Charging coil possible on Predator 420 with billet Flywheel??

Turbo420

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I'm looking into getting a billet flywheel for my 420 predator but I have to have a charging coil. It would be difficult to run my fuel pump and oil pump system off just a battery and would be stuck with limited run time. Ive looked at getting an external alternator from a tractor but thats extra machining, fabrication and cost. Is it possible to modify a billet flywheel like an ARC one to still use the factory charging coil ?
 

mckutzy

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You need them to have magnets installed by them... As it needs to be balanced precisely with them...
Don't try to modify it as it then will be dangerous to use...
 

Turbo420

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I called ARC and they dont offer any services to mount magnets so my only option would be a local machine shop to mount and re balance it. I just dont understand why companies would build aftermarket upgraded parts where you have to remove things like your charging system.
 

mckutzy

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I'm not sure why either...

To get it mounted and re balanced it'll be expensive..
Who knows how ARC balances theres.. w/wo the crank, con-rod/ piston weight, ect...
It all factors in what they need for balance.
 

Turbo420

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I'm ok with a machine shop doing it right. I dont have much of a choice at this point other than fabricating an external pulley driven alternator or running a larger heavy battery which will still give me limited run time.
 

karl

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I dont have much of a choice at this point

Any reason for the billet flywheel? Are you also using a billet rod?

If your rolling with factory cam and springs, I would not worry about the flywheel too much.

Much more obstacles to overcome first.

Or if your just trying to spool a turbo too big for a 420cc,

Just step up to the 670cc twin, with stock internals. Should not cost much more than the
420+ billet flywheel + billet rod, and two cylinders should get a decent turbo going.
Did I mention pressure lube?
 

Turbo420

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Already have a cam , billet rod , springs, pushrods, lifters. All should be good for 7500rpm. Haven't pushed past 5000rpm because of the stock flywheel. Had a 670cc but it was impossible to fit on the frame. This is a mini drag bike after all. Not a go kart.
 

karl

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Already have a cam , billet rod , springs, pushrods, lifters. All should be good for 7500rpm. Haven't pushed past 5000rpm because of the stock flywheel. Had a 670cc but it was impossible to fit on the frame. This is a mini drag bike after all. Not a go kart.

Right on. Did not think this was intended for a bike.

How many amps do you need to run the pumps?
 

Turbo420

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The oil pump for the turbo setup is rated at 1-2amps. My current fuel pump is a diaphragm vacuum operated pump which will not be addiquit for the turbo. Need a higher pressure electric pump which ive yet to find. Along with an adjustable fuel pressure regulator with a boost reference port. Everything is oversized for what im doing and will use too much power.
 

vpd66

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I'm not sure why either...

To get it mounted and re balanced it'll be expensive..
Who knows how ARC balances theres.. w/wo the crank, con-rod/ piston weight, ect...
It all factors in what they need for balance.

These engines are internally balanced. So to answer your question how ARC does it is they just neutral balance the flywheel. That way it doesn't affect engine balance. Same with the clutch or torque converter you put on the output shaft of the crank. It is neutral balanced.
Installing charging magnets to a flywheel brings up several challenges. Since they have to be mounted to the back of the flywheel because the charging coils mount under the flywheel makes it very difficult. Plus I'm sure this would bring the rpm limit of the flywheel back down. The best option if you need a charging system would be to mount a belt driven alternator. Look into John Deere Gators. Some of them have very small external alternators.
 
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