Surfrjag Posted March 16, 2014 Report Share Posted March 16, 2014 Does it rev up after the mid range wall or hit the wall and never climb rpm after that? You have checked yoyr pickup on flywheel? Quote Link to comment Share on other sites More sharing options...
FullThrottle_06' Posted March 16, 2014 Report Share Posted March 16, 2014 im not sure if its the stock needles or not whats the numbers on them and ill look and see i am considering just buying a set of carbs and a intake probably 33 or 35mm pwk I'm not able to get the numbers on the needles right now, but if you have a few extra dollars I would go ahead and suggest buying new intakes and carbs. It would make that motor run like it should. Stock carbs on a setup like that is choking that motor back. I think you would be better pleased if you were to buy bigger carbs. Quote Link to comment Share on other sites More sharing options...
sstaton1983 Posted March 16, 2014 Report Share Posted March 16, 2014 I'm not able to get the numbers on the needles right now, but if you have a few extra dollars I would go ahead and suggest buying new intakes and carbs. It would make that motor run like it should. Stock carbs on a setup like that is choking that motor back. I think you would be better pleased if you were to buy bigger carbs. yep bigger carbs will be easier to tune I bet. Quote Link to comment Share on other sites More sharing options...
gomerkfx700 Posted March 17, 2014 Author Report Share Posted March 17, 2014 Does it rev up after the mid range wall or hit the wall and never climb rpm after that? You have checked yoyr pickup on flywheel? no it never gets past the wall. hits it and just stutters like a 4 stroke on the rev limiter. i haven't checked the pickup either. thats on my list for tomorrow. im going to set the timing on 0 check the pickup and i found my 350-360-370 mains i guess ill start with the 370 and come down from there. Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted March 17, 2014 Report Share Posted March 17, 2014 I have a feeling its the gap. Quote Link to comment Share on other sites More sharing options...
gomerkfx700 Posted March 17, 2014 Author Report Share Posted March 17, 2014 gap between the flywheel and pickup coil? i never really considered that till it was mentioned but i suppose it could be i can't even remember if i set it when i put it together been to long but i would say i just put it on and didn't. Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted March 17, 2014 Report Share Posted March 17, 2014 It happens..but will cuase problems. Like breaking up and not wanting to rev out. Quote Link to comment Share on other sites More sharing options...
blowit Posted March 17, 2014 Report Share Posted March 17, 2014 Let me explain a touch. The pulse generator is a magnetic pickup coil that will send a sine wave of voltage to the CDI upon coming close to and away from something ferrous. That wave or peak voltage is relative to how close or strong the magnetic reaction is. The closer the flywheel gets to it, the stronger the pulse. This does NOT affect spark energy though!! This is merely a trigger voltage for the CDI. But, if you are right at the threshold of required voltage to the CDI, the spark output could be unreliable. HOWEVER, in no way shape or form would you experience troubles that are RPM specific. The problem would seem almost at random. If you get to a certain throttle position or RPM before the problem occurs, that ain't the issue. You may wish to reduce your spark plug gap from the factory .028 to .020. It is common for heavy breathers to snuff the spark, then you think it is rich, lean the jets, and toast the engine chasing the wrong issue. Try that and report back. 1 Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted March 17, 2014 Report Share Posted March 17, 2014 I have experienced troubles that are rpm specific. Mainly upper rpm's but otherwise ran fine. Quote Link to comment Share on other sites More sharing options...
MarineNYC Posted March 17, 2014 Report Share Posted March 17, 2014 Gomer. Same thing happened to me and it was the gap between my flywheel and pickup Quote Link to comment Share on other sites More sharing options...
j stang Posted March 17, 2014 Report Share Posted March 17, 2014 Are you running a stock stator. I have seen ricky stators that would not let the motor rev above mid rpm before. Id checks your ohms on your stator just to be safe. Quote Link to comment Share on other sites More sharing options...
gomerkfx700 Posted March 17, 2014 Author Report Share Posted March 17, 2014 Its stock stator I'm going to check the gap this evening if the rain quits Quote Link to comment Share on other sites More sharing options...
blowit Posted March 17, 2014 Report Share Posted March 17, 2014 More detail this time. In a constant loss CDI, the source magneto coil is coupled directly to the ignition coil through the CDI. The Pulse generator typically has one lead to ground reference, the other goes to an SCR or TRIAC which acts as an AC switch. As the voltage rises from the pulse generator, the voltage meets the threshold (turn on) voltage for the switching device and that device couples the other side of the ignition coil primary to ground reference. As the voltage sine wave from the PG rolls back down or falls, it meets the turn off voltage threshold for the SCR and current no longer flows. The modern CDI is a bit more sophisticated than that due to timing and includes a chipset and crystal to vary timing but in each case, the PG is totally isolated from the output voltage to the ignition coil. This can be further proved on the bench with an oscilloscope and varying the PG gap. Why a Banshee would seem to hit a rev limit with excessive PG gap does not hold water BUT I guess there are possible other reasons for this. As stated, if the PG is right at threshold, something as simple as vibrations from the crank could cause unreliable performance. Anyway. Quote Link to comment Share on other sites More sharing options...
oldskool Posted March 17, 2014 Report Share Posted March 17, 2014 More detail this time. In a constant loss CDI, the source magneto coil is coupled directly to the ignition coil through the CDI. The Pulse generator typically has one lead to ground reference, the other goes to an SCR or TRIAC which acts as an AC switch. As the voltage rises from the pulse generator, the voltage meets the threshold (turn on) voltage for the switching device and that device couples the other side of the ignition coil primary to ground reference. As the voltage sine wave from the PG rolls back down or falls, it meets the turn off voltage threshold for the SCR and current no longer flows. The modern CDI is a bit more sophisticated than that due to timing and includes a chipset and crystal to vary timing but in each case, the PG is totally isolated from the output voltage to the ignition coil. This can be further proved on the bench with an oscilloscope and varying the PG gap. Why a Banshee would seem to hit a rev limit with excessive PG gap does not hold water BUT I guess there are possible other reasons for this. As stated, if the PG is right at threshold, something as simple as vibrations from the crank could cause unreliable performance. Anyway. Your first post was very interesting, but you totally lost me with the more detailed one. Quote Link to comment Share on other sites More sharing options...
gomerkfx700 Posted March 17, 2014 Author Report Share Posted March 17, 2014 Lost me to lol Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.