06 yz450 transmission locking??????

Sometimes when I stall bike or go to start if in gear the bike will not let me kick. It's just locked solid. If I rock the bike with clutch in she will free up. I never had this happen with either of my 250f"s. Whats up. Also the tranny sometimes "thunks"when I shift up into second from a standstill. Is this a clutch thing or whats going on????

I know my 03 has had the kickstarter lock up after a stall, never lead to anything major wrong with the bike and I have been riding it for almost 4 years now. If the bike pulls when you put it into 2nd from neutral it could be clutch, I know mine makes a slight clunking sound when shifting into either 1st or 2nd at a standstill.

Clunking going into gear is normal. In neutral, the mainshaft spins while the countershaft is stationary. When you pull in the clutch to shift to 1st or 2nd, the mainshaft will still be spinning when the shift is made, as there is enough drag on a properly releasing clutch to cause that. Engaging the gear brings the mainshaft to a sudden halt, thus the clunk. As long as you can shift to neutral at a standstill with the engine running, the clutch is releasing as freely as you can expect it to.

The "locked" kick starter is more likely to be an engine that stalled as it came up against its compression stroke. When this happens, the auto decompression mechanism will be in its running, or non-effective, retracted mode, and if the engine stops with the decomp pin against the valve lifter, the flyweight spring is no where near strong enough to lift the valve by itself. Putting the bike in gear and bumping it backward cures this by rolling the cam back far enough for the pin to clear the lifter and extend.

O.K

thanks alot guys!!

The first time it happened to me, I was like &%$#@!. Like grayracer said, I rolled it backwards and all was good. I would say it happens to me once per tank of gas. Today, I got my sponsored Rekluse clutch kit and will install it tomorrow. Anyone have any install tips? I have high expectations for the stalling/locked kickstart issues w/ this bike. The rest of the bike is soooooo good. :thumbsup:

Edited for spelling, sorry to 'Grayracer'. :thumbsup:

Clunking going into gear is normal. In neutral, the mainshaft spins while the countershaft is stationary. When you pull in the clutch to shift to 1st or 2nd, the mainshaft will still be spinning when the shift is made, as there is enough drag on a properly releasing clutch to cause that. Engaging the gear brings the mainshaft to a sudden halt, thus the clunk. As long as you can shift to neutral at a standstill with the engine running, the clutch is releasing as freely as you can expect it to.

The "locked" kick starter is more likely to be an engine that stalled as it came up against its compression stroke. When this happens, the auto decompression mechanism will be in its running, or non-effective, retracted mode, and if the engine stops with the decomp pin against the valve lifter, the flyweight spring is no where near strong enough to lift the valve by itself. Putting the bike in gear and bumping it backward cures this by rolling the cam back far enough for the pin to clear the lifter and extend.

Good God man, how in the hell do you know all of this. You are like a friggen walking talking owners manual/encyclopedia/dictionary. Very very impressive. I too had this happen, rocked the bike, and started. Never would I have thought about the whole process described above. :thumbsup:
The first time it happened to me, I was like &%$#@!. Like gayracer said, I rolled it backwards and all was good. I would say it happens to me once per tank of gas. Today, I got my sponsored Rekluse clutch kit and will install it tomorrow. Anyone have any install tips? I have high expectations for the stalling/locked kickstart issues w/ this bike. The rest of the bike is soooooo good. :thumbsup:

You might want to edit this!

What I meant to say was that I have high expectations for the Rekluse clutch to eliminate the stalling/locking problem. At first I didn't get why you thought I should edit my post, then I read it out loud to myself and the point I was trying to make was not clear. Thanks for the heads up. :thumbsup:

What I meant to say was that I have high expectations for the Rekluse clutch to eliminate the stalling/locking problem. At first I didn't get why you thought I should edit my post, then I read it out loud to myself and the point I was trying to make was not clear. Thanks for the heads up. :thumbsup:

No...lol...You called grayracer "gayracer".

:thumbsup: That was a very innocent mistake. I'll go back and fix it. Sorry Grayracer.

For what its worth, im an expert at killing my bike right at that point in the compression stoke...do it all the time. You are not alone.

I'm certainly no expert, but isn't the compression stroke the only stroke on which your can really kill the engine? I'm just thinking through it logically and it can't kill on the power stroke, there's no pressure on the exhause stroke, nor on the intake....right?

I guess that depends on how good you are at killing it. If you're good enough you can stop it in it tracks no matter where it is in the cycle. Just lock up the rear brake with the clutch out going into a corner. Trust me im an expert LOL.

Gayracer, lmao, good one, a funny typo forsure..... Again Great info here guys, thanks.

I think I ran into this locked kickstarter issue this past weekend on my '03 WR450 with Rekluse (amongst other issues).

Let me run through the scenario for a sanity check.

I had been riding in the dunes all weekend on one air filter. The air filter became so clogged that the bike was stalling at almost every stop and then I was having trouble starting it. I ran the battery dead and began to use the kickstarter. Then every once in a while the bike would be impossible to kick over, like the autodecompress was not engaging. I couldn't put the bike in gear and rock the bike back and forth to engage/disengage the autodecompress system because of the autoclutch. Finally, I couldn't kick past the compression stroke and had to retrieve my bike with a truck.

So, fast forward to tonight and I'm checking my autodecompress system. First off, after removing the cam cover, I find that the pin is against the valve lifter. The action of the autodecompress is not smooth. After I retract the pin, it stays in that position for a second and then returns. I see some wear on the end of the pin also. Could the pin be worn to the point that it has mushroomed the head and is now interfering with the action of the autodecompress?

Also, can the autodecompress system be replaced or do you have to buy a new exhaust cam? I hope this isn't the case because the manual says that the cams and timing chain should be replaced as a unit.

Thanks for any help.

The AD system is not serviced separate from the camshaft. Try cleaning the mechanism at all points as thoroughly as possible before you decide to replace the cam. You don't technically have to replace the cam chain at the same time, but the chain should be replaced at least every two years, if not more often, anyway. It's easy, and it's cheap.

It's easy, and it's cheap.

You haven't heard my story about the one and only time I replaced my cam chain. :confused:

Thanks for the reply. :lol:

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