CDI problems at high RPMs?

cf_z · Post by **cf_z** » Sat Aug 30, 2008 7:02 pm

So i noted in anothe thread that i am having problems when i do a high speed run, once im pretty well flying.
It is very odd, once i get to about 60 (sometimes i can get up to 70,..) the bike will stop accelerating, and it is like i am pulling the brakes on and off, or as going from full throttle to no throttle instantly.

I can really only describe how it feels as like downshifting in a car just using the clutch. It will do it 2 or 3 times, then usualy it will let me cruise, but not accelerate much after that. But once i come to a stop i can do it all over again with no accel problems untill it 'brakes' again.

My only guess is that it has to be spark related, as theres no way that the fuel could just stop going in like that. it would at least sputter down.

I have a good spark plug, and a hi-energy coil from daywot. I get bright blue spark when i test it.
My question is, could the old original CDI box just not be able to produce spark at that high of RPMs?

Also, i know when i was taking the alternator type thing off of the crank i know that 2 of the wires going into the clip had about 1/3 of their metal strands broken. Could that be a possibility?
Let me know what you think.

Bear45-70 · Post by **Bear45-70** » Sat Aug 30, 2008 7:09 pm

Sounds more like a bad coil , plug wire, plug or stator than the CDI box. Good spark at cranking speed doesn't mean much except the motor will start. Sounds like something is getting warm and quits working properly. This is a classic bad coil symptom, but I've seen everything in the ignition system fail this way.

DorkoElite303 · Post by **DorkoElite303** » Sat Aug 30, 2008 7:13 pm

Sounds like it's bogging... You should plug chop it after it brakes down the next time and just ride it out to you house like that.

It sounds like your running out of fuel. Your riding at 70mph or whatever at WOT right? then it shuts off?

TWO things...adjust the needle, and you might want to think about getting bigger jets.

cf_z · Post by **cf_z** » Sun Aug 31, 2008 12:59 am

already did that.
It does the same decelleration thing with a 130 main and now a 140 main. Just the 140 main it gets there alot faster

.

And i have a new plug and new coil, and every plug chop ive ever done has been a good brown color...