flywheel machining :my way

[timucin]

i found these pics from web and decided to do the same with my 3b flywhl:

[timucin]

other side:
planning to go 2cm from sides to center.1 cm deep

[timucin]

is this a common way to lighten flywheel?
how many kg can i gain?
is it worth the try or i should leave it as is?

[91_S2]

Incorrectly lightened flywheels have been known to break so use good judgement.

[SteveH]

Timucin, That looks OK. Mine was machined on the back surface, just like the one in the pics. I didn't have the face surface machined, but that shouldn't cause any problems. The only issue I can see, would be if the machining on the front surface caused problems with balancing the crank.

[WabTheKing]

mate had his machined and then balanced simalar to how the do wheels where they add weights where required to avoid any undue stress on the crank

[timucin]

believe it or not but i drove 300 km today to find a shop to machine flywheel.normal machines cant d0 that ,it needs cnc machine; most of the cnc owners have jobs to do and their machines have other jobs on them.
finally found a place and left; will receive monday
will post pics

[Mark Halligan]

Timucin,

I'm using the 3B flywheel too and I have just been looking at the flywheel BOLT part numbers and they are different for the ADU and the 3B.
So if I am right you will need to use different bolts, presumably because of the different flywheel thicknesses and therefore bolt lengths???

The numbers I have found are:

ADU N906 604 01

3B N902 061 03

I use the online russian ETKA that is not always current, can anyone tell me if I am right about these as I need to order these a bit sharpish.

Cheers,

Mark.

[Doug_RS2]

Are these the 8 bolts that hold the flywheel to the crank?

I get

3B
N902 061 03
M10x1x19.5

ADU
N907 059 01
M10x1x43

Best to check with grandad, the guru or the daddy

[Mark Halligan]

Cheers Doug,

The P# for the ADU bolts is different but that doesnt surprise me as I know that the Russian site is a bit behind. The measurements are the same though, I think I will order up the 3b bolts.

Thanks,

Mark.

[timucin]

ok thnx for help wil check this

[s2avant]

Douglas,

You are quite correct. A++. Go to the top of the class.

3B
N902 061 03
M10x1x19.5

ADU (and ABY)
N907 059 01
M10x1x43

Ben

[timucin]

ordered!

[audiman]

Just a thought. How about grooving the flywheel like a brake disc to make it 'grip' harder?? Anyone BTDT?

[SteveH]

Just a thought. How about grooving the flywheel like a brake disc to make it 'grip' harder?? Anyone BTDT?

I don't think it would grip harder, but it may help to remove glazing if you're heavy on the clutch Like we know you are