WR400 Engine lockup

A buddie of mine has a 2000 wr400 that was running fine on a Yz timing. After about a 80 mile poker run we stop to take a break and when he tried to start it the motor made horrible noise. He shut it down to see &%$#@! and tried it again and it was locked up. Upon checking on it later he had dropped one the keepers that hold the cam shaft in place when he changed timing.He fixed that with a new keeper. The wr ran great for the next poker run, but did the same thing again. He pulled the valve cover to see if it was the same thing but it was not. When he checked the timing he said that the intake side jumped time. He reset the timing and kicked it over a few times and the timing jumped again. Anyone out there that can offer some advice.

Non operational chain tensioner, stretched or worn chain.

If you can adjust the cam timing without removing the camshaft itself (or it's bearing cap), the chain is worn out. It might be as well to check the teeth on the crankshaft too as I've heard of them breaking off.

Good luck!!

If she locked up, there is a very good chance that a valve was damaged and or the piston. The vavles really dont like hitting the piston :crazy:

buddie tore it apart and found a kinked timing chain. The chain took out the front guide and messed up the crank gear. He's got parts on order to see fi a new chain and guide will do the trick. No valve damage. Thanks for the input

Any idea, how old was the chain or how much it had travelled approx?

Im into replacing mine after 28 months and about 3.750 miles.

Comparing it to the chain installed before the last one, it showed no stretch, Ill compare it to the new one, when I get it.

It is a known weak link for WRs and is said to replace it once a year.

Price for 400 chain is almost two times the price of 450 chain.

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