[cadunkle]

Today I rode the F11 out to the woods and romped around some trails. Rode for abotu 2.5 hours total. On my way home the engine just lost power and stalled when cruising at maybe 35-40 MPH. Thought maybe I was running out of gas, so pulled over and flipped reserve. Kicked it over, nothing, kicked again and it seized up. Solid, won't budge now even after cooling off.

I figure maybe the oil pump wasn't oiling like it should have been even though I adjusted it as the manual said to. With this and my past experiences with two strokes I'm starting to think they are all just unreliable junk.

Well anyhow, I guess I'll find out what the deal is when I take it apart.

 

[kawah1c]

Please let us know when you find out.

 

[kawracer]

Sounds like the big end rod bearings failed. I had a F7 that the engine tightened up, could kick a few times, then locked. The rod bearings rollers were melted.

 

[cadunkle]

This could get time consuming and expensive. I was hoping a top end rebuild would do it... Like maybe a ring cracked and got caught in a port. I hate pulling motorcycle transmissions apart. I've done plenty of toploaders and T-10s, but every motorcycle trans I touch is a major headache.

 

[cadunkle]

I think I found the problem... The engine seems to have ingested a nut with a 10m hex!

I pulled the head and found a bunch of crushed up aluminum in the cylinder. Pulled the exhuast and found a crapload more and the nut. No idea where the nut came from. Sure explains why the bike ran fine and no problems when I was beating on it on the trails, then randomly died out and seized when cruising along.

I'm disgusted. I imagine the whole bottom end is trashed, who knows how long that nut was banging around down there before making its way through the cylinder. Anyone have a spare F11 engine?

 

[cadunkle]

Uh-oh...

Well, there's yer problem right there!

Like I said, I was too disgusted to keep pulling it apart last night. Gonna go grab a six of Weyerbacher and pull it apart some more. I'm guessing the bottom end is trashed. I hate pulling bike transmissions apart.

 

[cadunkle]

Well the nut made it ito the engien jsut fine. Slight problem on exit though. Looks like it caught the bottom of the piston/skirt on the exhaust side. Skirt on exhaust side is gone, intake side fractured. Exploded into a bazillion pieces. Engine crapped out when skirt broke because it threw the exhaust timing way off. Then a second or so later when the pieces all rained down onto the crank... Well they wedged i there pretty good scarring the counterweights and jamming them tight to the case. The rod doesn't move very freely on the big end so I believe a bunch of crap is jammed in there too.

 

[jeepurz]

man that sucks! where the heck would a 10mm nut have room to get into it. did you drain crank oil? any bits in there.

 

[cadunkle]

There is no oil in the crankcase, an F11 is a two stroke. Since two strokes vibrate a lot maybe something worked loose but I still don't understand how it got into the air box. I took the air filter out and cleaned it when I got the bike, didn't look real close for any debris in there but didn't notice any junk at the bottom of the filter housing. So much carnage. There are little bits of piston everywhere inside the engine. Can probably salvage this engine but I'd rather find a good bottom end I don't have to pull apart.

 

[A2rider]

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