450 exc disaster

jacked450 · 06-11-2011, 05:30 AM

So i went for a ride this morning with a few friends. we were a few hours in and hit a fairly technical mud hole. needless to say i stalled. I then was un able to start my bike through the electric start and the kick was frozen stiff. Im worried it had seized but both oil levels and coolant are full and spot on. The bike is not having problems changing up and down gears, i say this as i have read a few reports about gear seizes. The bike rolls fine in neutral, cant think of anything else,,,, Please Help. Any tips and feedback would be much appreciated.

bajadog · 06-11-2011, 08:58 AM

You don't mention the year of the bike.

jacked450 · 06-11-2011, 05:40 PM

sorry it is a 2002 model.

bajadog · 06-12-2011, 02:36 PM

Ok,

Unless your bike is not a US model. then the 450 EXC started in 2003.
If your bike is a 2002 450 for sure, then it's not a US bike, and there
are some differences.

That being said, I would drain the oil into a contain that is fairly wide.

Sift around for metal bits, especially BEARING cage material.

Next step is to pull the clutch cover.

First what does the oil look like?

WoodsRiderParts · 06-13-2011, 08:16 AM

Time to start taking things apart. For some reasons mudholes seem to have supernatural powers, and they can really make some strange things happen to dirt bikes!

jacked450 · 06-21-2011, 03:01 AM

dropped the oil, no major peices of metal but the engine was sparkling a little haha. Engine oil looked really clean apart from the obvious presence of really fine metal sparkling in there. Pulled the engine now and will be checking out the piston tonight. any other tips or tricks.. also pulled the engine cover, all engine components look like there in great condition, no wear on any of the teeth or anything. it hadnt been ridden in a while so im thinking that there may have been some rust on the piston and its frozen.

bajadog · 06-22-2011, 11:51 AM

I did read some post about a cam lock nut issue with the 2000-2002 RFS engines. I guess you are doing the right thing as woodsriderparts mentioned.

Hopefully it's not your lower end (crank bearings).

Keep us posted on what you find, and good luck.

jacked450 · 06-22-2011, 07:25 PM

So i pulled it all apart. The timing chain had snapped and bunched on the lower crank. also one of the bolts securing the upper crank had come loose and had been getting a pummelling by the chain. Due to the nature of the seizure i was thinking this is actually quite ok. a mate thinks that i may have bent the connecting rod to the piston and bent and warped the crankshaft. i just cant see this happening do the the slow nature of the seizure. Thoughts?