Author Topic: Flywheel on 350cc H3  (Read 1653 times)

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Offline douglas1947

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Flywheel on 350cc H3
« on: 15 Feb 2018 at 05:32 »
Iīm restoring an 350cc engine type ER (for a H3).
The flywheel hole in the center is made out of brass and badly worn; I think it is allready an old repair.
I have bought an other flywheel, nearly same dimensions, but a bigger hole (steel center, no slot for key) in the center, so the crankshaft tap do not fit.

Has anyone a idea?

The tap on the crankshaft is also worse, but I hope I can weld it up and renew the surface in my lathe.
I think the big ends are repairable with oversize rollers.

Michael

Offline eddie

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Re: Flywheel on 350cc H3
« Reply #1 on: 15 Feb 2018 at 07:38 »
Hi Michael,
                 Before attempting any welded repairs (which could weaken the end of the crankshaft), I would set the crankshaft up in the lathe and clean up the taper. Then do the same with the flywheel (to remove the brass from the previous repair). Then turn up a tapered sleeve, and lap it to the crankshaft and the bore of the flywheel (some trial and error will be needed to get the correct clearance for the clutch operation). When you are happy that everything is fitting together correctly, cut a slot in the sleeve for the flywheel key. When fitting the key, make sure it is not too full, as that will hold the flywheel off the taper.
  Good luck with the repairs,
                                         Regards,
                                                       Eddie.

Offline douglas1947

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Re: Flywheel on 350cc H3
« Reply #2 on: 15 Feb 2018 at 11:19 »
Hi Eddie,

thanks for the advise.
Of what kind is  the seperate center piece in the flywheel fitted?

The repaired H3 flywheel with the brass center has also 2 steel pins of 1/4" dia to fix it in the hole (see photo). I think thatīs not original and worse to the flywheel for the next repair.

The other flywheel I have bought looks very similar in dimensions, but has a bigger hole (with a steel bush, no key way in it). It should be from a 500cc/600cc model.
I think there is no reason to fit a key to that flywheel cone anyway?

I will have a problem, if it is necessary to fit the flywheel in a lathe, I have only a Myford 7.

There is also a person offering a flywheel (for a EW350?), but this flywheel looks different and has not the same center and fixing nut.
So there is no sence to buy it!

Michael


Offline douglas1947

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Re: Flywheel on 350cc H3
« Reply #3 on: 15 Feb 2018 at 15:14 »
Some photos!

Flywheels have both 235mm dia, the red one was to engine ER812,
the black a 500/600cc flywheel?

Offline douglas1947

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Re: Flywheel on 350cc H3
« Reply #4 on: 15 Feb 2018 at 15:16 »
Flywheel to engine ER 812

Offline douglas1947

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Re: Flywheel on 350cc H3
« Reply #5 on: 15 Feb 2018 at 15:18 »
Crankshaft driveside

Offline douglas1947

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Re: Flywheel on 350cc H3
« Reply #6 on: 15 Feb 2018 at 15:21 »
The ugly pins of cone bush