Crank shaft swap. injected for Carby
 

Hi Folks

I am having to go deep into my engine as it’s seized somewhere low down by the crank.

It’s a 2003 injected Supertwin. I believe the Carby Crank is stronger so while I am there would like to fit a Carby Crank.

Is it a straight swap or is there shimming or milling required.

Thanks

Monki

Re: Crank shaft swap. injected for Carby
 

I have looked into this myself and from what I could discover yes it should fit straight in as they are essentially the same item. However you will need to ensure that the bearing shells are the correct size and that the crank trust washer is the correct size also. This should be in the manual. Apart from that from memory its just the early injection cranks that were known for failing on the generator side.

However, thats an awful lot of work. Would it not just be easier to swap the engine to a carbed lump and just change the top end?

And if you do decide to do that I have a spare standard carb engine here for sale...

Re: Crank shaft swap. injected for Carby
 

It seems like a lot of work indeed. I have a spare carbed engine as well but reckon swapping the top end would be another big task.

Getting the bearing shells right would be my biggest challenge

A later injection crank would give me the same trouble/problem to solve?

Re: Crank shaft swap. injected for Carby
 

Later injection crank would be good, but you will still have the same bearing and thrust measure and install as you would with the curvy crank swap.

Swapping the top end and the associated bit is a big job but compared to splitting the cases and replacing the crank I'd prefer just to do the top end. Thats experience talking.

The easiest option would be just to replace the engine with another injection engine then.

However why are you sure that the engine is locked and the crank is the issue?

Re: Crank shaft swap. injected for Carby
 

Cheers lad.

Engine is solid. Thought/hoped it would have been the piston or bore but been working our way through it.

Heads are now off and the big end bearings are good so can only really be the main bearings.

Can only try and get the crank out and see and if I am in this far I would be as well to upgrade the crankshaft.

Re: Crank shaft swap. injected for Carby
 

What later years of Crank are more reliable?

Re: Crank shaft swap. injected for Carby
 

Not sure the years unfortunately. I just remember reading that the first injection engines occasionally suffered on the generator side. Might be worth checking the part numbers out across the years, that should show where changes were made.

Re: Crank shaft swap. injected for Carby
 

Will do Squirrel