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Light Flywheel?
Posted: Sat Jan 20, 2018 10:48 pm
by Lamaddict
So it’s a close to standard motor and was wondering if a lighter flywheel might get me a slightly improved top end? At the minute I have a SIL one on but thinking of the AF Rayspeed lighter one.
Re: Light Flywheel?
Posted: Sat Jan 20, 2018 11:30 pm
by drunkmunkey6969
It won’t help on a standard motor. Leave as is....
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Re: Light Flywheel?
Posted: Sun Jan 21, 2018 1:42 am
by johnny650
what weight is a 'light' flywheel ?
I just bought an electronic flywheel which weighs 2Kg and my original LI150 is probably close to 2.5Kg although I haven't weighed it yet. I read somewhere that AF Rayspeed sell one weighing just 1.2Kg
Does anyone have any recommended weights and application advice ?
Light Flywheel?
Posted: Sun Jan 21, 2018 10:51 am
by drunkmunkey6969
Read this:
https://www.scootering.com/scootering-c ... ng-part-3/
Darrell Taylor did a 6-part series called Bang for Buck Tuning. All 6 parts are available on the site now, part 3 (link above) covers the 2.6kg (heavy) & 1.85kg (mid) weight flywheel tests.
Up to 5400rpm there was no discernible difference between the two, over that there’s was 1hp difference.
This particular test would suggest that lighter flywheels come into their own much better on higher revving engines, than they do on standard/low revving engines.
Re: Light Flywheel?
Posted: Sun Jan 21, 2018 3:21 pm
by Lamaddict
Thanks Drunkmonkey,
I just thought lighter the better and it would increase revs no matter what. Looks like there’s more science behind it.
Re: Light Flywheel?
Posted: Sun Jan 21, 2018 3:58 pm
by johnny650
drunkmunkey6969 wrote: ↑Sun Jan 21, 2018 10:51 am
Read this:
https://www.scootering.com/scootering-c ... ng-part-3/
Darrell Taylor did a 6-part series called Bang for Buck Tuning. All 6 parts are available on the site now, part 3 (link above) covers the 2.6kg (heavy) & 1.85kg (mid) weight flywheel tests.
Up to 5400rpm there was no discernible difference between the two, over that there’s was 1hp difference.
This particular test would suggest that lighter flywheels come into their own much better on higher revving engines, than they do on standard/low revving engines.
Thanks for the link. I'd forgotten that it was covered in that excellent series B for B.

Re: Light Flywheel?
Posted: Sun Jan 21, 2018 9:12 pm
by Scooterdude
Be wary of the lightweight ones from Rayspeed, I bought one last year they don’t match up with the cowling and the pickup rubbed on the inside.
Re: Light Flywheel?
Posted: Tue Jan 23, 2018 2:59 pm
by Mark97
Many years ago when I raced Group 4 using one of the early AF Ducati flywheels we did a dyno test using a standard road going stator plate and then replacing it with one that had just the Pick-up and the LT coil on it. The other redundant "lugs" had all been removed.
The theory was you would get less magnetic drag - and the dyno proved this - adding an extra 2hp all thru the power curve.
Re: Light Flywheel?
Posted: Tue Jan 23, 2018 3:37 pm
by patrick
Be wary of the lightweight ones from Rayspeed, I bought one last year they don’t match up with the cowling and the pickup rubbed on the inside.
I fitted one and had neither of these problems.
Yes the fins are short so you might want to fill the gap between the ends of the fins and the cowl to improve cooling but that's it.
Re: Light Flywheel?
Posted: Tue Jan 23, 2018 11:38 pm
by Doom Patrol
I've found the mid weight flywheel to be very good and a nice compromise. You won't go any faster, but it does make the engine seem more lively. So you probably think you are.
