Flywheel fin machining

[Minority]

I'm going to machine down the fins on my Indian flywheel and fit a standard cover.
I have heard a few rumours that removing every other fin can be done with no detrement to cooling (maybe improved cooling) and a minimal weight reduction.
I believe MB does this mod to his own scoots.
Anyone out there done this or have any info before I ruin my flywheel .

[camel]

yeah ive read that info myself and actually did it to a long finned flywheel and it ran sweet,altho there is not much weight drop in the removal of the fins if thats what your after as they are only aluminium,the main weight reduction is taken from the steel part of the flywheel.
so is it worth the hassle of fin removal?...

[Minority]

The flywheel has already had a bit taken off the steel part for weight reduction so that wasn't my main aim. I was really wondering if it made any difference to the cooling (and I've just got access to a milling machine so I can play if I want to )

[mickdale]

slightly better cooling but not much loss of weight, imho best is long fin type with every second fin removed and cowling very close to fins

[YAMLAM]

so whats the thinking behind removing every second fin ? running the cowling close to the fins ? can anybody prove disprove any of these theories?

[camel]

probably not.....the theory was it allows more air between each fin...i can see longer fins shifting more air...think of it like a pump or paddle so you dont want a big gap between the cowl so air can be directed out of the area more efficiently

[lozmondo]

I run a tuned SR barrel with every other fin removed and have never had an issue leading to heat seizures.

It works for me

[Minority]

I run a tuned SR barrel with every other fin removed and have never had an issue leading to heat seizures.

It works for me

Did you do the modification yourself and if so what prompted you to give it a try? (glad it's working OK!)

[camel]

this is the info off an old mb electronic ignition guide:
"the standard flywheel comes from the factory with longer fins,to suit the longer fins a new wider flywheel cowling is needed.the idea of longer fins is to aid cooling,we have been told from the man who designed the flywheel that there is too many fins and it dosnt aid cooling at all.A conversion that we have done in the past is to machine off every other fin.This allows more air between the fins and reduces a little weight.Either way a well set up engine seems to cool no different"

[lozmondo]

Oz did mine years back, he's done a couple for me in the past. I cant remember what prompted it, but ive used these flywheels on a Monza 200, standard SX150 and the SR 185