Spinning or starter trying to engage after a run

[Irish in Oz]

After the bolt comes loose the rotor and shaft lock intermittently so the the engine starts OK, when it gets to the stage of slipping frequently the rotor and crank taper can become scoured and you never get full grip even when fully torqued, its like a morse taper on a drill.

[grog]

If the taper is worn, would you try Loctite 660 instead  of a new crank?

[Irish in Oz]

If the taper is worn, would you try Loctite 660 instead  of a new crank?

It could be worth a try Grog but both tapers would have to be cleared of any high spots.

[grog]

Irish, emery or linishing tape.Be appropriate you think.

[Irish in Oz]

I have just remembered about a process I got done on a crankshaft out of a two stroke outboard, I had a problem with crankshaft seal and couldn't get a speedi sleeve in that size. So I got it metal sprayed and it worked. Just google Metal Spraying.

[Eric GSX1400K3]

Definitely worth a shot, they will oversize it using metal spray, then remachine it down to spec. If you go down this route, rebalancing the crank and relinishing the journals would be an idea.

[PhilD]

Thanks for all of your input guys.
Thankfully we didn't have to go down any of the above routes.  I received the new rotor on Friday and everything was double checked including threads.  The new rotor and starter clutch were fitted and everything tightened up as it was meant too.
It turns out the old rotor was badly worn.  We can only assume when the original bolt backed off the rotor was moving and this is what has caused all the issues.

Anyway, it might me, but the bike sounds much better starting.

Again, thanks for all of your input and stay safe out there.

PhilD

[Mick_J]

Glad you got it sorted Phil, now don't waste the good weather, get out and burn some petrol.