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Discussion Starter #1
hey y'all have had my 748 for awhile now and was looking into the removal of the flywheel mod. has anyone done this and how is the bikes ridability?
985822
 

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Do a search. Plenty of opinions and experience to ponder.


Also, be aware that ...

A lighter than stock flywheel presents an increased risk of damage to the sprag clutch mechanism. During startup, the sprag clutch first engages and then the starter motor spins up the engine. The more inertia (weight) of the flywheel, the more total angular momentum that the rotating engine parts have, so the more resistant to a kickback from a misfire (fairly common) during startup. If the backward impulse from the misfire (kick-back) exceeds the motor’s forward angular momentum the motor changes rotational direction. If this happens while the sprag is engaged it’s bye-bye sprag.
 

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Discussion Starter #4
Do a search. Plenty of opinions and experience to ponder.


Also, be aware that ...

A lighter than stock flywheel presents an increased risk of damage to the sprag clutch mechanism. During startup, the sprag clutch first engages and then the starter motor spins up the engine. The more inertia (weight) of the flywheel, the more total angular momentum that the rotating engine parts have, so the more resistant to a kickback from a misfire (fairly common) during startup. If the backward impulse from the misfire (kick-back) exceeds the motor’s forward angular momentum the motor changes rotational direction. If this happens while the sprag is engaged it’s bye-bye sprag.
Do a search. Plenty of opinions and experience to ponder.


Also, be aware that ...

A lighter than stock flywheel presents an increased risk of damage to the sprag clutch mechanism. During startup, the sprag clutch first engages and then the starter motor spins up the engine. The more inertia (weight) of the flywheel, the more total angular momentum that the rotating engine parts have, so the more resistant to a kickback from a misfire (fairly common) during startup. If the backward impulse from the misfire (kick-back) exceeds the motor’s forward angular momentum the motor changes rotational direction. If this happens while the sprag is engaged it’s bye-bye sprag.
cool thank you for the insight will be leaving the flywheel alone since i only ride on the street.
 

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It will also idle better with flywheel left stock.
 

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Pull the flywheel and enjoy! It's one of the better mods on the older 748s and it is free.The engine feels smoother and it "feels" like you gained a few HP.

I removed mine at 15k miles, and up to the 32k mile mark when I totaled it, I never experienced and issue. Just be sure to red locktite the flywheel nut and torque to spec.

Sprag clutches fail on standard flywheels as well. If you don't like the bike with the flywheel off, put it back.
 

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i don't believe the negative from above. i feel the starter clutch failures are more from the act of removing and replacing the assembly (just from being disturbed), not the lack of flywheel weight. and if the tuning is right, it should idle and run fine.
 

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I'm coming from a 996 perspective, where you can't remove the flywheel completely.
I went with the very light weight Nichols version ( I think about 9 oz. ) many years ago on my first 996. At this point my engine was essentially stock, and I loved the difference it made to overall vehicle dynamics. Application was pretty much exclusively street use
It really livens up the throttle response. Responsiveness. That's what this mod is all about and i'm very enthusiastic about the difference it makes.
For me it even made the bike feel lighter on it's feet during quick transitions. Some people have poo poo ed that this effect could be felt, which is fine. I could feel it and that's what matters to me. On the 996 we are talking about a 3lb difference of rotating mass..
On my current engine build I'm having a stock flywheel lightened as much as it can be, which will be a half way point between stock and the Nichols. I had a sprag go bye bye. Was it because of the super light flywheel? Perhaps. So I'm taking a slightly more cautious approach this go around
 

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Have the stock flywheel cut down to 1/2 weight and you will also be fine. Yours is probably 4lbs now and somewhere around 2 lbs gets you stock reliability as well as faster spin up/deceleration. One of the best low buck mods IMHO. I am not a fan of too light for long term use but thats my preference. I find the 2lb flywheels to be a sweet spot.

I have never seen a increased sprag wear due to a light weight flywheel much more often to poorly tuned bikes or older models that were prone to firing early (916,851 p8 or p7 ecu). or aftermarket race ecu's (nemesis, microtec) that are set up wrong. Street bikes running later ecus with lightened flywheels should not be spit back stalling. If they are spitback stalling find the cause and fix it.
 

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it's not there for balance, it's there for rotating mass. you remove the alternator cover, remove the flywheel assembly, undo the screws that hold the outer ring on, put outer ring somewhere else, refit all parts. torque and loctite the big nut.

the 4v engine went from single phase to 3 phase alt for 99 model year.
 
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