Yamaha blaster carb bowl drains while driving?

0208jmh

New Member
Oct 12, 2020
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I Just bought a blaster and the previous Guy tuned it, it has a hgs exhaust system and a 28mm oko carb with a 150 jet

It ran pretty poorly when i got it, i removed the cover over the air filter and that made it go like hell, it pulls the front wheels up in third gear..

The problem is when it hits the powerband it completely dies out for a while until i let it go back to idle, it sounds like it runs completely out of fuel for a while,
After that it starts all over again, ive tried a bigger diameter fuel hose and removed a little inline filter which made it better but it still bogs down, also tried a bigger jet and adjusting the float and airscrew but that Did made it better but doesn't solve the problem completely

Did anyone have this happen before
Any suggestions??
 
Have you done a plug chop to see where your jetting is? Removing the air box lid will lean it out some as you have more air flow.

Is the tors deleted?
 
Have you done a plug chop to see where your jetting is? Removing the air box lid will lean it out some as you have more air flow.

Is the tors deleted?

Tors is deleted, havent done a plug chop yet but the electrode on the plug was pretty black
 
Tors is deleted, havent done a plug chop yet but the electrode on the plug was pretty black
May want to clean or change out that plug cap.
Is float hight set correctly? Are you running the stock carb? If so is the washer under the main jet installed?
With the fuel line off the carb when petcock is turned on is there a good solid flow on both regular on and reserve? There are very fine screens for both on and reserve.
Also make sure your gas tank cap us venting. There is a ball in there that rusts up and gets stuck. It can be taken apart and cleaned.
 
Also check that float valve is clean and not sticking.
I've tried adjusting my spark gap and it ran way better with the gap all the way down to 0.15 but it still bogs after a few seconds in powerband, starting to think it might be a faulty plug or something with the ignition
 
Tried a b8 and b9, not alot of difference, had some backfires yesterday i'm starting to suspect te reeds
Backfiring is ussualy the reeds or timing key sheared..
Probably reeds
Stick with the b8es plug .028-.032 gap if i remember correctly
 
Backfiring is ussualy the reeds or timing key sheared..
Probably reeds
Stick with the b8es plug .028-.032 gap if i remember correctly
The reeds had a little bit of a gap so i flipped them around and was not able to see any light passing trough anymore, problem still there, i dont have any idea what it could be anymore apart from the ignition, this is extremely frustrating
 
Remove plug cap from wire and Ohm it and coil separately. Cap should be 5k, you’ll have to look up coil value. Cut 1/4” off wire, install cap with bit of dielectric grease. After that check that coil mounts are clean bare metal and ground wire is clean and bare, add dielectric grease