i`ve seen quite a few std factory "one piece" flywheels crack right through the guts/centre.

seen em open up like the grand canyon, I`m not "That" much of a fan of them after seeing that.

these are my 2 piece lightened flywheels.--->

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

mines two piece, 6 bolts in the centre and six around it

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

Look good Matt , for curiosity's sake , how much weight is taken off in total and how much on the outer edge where it's relevant (well , you know what I mean , how much good weight is removed as well as just lightening the flywheel in total ?) and how much are we looking at for them ?

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There are advantages to both types, IMO.
1 piece- the hub is cast iron, less likely to friction weld to the steel crank tail on high power motors.
1 piece- allegedly (slightly) lighter than the 2 piece.
2 piece- the hub is steel, so less likely to crack as TheMiniMan says the 1 piece one does.
2 piece- if you ever do bugger up the hub the whole flywheel is not trash, you can fit another hub.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Pretty sure I've got a 1 peice somewhere.. I'll have a look, if you still need it..

By 2 piece are we talking about the original 850 flywheel that was 2 piece or are we talking the newer light weight ones?

If the original 850, I therefore have one of each so which to use? I'll be getting the flywheel faced off after Christmas and balanced with crank and harmonic balancer (if it ever comes back from Ross Tuffbond )
so I may as well use the better of the two.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Most racers have a scatter shield...someone here should be able to rustle up a picture. If it worries you that much, fit one for your own piece of mind.

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"Show me the Mini!"

There are 3 different 2 piece std flywheels.
Original 850 had a 1-3/8" bore and 6 coil springs.
997-998 (and later 850) had a 1-1/2" bore and 6 coil springs.
Diaphragm 2 piece ones came out 1965 approx, they had 1.5" bore and no coil spring holes.

One piece flywheel came out in the 70s.

The diaphragm spring can be used (sort-of) on an early coil spring flywheel but the contact point on the flywheel is not quite the right shape.
I'd get a diaphragm spring flywheel if you are running a diaphragm clutch.
In your case I'd use the 1 piece one you have.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I used to run a light steel one piece flywheel and would have a hell of a time getting it off the crank. Caused me so much grief, it now sits in the corner of the shed. Similar experience to Matt68 with runout etc.
I had a 2 piece steel flywheel made, uses stock mini centre, steel outer, similar design to one piece steel, just with removable centre. This is for race use.

For road use, as DRMINI says, .200" faced off with suitable spacers & rebalanced is all you need. I always lighten the back plate too, but the proper one. Steve

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Steve

apart from having, or so i've been told " the heaviest of all flywheels" what does a a+ 1275 have? one or 2 piece

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real men race downhill - keiichi tsuchiya

Can be like those shown, but also could be a 'Verto' Clutch, this is probably what the reference to 'heaviest ever' was!

I believe the trend in the UK is to chuck em and fit more traditional types.

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Sir Alec! we are not worthy!

The heaviest one we ever got here in Oz was the Morris 1100S, it had bloody big bits added front and rear at the outer edge of the casting.
WTF were they thinking...
These turn off nicely though.
I have 2 of `em to lighten, I'll weigh the buggers before and after.

BTW the 1100S also got the nice `22G270' Cooper S SG iron backplate. THE one to lighten.....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

This is a Verto flywheel.
Lightened.

For sale.

how much?

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real men race downhill - keiichi tsuchiya

Still looks huge