it's a 89 it idles perfect. goes from idle to mid perfect but it doesn't  want to rev out it studders as long as i hold the throttle past mid. motor has following brand  new,

big bore sleeve installed.
ported
3 mill stroker/stuffer crank.
new 240 vito's piston.
all new gaskets,seals
used 35mm pj carb.
used prodesign intake
adapter/reed spacer(1/2 inch)
used reeds but not stock.
stock exhaust without silencer right now.

any advice would be nice. i think its either carb main jet or electrical somewhere maybe.it's not tors because it's not hookup.  

What size main jet you got? give some info on the carb  

cutting out or stuttering is a sign that it is too lean.
try turning the fuel/air mixture screw on the carburetor to the left 1/4-1/2 turn.
see if this doesn't help you out.  

the main jet size i have not found out yet. the carb was on a race type blaster motor before i bought it. so i would think it's fairly close but i will pull the carb  probably by monday. the carb is a 35mm keihn pj. i do know the slide is what they call a 6.0 grade/angle. sticker on the side says race use only. this is all i know until i pull the carb.  

Wolf,

the only adjustment this carb has on the outside is a small inset screw on one side towards the bottom of the air intake/filter side of carb. right now it's set at almost 1 full turn. also the slide was set at middle when i got it and i tried moving the needle up one notch(needle would be 1 notch lower in mj) which seemed to help get a little more rpm's before it studders  which to me means it would be even leaner than the middle notch right? or am i just thinking it runs better than before? this carb doesn't even have a idle screw you can only adjust idle at carb cable cap adjustment.i'll try turning back 1/2 turn on that adjustment screw and see if it helps. i'll respond back if it helps or not.  

wolf,

I think that fixed the problem. i turned the screw all the way in then 1/2 turn out seems to run alot better  and doesn't seem to studder. one thing though now is after this adjustment to where i can actually give it some gas i found out i need clutch plates with this motor combo. plates are slipping pretty good when i get on it now. thanks  

hey i have a 1989 blaster and i want to make it keep up with the 400s and the 450s  

what can i do to make my blaster keep up with the 400s and 450s  

obsidian you can get a really good clutch kit from www.rjatv.com at a really good price.

the clutches he sells are better than stock and cheaper.  

well the blaster will outrun a stock ltz400 at least it does my buddys' ltz400

but if you bor it out .40 over you'll have no trouble keeping up with them.  if you put a 240 big bore kit on it you'll flat out blow them away.