03 blaster issues

Angryinch

New Member
Jan 28, 2016
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Hey guys, picked up a 03 blaster for my girlfriend to ride around on while we're at the track, I ride on 2 wheels hah. Anyways, this thing is a headache.. I always work on my own stuff and have since I was a kid, maybe I'm just missing something here but this is what I'm dealing with.

Fires right up, rough idle, full revs in nueatral but barely cones off the limiter when I put it in gear and give it gas, it also wants to die if I'm not full throttle. The limiter screw is all the way out so that's not stopping me, "tors"system has been terminated by me the right way and hooked back up, good compression, clean spark plug, good reeds and cage, cleaned carb and jets, flywheel and stator are in good shape. I diconected the "parking brake" cause I read that it was giving some people issues like I'm having. I HAVE NOT checked the gap on the plug but it shouldn't be the issue here. It's running the stock 230 main jet with a pro circuit pipe on it as well, but even if it needed a 250 it should still get up and go but Spudder along the way.. does anybody know what to check next?
 
how long you been running it with the stock 230 way too small main jet for that pipe ?
could have damaged it already ?

check compression, should be at least 110 psi at the minimum, 120-130-ish optimal.

leakdown tested ?
http://www.blasterforum.com/threads/how-to-perform-a-leak-down-test.44653/
http://www.blasterforum.com/threads/leakdown-testers.55015/


check/set float height: http://www.blasterforum.com/threads/float-heights-and-how-to-adjust-them.50565/
tune airscrew w/ stock 32.5 pilot: http://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/

needle clip in the middle slot

buy 270 thru 310 main jets, start large and plug chop down
http://www.blasterforum.com/threads/how-to-plug-chop.53237/
 
how long you been running it with the stock 230 way too small main jet for that pipe ?
could have damaged it already ?

check compression, should be at least 110 psi at the minimum, 120-130-ish optimal.

leakdown tested ?
http://www.blasterforum.com/threads/how-to-perform-a-leak-down-test.44653/
http://www.blasterforum.com/threads/leakdown-testers.55015/


check/set float height: http://www.blasterforum.com/threads/float-heights-and-how-to-adjust-them.50565/
tune airscrew w/ stock 32.5 pilot: http://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/

needle clip in the middle slot

buy 270 thru 310 main jets, start large and plug chop down
http://www.blasterforum.com/threads/how-to-plug-chop.53237/
Not sure how long it has been run on stock 230 main, just picked it up needing work. Compression is good, floats good, no vacuum leaks either. I have yet to gap the plug and check the needle clip. Hands got cold and dinner was ready hah. I will pick up some jets and give that a shot, thanks for the reply.
 
free flowing gas from tank to carb.
make sure gas cap is venting properly unscrew it a lil to check.
ngk b8es spark plug
if idle is ruff either
low compression
starving for gas/air

have you tried adjusting idle/airscrew settings?
 
free flowing gas from tank to carb.
make sure gas cap is venting properly unscrew it a lil to check.
ngk b8es spark plug

It is getting fuel, what gap am I looking for ? Seen a few different recommendation's with the pipe it's got on it. And no, just seen some guys where having issues with the parking brake so I just unplugged it hah.
 
Did a little more tinkering today, found that the rear brake rotor was hanging up on the shroud. Somebody whacked something hard cause it was rubbing pretty good. Took that shroud off and it helped a lot, but now it seems I do need to do some jetting. Found some jets in a parts box and am wondering what pilot I need to run a 260 main? I got a 32.5..
 
Welp, borrowed my buddy's compression tester and found out mine was junk. Only got 100 psi with a brand new snap on compression tester. Any good places to find a cheap top end??
 
Welp, borrowed my buddy's compression tester and found out mine was junk. Only got 100 psi with a brand new snap on compression tester. Any good places to find a cheap top end??

just have that cylinder bored to fit a new piston, if there's nobody local you trust and has experience with mx/atv cylinders ?.....................
http://kenoconnorracing.com/
worth the cost of shipping to know it's done correctly
 
I'm not looking for more power, just need a fresh top end, stock bore should be just fine unless you're trying to tell me different?? If the cylinder is junk I'll just buy a new one.
 
yep, I'm tellin you different.
with that low of compression, both the piston and cylider walls are worn beyond spec.
you'll need to have it measured, the cylinder bored/honed to clean it up and buy whatever overbore size piston the shop tells you is needed, usually just one size bigger for wear, or more for damage.
no need for a cylinder, you have 8-ish over bores on that cylinder.
over boring adds no extra power but will restore it back to stock power.

$80 - $100 for piston depending on brand
$65-ish for bore/hone depending on where
+ top end gasket set