Was riding into work today. 45 mile ride in beautiful weather, thinking about wether I would install my fork springs and seals myself or farm out, awed at how well the bike could pull up the long hill I was on (4 lane long steep climb over hill); life was good. Was holding 70 indicated then lost some power. Felt almost like a fuel cut but I just fueled up 30 miles ago. Was still pulling enough to get up the hill. Felt another power cut at the top of the hill. Was still running till I got near the bottom and cut out. Still spinning for a half second till I pulled the clutch in.
Coasted off the thruway to a grassy area. Noted some oil had sprayed from the front of the engine from I'm thinking the valve cover gasket (what?) But not a huge amount. Definitely enough had gone that I can't see the oil level in the crankcase any longer. Tried to start again... locked up engine...

Can't really tell what is wrong at this point. There was the copper speckled oil, but no chunks or anything. It felt almost as if the rings went (331 kit) which wouldn't be the end of the world as I could just have bill spec me out a new linning ala 351 (mo' Powa!). But still sucks none the less.

Was pushing to a Dinner a mile down the road. Passed by a guy fueling up a nice red viper who seemed plenty interested in what I was pushing. Was amazed that it was only 250 to begin with, very excited to hear it was now 331... though we both noted that now I was indeed pushing it.

 

What does the oil level look like?

 

Can't see it in the site glass. It had oil though, just checked a couple days ago.

 

Still waiting to be picked up. There are no further signs of oil leaking anywhere. Hit the starter and I can see the clutch budge just a hair but nothing turns other than that (good battery) put it in 6th and tried to get it to move, no luck. Going to be interesting trying to get into this engine.

 

How many miles on the 331 kit?
Brand?
I wanna do a big bore, but reliability outweighs my craving for power.

 

Take spark plug out and try turning the rear wheel

 

Doing a big bore usually doesn't affect reliability unless the compression is stepped up significantly or the engine at the edge of performance limits, like some sport bike engines may be. The KLX bottom end is essentially the same as the 300, and it was under stressed and would easily take the 331 or 351 without any inherent weakness.

To the OP, I hope any damage isn't too drastic.

 

Tried spark plug first thing when I got home. Bike has 3800 miles on it total, original owner installed it.

I really think its only the piston/rings that kicked it. Just a reason to have bill take care of it. Hoping I wont have much trouble getting it apart.

 

- At least the connecting rod didn't short out the spark plug..

Good luck in getting it running again asap

 

Sorry for your luck, on the bright side now you have an excuse to bolt on more cc's :-)
Keep us posted, really curious to know what the failure was.