I am going to re build my tv 175 motor with g.p crank etc,my question is do i need to go for a lightened flywheel ,i hear heavy wheels rob power,any thoughts please?.
Thanks Ian
lightened fly wheel yes or no??
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idc1967iow
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bristolmod
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lightened within reason Ian. Too light and your tickover is very lumpy. Having said that your acceleration is increased as less power is going to spool-up the flywheel mass. Most noticeable in 1st, but decreasing proportionatly in 2nd 3rd and 4th.
BTW are you keeping the Mugello on it?
Chris
BTW are you keeping the Mugello on it?
Chris
Scootering since 1968.
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warts
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Where is this "robbed" power supposed to go?
Just trying to remember conservation of energy/momentum stuff from uni. It was a v. long time ago, but the universe hasn't had a rebuild since.
Surely the power, converted into momentum is still there? Waiting to be unleashed?
Two advantages really,
less stress in the magside mainshaft as the engine works against the lower inertia, and therefore less likely to shear mainshaft on earlier models.
The revs will pick up quicker when on the stand so you can impress your mates.
In practice, on the road this effect is swamped by the total load/drag - aero, road etc. being so much more massive. The stored momentum comes back into play on real roads, a bit like the ex F1 KERS systems being introduced on highend cars.
Some old F1 race team or other did experiments with different weights of flywheel. The drivers weren't told which was which. All posted better times with the heavier flywheel.
Some people like the harsher, lumpier effect, makes it feel like a real racer, others prefer the smoother style.
It is of course possible that designed as a shopping trolly, lambrettas had far too much flywheel effect once any sort of tuning is applied.
Just trying to remember conservation of energy/momentum stuff from uni. It was a v. long time ago, but the universe hasn't had a rebuild since.
Surely the power, converted into momentum is still there? Waiting to be unleashed?
Two advantages really,
less stress in the magside mainshaft as the engine works against the lower inertia, and therefore less likely to shear mainshaft on earlier models.
The revs will pick up quicker when on the stand so you can impress your mates.
In practice, on the road this effect is swamped by the total load/drag - aero, road etc. being so much more massive. The stored momentum comes back into play on real roads, a bit like the ex F1 KERS systems being introduced on highend cars.
Some old F1 race team or other did experiments with different weights of flywheel. The drivers weren't told which was which. All posted better times with the heavier flywheel.
Some people like the harsher, lumpier effect, makes it feel like a real racer, others prefer the smoother style.
It is of course possible that designed as a shopping trolly, lambrettas had far too much flywheel effect once any sort of tuning is applied.
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Adam_Winstone
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I tend to fit light flywheels on any serious performance big cc motor simply to make it less likely to twist the crank. I'd rather fit a light flywheel and not have to have the crank pin welded, which helps for crank rebuilds in the future.
As stated above, light flywheels help a motor's revs to rise quickly but they don't give any real performance gain when holding steady speeds when the revs are already higher.
In light of the above statements, I see fitting a light flywheel as a reliability benefit for big rather than a performance gain. Please note, this relates to the fact that you've said that you are fitting a GP crank, whereas EVERY/ANY motor running an LI/TV/SX weak taper crank would benefit from fitting a lighter flywheel.
Adam
As stated above, light flywheels help a motor's revs to rise quickly but they don't give any real performance gain when holding steady speeds when the revs are already higher.
In light of the above statements, I see fitting a light flywheel as a reliability benefit for big rather than a performance gain. Please note, this relates to the fact that you've said that you are fitting a GP crank, whereas EVERY/ANY motor running an LI/TV/SX weak taper crank would benefit from fitting a lighter flywheel.
Adam