Ok guys, I've got an 02 blaster, .40 over no airbox lid, k&n filter, TORS removed, gold series fatty pipe, powercore 2 silencer, 280 main jet 32.1 fuel mix wiesco piston kit. "3 hours on rebuild after proper break in." Ran great, better than it ever had on 2 different rides. Started it on the 3rd time out. started fine, ran good for about 20 min then "POP" backfire did it a couple of times and shut it off. Now... It just won't run...I can't figure it out. removed tors properly, compression test was good, airleak test showed a small leak around the reed cage. its fixed now after a new gasket. The bike will start, and idle. I can gradually increase throttle and it will rev up but is seems slow to come back down with a random backfire every once in a while. Idles rather high too. Kinda like its stuck in mid range with no powerband. Ive ripped apart the top end and carb apart numerous times and everything looks good. Swapped reeds and carbs with another blaster and still no luck. O plug chops come back light brown too. Maybe still a little rich. Could there be something in the bottom end that could cause this? I've read up on the forums for quite a while but this is the first post. Finally got stuck and can't figure this one out. Let me know what you think.
What could it be...
- Thread starter randy.winstead
- Start date
Light brown is not lean. You want a cardboard color. If you have confirmed jetting is good, passed leak test, and inspected reeds you have eliminated a lot of things. How many turns out is your air screw? Stock needle in middle? Compression still good? I would pop the stator cover off and ensure flywheel in still properly set on woodruff key.
Is your parking brake sensor disconnected. If not disconnect it.
Is your parking brake sensor disconnected. If not disconnect it.
backfires can be caused by a few things...
reeds which you say are good and sealed ?
an airleak, which you say you fixed ? leakdown tested ?
and a sheared flywheel woodruff key, which may run if the flywheel hasn't moved off the timing mark too far, but won't have any power and may backfire as the spark ignites at the wrong time
time to pull that stator cover and flywheel and give the woodruff key/flywheel a look
reeds which you say are good and sealed ?
an airleak, which you say you fixed ? leakdown tested ?
and a sheared flywheel woodruff key, which may run if the flywheel hasn't moved off the timing mark too far, but won't have any power and may backfire as the spark ignites at the wrong time
time to pull that stator cover and flywheel and give the woodruff key/flywheel a look
Firstly your mods call for no less than a #300 main jet.
Hanging idle, random backfire as the revs come down is a symptom of a lean fuel mix.
Adjust the float level and the idle setting, slip in a #300 main with the needle on the middle clip and do a plug chop at 1/2, 3/4 and WOT.
I don't think jetting is your problem. We run the same exact setup with a 270 main. This is at sea level in colder temps. Did you check the woodruff key?
I will try to check the woodruff key this weekend to see if I slipped timing. Hell, it's hard to find time to ride anymore. But it's almost impossible to get the wife to let me disappear to the garage for a few hours. I Actually have 2 blasters sitting in the garage 1 of them runs great but I'm having some troubles with this one. Thanks for the help, I will update after I check out the Flywheel...
I was thinking sheared flywheel key, maybe loose stator plate if it's ever been slotted for a timing advance mod.
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