Scooterotica

I've never snapped one on the taper or known anyone that has but I know Innocenti upgraded them with the GP range etc. Ironically, I've known plenty of GP cranks fail, mainly the SIL ones with the dodgy big end bearing, as we all know.
I heard some where that Li cranks can still handle up to 20hp but that sounds high.

All depends on the weight of the flywheel that you run them with... or so Webbo used to say, stating that he even ran LI/SX type cranks in race motors, when they had naff-all flywheel weight.

I've seen plenty of failed LI/SX tapers when run on 200+cc motors but less on <200cc.

Adam

GT 186 a couple of years ago

I had a crank snap on a sx150 many years ago but I had slapped an imola kit on it

I wish I'd taken photos of the sheared ones that I've seen, especially the more recent 2 x Jet 200 examples as I'd warned these pals that it was a reasonably high % risk (having seen a number go before, incl. standard TV200 with correct brass/alloy 6-pole flywheel). Neither of these 2 pals thought it would happen to them but the fact that they both used them regularly and clocked up the miles made me think that they could suffer it, which most 3 x Sunday ride out riders might not do the miles to encounter.

If you actually plan on doing the miles then it is an obvious and easy known failure point to avoid.

Adam

The one in my post was a Jet 200 Adam.

Yep, it is more common on the 200+ cc motors as the taper has to handle more strain under engine breaking whilst the flywheel wants to keep spinning but the more substantial volume/compression fights against it. That said, when we've gone over this issue before we've had a few people pop up and say that it happened to 150 and even 125 machines too.

The Jet 200 normally suffers the worst as late examples had the very heavy Motoplat electronic flywheel, which is even heavier than the Indian electronic flywheel that yours was using. It should be noted that yours has suffered this with the lighter than Motoplat electronic so simply swapping to the Indian item did not lighten it enough. The 6V Ducati brass and alloy one that I mentioned seems like it would be lighter still, yet I know of 2 examples of these shearing tapers on standard TV200s.

If I was looking to run an LI/SX crank then I would at least look to change to a lightened Indian electronic, if I didn't want to change to a GP crank and flywheel. Ideally the AF light flywheel would be better still, however, I've witnessed 2 of these fail because of magnet covers coming loose and there are yet more examples of these failing if you do a web search on the subject.

Adam