Good question .... the Fazer crank end is longer so there's actually more material there than 3HE, I did you a little drawing

A good little drawing, as I would expect from a man of your profession...

Just a little clarification though, is that the taper from the 4JH, or from the Fazer (5DM)?

Alex.

Sorry it's taken from the Fazer - I couldn't get the flywheel off the 4JH crank.
As far as I know the 3HE has the same timing as the 4JH so you can use the same electrics - maybe

Uh oh, brain working overtime...

If the 3HE taper will fit within the required taper for the 4JH/5DM, would there be enough gap to make up a 'spacer'? A bit of metal turned up to be a snug fit on the 3HE taper on the inside, with the outside being the correct taper for the 4JH? There could even be a slot for the woodruff key to keep everything in line.

There would not be much metal, but it might work....
If only I knew of someone with a lathe in their garage, hold on!! That would be me!

Alex.

Evilchicken0 wrote:Sorry it's taken from the Fazer - I couldn't get the flywheel off the 4JH crank.
As far as I know the 3HE has the same timing as the 4JH so you can use the same electrics - maybe

There are some diagrams over on FZRarchives that show the differences. While the timing my be the same, how the CDI is kept informed of the position of the crank is different.

Alex.

Edit:- Here's the thread with the trigger pics in post 4:-

http://www.fzrarchives.com/ipb/index.ph ... l=dadrider

Hmmm - might be an idea to have it welded and machined back then ???
The only other way would be to make a spacer but the chances are it would slip.

Even if there was a slot running the length of the spacer on the taper, with the OD being ever so slightly larger, so that the flywheel pushes the slot closed ensuring that the spacer grips the inner taper?

I know what I mean, just can't say it too well!

Alex.

Superglue you mean ... nah you'd heat the spacer and rely on an interferance fit, shirley ?
You'd need a deeper woodruff key though.

This was a good idea when I drew it but so good now - the turning moment of the stator may shear the end of the crank

I like the way you are thinking!

But, turning the end of the crank would be a right nightmare! It is definately not something I could do with my little hobby lathe and just think of the out of balance forces on the lathe when spinning the crank (without rods & pistons or a bottom end to hold it steady).

Alex.