WR400 - adjusted valves - kick over lockup

25 replies to this topic
  • tgodwin

Posted April 06, 2005 - 07:18 AM


I've been thinking about your problem and wondered if you are one full rotation off on timing between the crank and the cam shaft. Maybe try and take the timing chain off with the cams lined up correctly and rotate the crak one full rotation so the I lines up again. If you rotate twice you will be exactly where you were before.

I have torn mine apart to this point so I'm not sure if I'm lost in space or not, but there maybe be a slight angular difference from stroke 1 to stroke 2 that is causing the binding you are experiencing. I know with a multi-cylinder engine the crank has to be in exact alignment with the cam before you put the chain on, maybe the same principle applies on a single cylinder engine. Please keep us up to date, we'd like to hear how you resolve this.

  • R_Little

Posted April 06, 2005 - 11:09 AM


I don't think it matters when the "I" shows up.
The motor goes through one TDC with exhaust valves open and another one with all valves closed. I believe the ignition fires both times so I dont think it matters. If the "I" and the cam marks line up it should be okay which ever stroke it reaches first. Correct me if I'm wrong.

To be sure you're using the correct rotor mark you could stick a pencil in the spark plug hole and make sure the piston "is" at TDC when the "I" mark appears. The cam marks should line up then.

On the other hand if it still locks up with the cam chain or the cams out and the valves closed then it is not a valve timing issue. I could be normal engine compression though.

Why do I suspect that that decompressor is not holding that valve open and the compression is locking up the motor? I'd take the spark plug out and make sure there is no compression in the motor then see what happens.

  • ex_junkie

Posted April 07, 2005 - 05:46 PM


It does matter which stroke it's on. U have to be on the compression stroke. To check and see if your on the compression stroke put your thumb over the spark plug hole pluggin it off so the pressure builds. With it covered turn the engine over until u feel pressure. THis means that all valves are closed. Sounds like your on the exhaust stroke since u said the exhaust valves where open. Since u have been fooling with it and been hearing funny noises from trying to force it to turn u need to tear it back down and check the valves and piston before u do anything. Running or not running u could have bent a valve or chipped or cracked the piston.

Sorry for the news but this is what it sounds like.

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  • joecallan

Posted April 17, 2005 - 10:49 PM


:D Okay!

I found the dealio. :cry:

I took it for a spin today down the street - street legal.

It hauled butt and idled perfect at start, like brand new. :D

I messed around with it over and over, when the timing chain was disconnected. I cranked it over with the kick start again, holding the timing chain up just right. I found out that, it was balling the chain when it was locking up. So, I thought maybe one of the guides was messed up, but then I thought that couldn't be. The guides seem to fail safe. Then I messed with the tensioner and noticed, IT LOCKS at the end! I didn't know this when putting it in and was holding it as I put the 2 bolts in, to keep it from springing back (a huge bitch). I didn't know I had to release the spring back. But then again, I thought I saw the chain getting tight before :naughty:

By the way, it doesn't matter what rotation it's on when you line up the "I". Every revolution on the crank is the same.

Well, I didn't have to take the cyclinder back off!!! :D thank the moto gods.

It started easy, ran smooth, and had power. BUT, it makes a light ticking noise. IS that normal?? :naughty: I don't remember it. I checked the valve clearance a billion times over - it is good!

We'll it works great and I'm happy! :D
Tears of joy. :D

Thanks everybody:banana:

  • Slowmotion426

Posted April 17, 2005 - 10:58 PM


Well i'm glad you didn't take any advice from me...
Glad you got it running!... :naughty:

  • tgodwin

Posted April 18, 2005 - 03:42 PM


Thanks for the follow up. Glad to hear you are up and running.


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