Crank gone bad!!!!

[Cr_125]

Hi.Was very happy today as I got new graphics and an icat all fitted to my bike and I went down to the beach to test out my new icat!! I started the bike and warmed it up for about 5 mins and then went riding up and down the beach, did about 4 laps of it then the bike make a noise and cut out!! I got off my bike and pushed the kick-start with my hand and it was stuck! First thing came im to my head was seized piston and I push it back and brought it home. I took off the exhaust and there was very very small bit of metal, so I took off the head and cylinder to realise that the plating was undamaged, not a scratch, but the crank was turning rough! It’s not the crank thing its the rod, the crank moves fine but the rod moves very rough.

Also the piston and rings have less than 2 hours on them.


The piston has some light mark and the top but looks fine. Can I just sand the top to get it smooth again or does it need to be replaced.

The crank rod has a bit of metal on the side its very small on the right hand side of the rod.

And it looks as if it is red-hot and the bottom of the rod.

Any ideas what the problem.If I was to guess I would of tought it would be the rod bearings are gone!
If anyone can tell me what it is and how big a job it is and what would be the cost of part to be replaced ? Any help would be great. Thanks

 

[TimberPig]

Yup, sounds like a rod bearing has gone south.

To fix it, the cases must be split and the entire bottom end of the engine has to be rebuilt. Here's a couple links that might give you an idea of what you are looking at having to do.

Bottom End Rebuild
Crank Rebuild
Crank Checking

Parts cost, is likely about $300 US. It partly depends upon how much you can do yourself as to the labour cost.