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Anyone tried this? Is it even possible with the 929/954 flywheel? Was looking to take mine in next week. They told me to bring it in before they could tell me whether or not it would be possible. Just trying to save time and work if it will not be able to be done. Thanks!
 

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My understanding is that you get quicker (better) throttle response as well as a gain in power. Rumor is, for every pound of rotating mass you lose, it is equivalent to 7-8 pounds of weight. Also, the flywheel being connected to the crankshaft, I think it could help significantly. I've spoken to racers that have had the flywheel completely removed and said there is a huge difference. And to lighten and re-balance is only about $75! Cheap mod for more performance.
 

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Jake : My understanding is that you get quicker (better) throttle response as well as a gain in power.  Rumor is, for every pound of rotating mass you lose, it is equivalent to 7-8 pounds of weight.  Also, the flywheel being connected to the crankshaft, I think it could help significantly.  I've spoken to racers that have had the flywheel completely removed and said there is a huge difference.  And to lighten and re-balance is only about $75!  Cheap mod for more performance.

Yep, a lightened flywheel has a number of benefits (as well as detractors), especially on a street/race bike.
 

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Jake : 2OHOH2954,
Do you know if shaving the flywheel will affect the charging system?
Not having seen the guts of the system (does the outer flywheel act as the rotor, and if so, will shaving the flywheel increase the distance from the stator? if so, then yes), I can't say. There are other ways of lightening it, such as drilling, replacing it with a lighter material, etc. Money's usually the limiting factor.
 

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Discussion Starter #8
2OHOH2954,
Thanks for the quick reply.  I don't think they would touch the inside of the rotor, but probably the outside.  I wouldn't want them to mess with the inner spacing.  I was thinking since you lose metal you may lose magnetic effect.  Not sure though, and that's why I ask.  So even if it is shaved from the outside, you will still lose the magnetic effect.  I definately was going to ask them to drill some more holes into the flywheel or maybe bore out the holes that are already there (on the back of the rotor where the bolt holes are).  

Anyone else have an opinion or recommendations about what is stated above?
 

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The only problem with this is that the flywheel and crankshaft are balanced as a unit at the factory.  You have a 1 in 10,000 chance of getting the balance correct after you have the flywheel turned without removing the crank and having the whole unit balanced.  The end result (without balancing) can be anywhere from 'a bit more vibration' all the way to total 'self destruct'.  

I have had this done on several of my bikes and there is a small (~2 HP) gain to be realized, but for the time and money required to tear down the motor and have the crank and flywheel balanced, it certainly isn't any '$75.00' performance mod.  You also loose big time on launching the bike, as the flywheel is very important in terms of forward gyroscopics and rolling torque.  

I would only consider this if you were doing pistons, rods and knife edging the crank, as the small gain is really only part of a much bigger (and much more expensive) package.
 

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Discussion Starter #10
Abtech,
Thanks for the reply. Unfortunately you have dimmed my hopes. But the truth is what I was seeking. As mentioned in another thread, I do plan on having crank work done. I guess the stator should be sent in with the crank so they can do the whole unit, correct? You mention 'knife edging,' what is that? Do you think I will notice a gain by doing these two things without touching the pistons and rods?
 

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Jake, not trying to be funny, but... if you're doing all that, you might as well throw in some forged/swained components, get the whole thing extrude-honed, and toss in NO2 and/or a turbo, and get it dyno-tuned. THAT would be one fast ride
 

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Discussion Starter #12
This is true. I could go that far, but my wallet and wifey won't. I figure this is relatively cheap. And doing the labor myself keeps me occupied with my hobby and is very cheap. All in all, with the crank and flywheel, I'm thinking (hoping) around $400 max. For what I hope to be worth it, I guess we'll see...
 

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Knide edging is where the crank weights are ground down to , ummmm, well a knife edge. This has a couple of advantages. The first is obvious and that is the reduction in rotating mass due to the material removal. The second is more subtle, but for a fast bike, very important. Regardless of the type of oil (dino, synth blend or full synth) you use, there is a considerable amount of resistance presented by the oil to the crank weights as they turn in the 'bath'. Knife edging reduces this resistance as well as the cavitation that results from the rather blunt leading edge striking the surface of the oil as the crank rotates.

On my VFR racer, knifing the crank resulted in 7 HP on the top end. Turning the flywheel gave me an additional 2 HP, but only after the HRC rods and a complete bottom end balance job could the bike actually be run to redline. About 3K for 9 HP, but when you have done everything else, 9 HP is nothing to be sneezed at . . .
 

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abtech : ...there is a considerable amount of resistance presented by the oil to the crank weights as they turn in the 'bath'...
AKA windage losses.
 

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I always thought 'Windage' was what 90% of what I read on this forum boils down to . . .
 

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abtech : I always thought 'Windage' was what 90% of what I read on this forum boils down to . . .  

That would be 'fartage', and would make up 99%
 

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Re: knife edging etc. a lighter flywheel will make it feel more like GSXR to rev, but why bother unless going the whole hog?

But the crank does NOT turn in a 'bath' of oil - the oil level is below the crank in a modern bike engine (I'd be very very surprised if Honda designed the blade differently).
 
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