Modern Vespa

I purchased SIP p/n 50004600 (Rally 200 femsa vespatronic kit). After installation the woodruff key gave way and completely knackered the crank and flywheel. The rest of the system is fine and I've got a new crank on the shelf. I reached out to my parts supplier and SIP directly looking for just the flywheel for this kit and it turns out it isn't offered my itself. It was suggested that I look at Ebay Italy, but that isn't proving to be fruitful. Does anyone have any ideas or leads?

EEK. That's a bitter pill. Sorry... no help but hope you find a solution. If you don't run down just a vespatronic flywheel and have to buy another complete kit, I think Pinasco makes a femsa compatible EI that will save you maybe 75.00 bucks?

Good luck

The only other electronic ignition option Ive found for the Femsa cranks is the Pinasco flytech. I don't think that would work for you as the pickup is different than the Vespatronics and I don't think they sell just the flywheel.

If you haven't already rebuilt things, I'd say swap the femsa crank for a p200 crank. Just need a different flyside bearing and seal. It opens you up to a lot more aftermarket ignitions.

I love my Femsa Rallys and the quirks that come with them, but when the Flytech craps out on mine, I'll swap for Vape.

In what way is the flywheel messed up? just the taper and keyway?

If so you may be able to clean it up and lap it to fit.

note: I'm running the vespatronic on my Rally and had to do a few modifications to the stator to get things to fit, but I think that was unique to the one i got.

The taper and keyway are completely shot, beyond repair.

The woodruff key is just a guide to keep everything lined up. Ie, soft and almost sort of sacrificial. If you have a good taper, you don't really need a key to hold things together. Can we see pictures of the shaft taper and the inside of the flywheel? Maybe its not that bad?

I'd say the little guy is pretty "fornicated"

I only have 1 thing to say...

Well actually, others have already said it...
What Have You JB Welded?

this was inspirational

See, nowhere near knackered!

There's plenty more gems of knowledge where that came from!

I bet you didn't torque down the flywheel nut tight enough before you tried it out? Ask me how I know, and more than once . As said, that small key is NOT to carry the load, the tight precise taper is designed to do that. Emphasis on tight. Making things worse is that it's an oscillating rotational load, your flywheel is 'pushing' for half of the stroke, and 'pulling' the other half and you can see that when the flywheel slipped, it hammered that poor key from both sides. Unless there's more damage we can't see, I'd have to agree. Looks like you likely still have 95+% of your taper surface in decent shape, I was afraid it would be all galled.

A half hour w/ a Dremel in there to remove the high spots, then onto a crankshaft to be lapped in. First coarse compound, then fine. Then small Swiss pattern files to clean up the keyway and a brand new snug key, then check to see if it catches the keyway. If it does, you're in business w/ your new crank.

So let's see your old crank.