Thanks for all the help and advice i have so much to learn.

Is there a way to tell the difference between a 350 ignition flywheel and a 250 ignition flywheel apart from weight ?

numbers or marking or do they look the same when fitted to the engine

Thanks again

BR

Edited July 23, 201313 yr by bultacorock

Some external rotor ignition flywheels on Bultacos are cast aluminium and some are cast in something that seems to have a much higher SG (zinc maybe). There are also different shapes. Yes there are markings but I don't know how to interpret them. I have quite a collection of Bultaco ignition flywheels and can do some photos of various flywheels and their ID numbers if it would help.

It would help if you could say which era you are interested in

Generally the 350 Sherpa flywheel looks like this. It has a squarer edge to its face than the 250. and is a lot deeper front to back

http://www.ebay.co.uk/itm/Bultaco-350-Magneto-flywheel-/181180646350?pt=UK_Motorcycle_Parts&hash=item2a2f3543ce

The 250 generally looks like this, it has a more rounded edge to its face than the 350

http://www.ebay.co.uk/itm/BULTACO-SHERPA-T250-1972-IGNITION-ALTERNATOR-GENERATOR-STATOR-FLYWHEEL-/400528679177?pt=UK_Motorcycle_Parts&hash=item5d415ea109

There are slight variances but generally, that's how they look. The 350 is thicker front to back than the 250.

This is for the FEMSA ignition, the Motoplat from the later bikes is different again.

Thank for the feed back Feetupfun and Woody.

Sorry i should have said i have a 199A with FEMSA ignition on my bike, thanks for the tips on how to tell the 350 and 250 ignition flywheels apart.

Just to get a better understanding what to look for when ebay shopping.

BR

hi joe i thought id emailed you with the same answer?

Hi Bondy,

Found your email thanks for all the info your 198A looks really good way a head of me, mine is still in bits. The box of new bits is getting bigger .....

One moment please.

There where both models/brands installed Femsa and Motoplat and to add a little confusion too, both where different in weight. I think it depended to which country

the bike was delivered.

Just now on vacancy and with limited access I have photos of both rotor brands even for both models, (250 and 350cc). The Motoplat ignition are some 100 gramm heavier. when I remember right.

Hi Pschrauber hows things hope your having a good summer its been really hot here in Waills and im a 1600m

I have a 199A with FEMSA ignition on my bike the flywheel has a squarer edge to its face i have attached a photo after looking at the photos woody sent me links

to i think it may be the one that should be on the bike ? fitted a new standard gear box sprocket cleaned it all up and put it back together. got the bike from a local

Yamaha dealer / MOT shop, it was one of the owners bikes. Im happy with it.

All the best

BR

Sorry i forgot to ask do they balance the flywheels so they are the same weight on both sides of the crank ignition and clutch side

thanks for all you feed back

Edited July 27, 201313 yr by bultacorock

Yes, that's a standard 350 flywheel

The flywheel itself may be balanced, I don't know, but they aren't balanced up to the counterweight on the clutch side as they vary in weight, shape and size for different models whereas the ignition flywheels didn't.

Yes the ignition setup looks very contemporary.

Next time you get in the situation for taking off the rotor you can look up if there are some holes (Sacklochbohrungen) just on one side, may in different diameter and only a couple of mm in depth. If so the rotor is fine balanced.

I have not seen any marks of fine balancing on the rotor of my bike so the rotor was not fine balanced at least for my bike.

If you want to get the rotor fine balanced let it be done if you not have the machinery to do so. I personal would wait until the next crank rebuild. Then the complete unit crank, rotor and flywheel can be balanced in one step. This would not increase the cost of the labor only a tiny little bit and the engine will run smoother too.