300ex toook a random dump!!!!

[wheelie king]

On a trail ride tonight on the 300ex......all is going well, and she starts ticking really hard........I can smell what is like oil burning.......and in less than 30 seconds, I lose compression. It all goes to sh*t. Motor will not crank...turns over, but that is all. I got nothing.

I know something is cooked, and I need a top end. Why so sudden????? Anyone ever experience this or have any suggestions???????

And to make it all worse.....I had to be towed home by a Kawisaki !!!!!!!!

Your thoughts?????

[MichiganRedneck]

it sounds like you need a new top end. what year is it? has it been ridden hard? i would start by pulling the motor out and tearing into the topend. its a very simple motor to take out of the frame. replace all gaskets and put in new piston and rings and you should be good to go.

[wheelie king]

It is an 2001 and does not have many hours on it. Kinda suprising. It has NOT had a hard life. Sure ticks me off!

[Lomax]

I had one strip the lower timing (crank) gear out. Lost compression after that. When you start to pull the topend, take just the camcover off and then put a wrench (or socket and rachet) on the flywheel and gentley turn the engine over and see if the cam is trying to move. If that gear stripped then the cam will try to turn but then "fall back" to wherever its currently setting.

[Modded660R2fast]

If you dont have compression it sounds like your top end or your Piston rings. Do what the other guys said and tear down your engine starting with the head but dont take it out of your chassis. It is easier to just leave it in and work on it there.

[Wickedfinger]

Sounds like you dropped a valve .... tear that thing apart and let us know.

[wheelie king]

Have had no time yet, but I will let you all know asap. I am still getting over the fact that it actually happened. Pisses me off.

[jason85atc250r]

did you change the oil not to long before it died?

if you put the oil filter in backwards the oil will not flow threw the filter and no oil gets to the cam and rockers. the 250x and 300ex will do that. 350x's will to.

[wheelie king]

YOu know what????? I DID change the oil not too long before this happened. Damn!!!!! I am going to pull the filter and look.

[okieRrider]

That happens a lot, filter in backwards and pretty much does what you are talking about... 400ex's do it also, not on mine but I have seen plenty of them to remeber it.. If that happened the head is probably trashed in the cam journals also...Chris

[wheelie king]

The damn OIL FILTER was in BACKWARDS!!!! AAAAArrrrggghhhhh!!!!

I feel like a moron. I am no master mechanic, but have turned a wrench or two....but have NEVER done anything so stupid. Guess a 500 dollar mistake would teach me to pay attention next time. Thanks for you guys' input. Now go ahead and laugh.

[Chrisbroeders]

sounds like she ran low on oil.. i had the same problem on my 250x.. it started pingin and she seized up on me.. checked the filter and sure as shiet she was in wrong.. because of the person i bought it from

[Charles Ford]

Hey my brother was out riding and his started to slow down so he started to give it more gas then his bike just stops. he try's to kick it and it would'nt kick over. he sets there for a while and then retrys it start's up so he figure's he better go back to the truck.it does this 3 more times and then the last time it won't turn over. he bring's it over to me and say's he thinks his rear bearing's locked up. I say how could you roll it if the bearings are locked up. well he had my buddy do a oil change on it and he did not tighten the drain plug. the top end was shot and he sold the bike for chump change instead of fixing it. so always check your drain plug. 2 seconds are worth it. I need 400ex part's (frame,rear carrier,etc) if you know anyone that dose let me know. I just put a custom 500x atv,xr100,tree spurs,sears snow plow,250 interceptor complete motor on e-bay.
you could put a 350x in your 250x it's not that hard.
Thanks Chas