starter issues
 

bought 91 baja 240 with blown motor......

Pulled motor...ended up having to get new block and did entire rebuild....installed motor with same flywheel but having starte issues....a couple times it fired right up and a couple times it sounded like its chewing up my flywheel

Getting any water in one of the cylinders? What does the mating surface look like between your exhaust manifold and riser?

Sounds like you are getting some water in the cylinder and the starter is grinding on the flywheel when the piston is trying to compress it.