Triumph Scrambler 2013 - Cam Chain Stuck And Stopping Engine Rotation

spinosaurus7 · Mar 12, 2024

I'm rebuilding the engine on my 2013 Triumph Scrambler. After joining the crankcases I mounted the engine to the frame before adding the top end to reduce the weight.

But now I'm running into an issue with the cam chain. It seems to be stopping the engine rotating. The left hand side seems to be engaging when I manually rotate the crank until I hit some kind of stop. The right hand side doesn't seem to move at all. The cam chain is also shorter than it should be. I've therefore reached the conclusion that some chain is stuck somewhere in the crankcase.

Does this seem likely, and if so is there anything I can do without removing the engine and splitting the cases again?

Samsgrandad · Mar 12, 2024

Looks as if the cam chain has come off the sprocket on the crank and is locked up in the crank cases, towards the front of the engine. You may be able to wiggle this free or if not just try lifting the barrels up enough to get into the opening and work the cam chain to try and free it. You may get away with just lifting the barrels up to the lowest piston rings, so you don't have to recompress the rings.
Been there myself and got the T shirt but with a Honda engine!!
Best of luck!!

RickM46 · Mar 23, 2024

Any news??

spinosaurus7 · Mar 27, 2024

@Samsgrandad was spot on! I borrowed a bore scope to have a better look and the chain was properly stuck under/to the side of the crank gear towards the front of the engine (see photo below, unfortunately I didn't get a better picture).

I pushed and wiggled and rotated for hours but that chain was going nowhere. I'm moving house, so have put the bike back together for the meantime and will have another stab when I've got my garage set up in the new place. If I can't get it free then I've resigned to the fact I've got a full teardown on my hands.

If anyone has any tips/tricks in the meantime then please let me know!