chain slap

I know I'm new around here and I did try to find other threads about it before posting.....

But does everyone else have to keep their drive chain at the minimum (1.6in) measurement (or a hair under that)? The acceptable range is 1.6in ~ 2.0in according to the service manual. I mine gets anywhere above 1.6in, I get slap in first and second gear if I'm not in the trottle good.

One other quick one.....Anyone know if the service manual for the '00 is the same manual you get with the '01? I have an '01 YZ426F and ordered a replacement manual. It looks like it might be the '00 manual.


jason s.

I think if you check some of the posts you will see that most of us actually run the chain with a little more slack than is called for in the manual. I believe the consensus is that a chain adjusted at the called for spec has been a contributing factor in premature hub failure on some bikes.

I just made this post today on the wr side.

Hearing the same noise in 1st and 2nd unless in the throttle good.

My 01 426 makes a lot of chain slap noise on the low side of mid-range but not bogged. Mostly in 1st and 2nd. Dont notice it much in third. I am going to pull the valve cover off and check the chain and cams.

Every once and a while the kick starter has a funky click to it. Can't explain it. It almost feels like it breaks or skips. It doesn't do this during the kick stroke, but every once in a while when doin the routine to get to TDC.

Those are my current issues. Any Ideas??

Mike: I was referring to the drive chain - not the timing chain. I believe my noises are coming from the drive chain since it goes away if I tighten it a bit :).

Tom: Thanks for the input....I ride with the chain within spec (and get to hear the slap when putting around in 1st and 2nd), but noticed that if I have it on the tight side (1.6in) the slap goes away. I hear what your saying about the hub failures. What type of riding was being done when this occured? MXing? And just to clarify, you are saying that I should adjust the chain to beyond the loosest spec (above 2.0in play)?

-jason s.


I am wondering if that is what I am hearing. I can't really pin point the noise.

Mine does the same thing. I tighten mine to about 1.6 at the beginning of the day. In an hour or two the slapping chain noise starts to come back at low speeds in 1st-2nd gear. Im still using the stock chain and havent had any hub problems. I wonder if the guys' whos hubs exploded were using aftermarket chains? Since the stock chain streches so quickly, it may work as insurance to prevent the exploding hub/sprocket problem.


Are you guys hearing the same thing I am? Mine has a clicking kind of noise coming from the countershaft sprocket, kind of like the chain is skipping teeth, but everything is pretty much new. The chain is tracking straight. It does it in 1st, 2nd, and 3rd primarily. When putting around you can't tell, but when you get on the gas out of a turn the countershaft area is clicking.....

Doesn't sound like a cam chain situation to me, but any ideas would be greatly appreciated. :)

So pin it. I don't see the problem?

I also have the chain slap noise, and it seem to come right from theswingarm pivot area, what i do to measure chain slack is to put three fingers at the end of the chain slider of the swing arm, and the chain should stretch far enough to let you get your fingers in it.......nasty

When I first got my 426, I was adjusting the chain nearly every ride.

Since I stopped adjusting it, it has stopped stretching out so quickly.

Next time you disconnect the shock/spring move the swingarm through its travel and check the chain slack as you do, you may find that if the chain is set at a comfortable level of slack when it is just sitting there, it is very tight when it is 1/2 to 2/3 through the travel.

I also did go to a did gold chain.

Dave S

I dumped the factory POS chain and replaced it for a DID X-Ring which for the most part cleaned up the sound of my drive line..

Has anyone tried the Stainless Steel sprockets? Wondering if the do last as long as they say they do....... 4 - 5 times longer than regular ones. ?

Ontario - I recently sold a 1993, yes 1993 YZ250 with an RK chain and and a carbon steel sprocket (stainless was not the rage back then). I put these on after the OEM stuff wore out after the first 6 months. These were the only ones I put on the bike in all the years I had it. I did race the bike a few times, but don't anymore. I do a lot of riding, but not racing allows time for checking things over thoroughly.

Right now, I am still on my original 2000 426 chain and sprockets, but I plan to go with the stainless and an RK or DID.

It's well worth the price, even though I hate to think of adding even an ounce more weight to this beast.

just my $.02.


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