Damaged piston (VFR400)

Originally Posted by Alpinestarhero

Does it sound like the engine is turning over at all?

Suspect sprag?

Did you try to bump it?

Yeah I bump started it. Was that a mistake?

[yorkie_chris]

The fact that as per your OP it started fine and rode home (did it feel OK?) suggests there's bugger all wrong mechanically.

Even after the bump start it rode fine.

I'm finding it very hard to believe that anything valve or piston would prevent it from starting, especially when you have 2 seperate heads and didn't hear anything go bang.
Have you checked all the basics, fuel air and sparks etc?

I've checked sparks and fuel. I tried starting it on the reserve too just to be sure.
And yes, I did check the killswitch

Now I'm leaning towards a starter fault as well

Originally Posted by EssexDave

Yeah I bump started it. Was that a mistake?

No, not at all tbh

Originally Posted by EssexDave

Even after the bump start it rode fine.

This is interesting. If the starter spins like mental, does it sound like there is any load on it? If you go and try to turn it over does the actual engine turn over? If not then sprag clutch could have gone... Im not sure if this happens on these bikes.

Erm, well I don't have the bike at the minute as the shop does. But I don't think it sounded like there was any load on it. But I can't remember, I've be around quite a few different bikes past 2 weeks with different problems. Bad memory.

Did he put oil down the spark plug hole and do a second compression test?