External Alternator Q's

[FugginZukin]

I am debating the idea of attaching a pulley for an external alternator to the crankshaft on the flywheel/stator side of the motor.

My main concern is that the crankshaft bearings won't be able to take a sideload. Will this even be an issue? Or is the amount of sideload so minimal it won't even matter? The alternator I was thinking of using a Honda Civic or Suzuki Sidekick aternator (55-60 amps). My engine is an 08' CBR1000RR motor.

Thanks for the help.

[nutz4sand]

The crank is already seeing sideloads. The pistons alone are pushing downward on it like crazy.

I do not see a way a mount would load a crank in any bad way just to spin an alternator.

That said you could just hook the alternator to the rear drive. You only need it when you are moving.

[FugginZukin]

Thanks for the info. That makes sense. In regards to balancing: I plan on cutting out the center of the flywheel, machining it down, and welding the pulley to the outer end of this. If this assembly is slightly off balance due to the weld, will the internal balancer be able to compensate for this? The pulley will be bored for a press fit onto the flywheel center before welding and should spin true. Thanks again.

[Damien]

companies make pully kits for busa's to use external dry sump pumps. I think a couple people (yoshi?)on here have used that to run power steering pumps and alternators instead. you may want to see if someone makes something for your motor. or get ideas for how to make your own.

[FugginZukin]

Originally Posted by Damien

you may want to see if someone makes something for your motor. or get ideas for how to make your own.

I've already started on the project and have it all figured out. I just needed to confirm I wasn't going to grenade my motor once I get it running. Here's a couple of pics of what I have done so far:







I have to turn down the center part of the flywheel that was cut out and bore the pulley I am going to use. I then need to weld the pulley to the flywheel center, and weld the seal housing to the cover.

[yoshi]

not familiar with the motor your using, but the Busa is easy to do, no cutting required......

[FugginZukin]

Badass, nice work. What alternator is that and what is your crank/pulley ratio? Also, where did those pulleys/belt come from? Thanks.

[yoshi]

Originally Posted by FugginZukin

Badass, nice work. What alternator is that and what is your crank/pulley ratio? Also, where did those pulleys/belt come from? Thanks.

denso race alternator

ratio is gonna depend on your motor vs alternator speed, different motors and different alternators have different min. and max limits, so you will set the ratio up off that.

They are just cog pulleys and belts, lots of places have them, just look the up for your area, or search the online. I've got them from multiple places, always looking for better deals...

[K-fab]

Originally Posted by FugginZukin

I plan on cutting out the center of the flywheel, machining it down, and welding the pulley to the outer end of this. If this assembly is slightly off balance due to the weld, will the internal balancer be able to compensate for this?

NO!!! NO!!! NO!!! That's just asking for poof-kaboom.

The balancer is designed for the parts in the engine as they come from the factory. It's there to deal with the engine's components as a whole and how they work with each other. Position of the crank in relation to the pistons, pistons in relation to each other and such. The engine's components are all supposed to be as close to each other in weight (pistons, rods) as possible from the start. Crank is dynamically balanced too.

Ending up with a flywheel that's out of balance is like having a tire that's out of balance. There's weight in the wrong spot swinging out around some point (center of the crank) and it's pulling all the way around it's little path, knocking everything else out of balance.

If it's bad enough (worst case scenario), it could actually fatigue and break off what ever it's attached to if the balance is out enough. - or shake the engine (and your teeth) to the point of failure.

If you mess w/the flywheel at all, you'll need to have it balanced once you're done. Not sure who can do that - but it is possible to do.

[FugginZukin]

Originally Posted by K-fab

If you mess w/the flywheel at all, you'll need to have it balanced once you're done. Not sure who can do that - but it is possible to do.

Thanks for the info. I will have to call around and see if I can find a local machine shop that can balance it. Hopefully they can balance something this small.