diagnose engine problem?

[Shockman54]

Hey guys, i appreciate any help you can give me, heres my story.

I was driving on the interstate going about 65-70 when there was a rattling sound and the bike started losing power. i killed the engine and coasted off the freeway. after i parked the bike i inspected the engine and couldnt see anything on the outside. so i decided to start it up again and the rattling sound was louder and the bike had trouble staying on. i was able to isolate the sound to just behind the shift pedal on the left side. so my question is, does anyone know what the problem could be, and how i could fix it? or do i cut my losses and try to find a new engine? any feedback is much appreciated, i would love to get my bike running again for the summer.

[TomB]

Just behind the gear peal is the final drive middle gearbox, you say you started again and it was worse, if you started it not in gear at the side of the road I wouldn't expect the noise to come form there, are you sure its not coming from the left hand crank cover, the ignition pick-ups are in there and can come loose and make noise, this would happen at tickover out of gear and would make the engine struggle to run. Its easy to check, take off the cover, theres no oil in there.

Or do you mean just inside from the gear pedal area?? again easy to check but will get oily. If its the selector mechanism broken it could be allowing gears to try engaging when in neutral.

[CatatonicBug]

If it was me, I'd just take that cover off and see if anything falls out. Of course, you'll want to drain the oil first.

[BA80]

i decided to start it up again and the rattling sound was louder and the bike had trouble staying on.

That right there sounds like the centrifugal advance shaft to me. Possibly something came loose or broke in there.

[motoman]

+1.......easy place to start and easy fix!.........eliminate the simple first.