Keep fouling plugs

[Brett]

ok finally got off me ass and threw some money around to no avail.
got generator? coil rewound $180aus, got slightly brighter spark but didn't fix problem.
noticed slight weepage around LH crank seal but is less than 9 months old as replaced all seals+bearings when rebuilt.
bought another 500 for $500aus with 75% of motor (yes am looking for flywheel, carb boot, reed block, clutch assy, kicker) and wacked on the black box (wires had different plugs 90 vs 91) got it runnin but still no good.
Marked timing onto flywheel and ran  bike and it shows 16 degrees but when slowly revving up it starts its misfiring and timing goes + or - 30 degrees from TDC. if held full throttle for long enough for it to pass this stage timing goes back t roughly 16 degrees.
its got me stuffed.
By the way the 90 model cylinder without center powervalve looks like it has some high horsepower potential good for dirt drags.

[KXcam22]

Brett,
  Just a thought. The -30 tells me it is firing late. Any chance you could try another pickup. Might be failing and cause late response. Hope this helps. Cam.

[Brett]

OK finally got the bloody thing running.
It turned out to be the pickup coil.
I put my other one on and started it, wacked the timing light on it and it stayed within +-5 degrees all way up through rev range.
Went for a ride with 3 2006 yamy 450's and pissed on em in the numerous drag races we had, but i have to say after riding two of em they have fantastic handling which i am now gonna try to replicate. but all in all i love the girl again.

[dennis]

I have the same problem with plugs. I've put in
Vforce reeds, rewound the stator, new stock coil, fmf pipe, and changed the needle many times. The problem I'm thinking is in the ignition, maybe a weaker than should be spark. My bike starts good and runs strong, just dirties up plugs. very frustrating

dennis

[kx666]

I have the same problem with plugs. I've put in
Vforce reeds, rewound the stator, new stock coil, fmf pipe, and changed the needle many times. The problem I'm thinking is in the ignition, maybe a weaker than should be spark. My bike starts good and runs strong, just dirties up plugs. very frustrating

dennis

what plug are you running? you may need to go up a heat range.
if your getting a good spark you may want to look at jetting. jetting needs to suit temperature, humidity, altitude, pre mix oil, motor changes and even ridding style and weight.