once it's warmed up adjust your idle air screw for the highest idle then adjust your idle screw. More than likely 2 - 2.5 turns out is the sweet spot.

This was my last setup: FMF fatty pipe and silencer, .020 Vito's power piston, High compression gasket kit, Vito's advance timing key, V force reeds, K&N filter and lid removed, 280 main jet, needle clip in middle position and that was about it. That blaster pulled so hard from mid to top is was amazing. If I would have changed to tire combo it would have been untouchable for a Blaster....comparing apples to apples of course.
 
I would say the 280 main and 2 1/2 turns is a good start if you get a good exhaust you can go even bigger if you want sometimes i run as big as a 360 main jet
 
Thanks for the replies. When I get it put back together I will through a 280 in it at 2 - 2.5 turns out and go from there. Thanks!