Dirt Bike guys step in, carburetor guys too... Backfire/startup issue (also stalling)

I hear ya, you know the old saying. When you have a problem check the last thing you fucked with. :mpd: Does the bike still have the stock CDI on it? It’s mostly the hard cranking issue that makes me lean toward an ignition issue. It acts like it is trying to fire too soon.

Could advancing the cog that goes to the starter when the case cover was off have anything to do with it? Is it position sensitive?

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Also, if it’s charging at 15.x volts while running, is that a big deal?

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I’m running non oem stator and rectifier

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i was under the impression that anything over 14.7v would cook a battery

(i just did a whole slew of reading on this topic a week ago when i had to diagnose the charging system issue with my newest harley)

Maybe I’ll go test the battery but seems to be holding up just fine… Could it fry my starter?

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Next question… I ordered both stator /rectifier online from the same place… Both are aftermarket. (if I throw a stock rectifier in the bike do you think the volts would drop back down? Can the stator itself cause higher voltage or is it completely dependant on the rectifier l

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now i dont claim to be an expert by any means
but
what i grasped from my reading was that if the stator is working properly it will be pushing out AC voltage in a certain range (thats generated via the spinning magnet and stationary coil setup) and its the regulator/rectifier’s job to change that to DC voltage and keep it in a safe charging range for the battery when the bike is running (not lower than 13.0v typically and not higher than 14.7v typically)

what is the ACv reading on the stator output?
what the batterys DCv when the bike is off?
whats the battery DCv dip down to when you put the starter load on it?
is that 15.0v the lowest DCv reading at the battery while the bike is running?

I’ll have to check that next time I tear into it. I just remember it being 14.65 volts at idle… Sometimes as high as low
15s iirc

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I hate motorcycles… Why can’t they make a 300 lb, 60 Hp, bulletproof, warrantied, fuel injected, motard !?

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im really curious what the battery reads under starter load

i would say if it drops below 10v then replace the battery.

read one of my last posts in the vintage motorcycles thread
i just tracked down the issue of my slow to crank issue which was a voltage reg and battery.

you mentioned it was a slow first crank when you hit the starter button sometimes. my battery dropped down to 9.6v and it was just too weak to spin it cause my VR was on its way out and would only send 12.7v to the battery while running (basically creating a weak battery)

at idle your reading seems fine but i just wonder if its hitting 15v could it produce a similar weak battery issue by slowly boiling the battery

also.

dont forget to clean your carb. lol.

OK OK OK… Thanks.

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Why would you clean the carb if the seafoam fairy will magically fix everything?

Yeah, that could definitely be boiling that battery. Is 15v at idle? What’s it come up to if you Rev it up a bit?

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Seems normal. Cars are mid to high 14v.

Just checked it all again…
Bike off. 12.8 v
Bike on 14.4 to 14.5 volts no matter how I Rev it.

When I pushed the starter button it fired up so quickly that it didn’t show a noticeable sustained drop in voltage.

It was high 14s last time I did this thought… Odd.

everything seems normal there

Is that bike on with lights on?

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Bike on. Lights on. [ATTACH]32198[/ATTACH] damn you guys.

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lots of carb cleaner and compressed air