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about on wits end with this thing a little help please


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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.

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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.
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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.

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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. 

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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. 

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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.

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