12 year old cam chain

I've had my 2000 WR400F since 2003. I fiqure I have at least 12000 miles of trail riding on it. I consider my bike well maintained. I have the original cam chain still running the original valvetrain. I was warned by a fellow rider one day at the trailhead this fall that I need to replace the cam chain after every 25 hours of riding. I was shocked, I have never heard of this for a WR400F. I have heard that the '03,'04 YZs have had issues but not the WRs. I will be replacing the cam chain before the next ride but I was wondering what everyone else's opinion is about this? How often should I be replacing the chain? It is a very cheap cost to avert a very expensive problem! How often do you replace yours?

I've had my 2000 WR400F since 2003. I fiqure I have at least 12000 miles of trail riding on it. I consider my bike well maintained. I have the original cam chain still running the original valvetrain. I was warned by a fellow rider one day at the trailhead this fall that I need to replace the cam chain after every 25 hours of riding. I was shocked, I have never heard of this for a WR400F. I have heard that the '03,'04 YZs have had issues but not the WRs. I will be replacing the cam chain before the next ride but I was wondering what everyone else's opinion is about this? How often should I be replacing the chain? It is a very cheap cost to avert a very expensive problem! How often do you replace yours?

At 12,000 miles your piston, rings, wrist-pin, timingchain, chain tensioner, are all shot 6,000 miles ago.

Just because it didn't blow up doesn't mean it's not worn out.

You should do a leak down test on your head while your at it to see if the valves still seal.

I've had my 2000 WR400F since 2003. I fiqure I have at least 12000 miles of trail riding on it. I consider my bike well maintained. I have the original cam chain still running the original valvetrain. I was warned by a fellow rider one day at the trailhead this fall that I need to replace the cam chain after every 25 hours of riding. I was shocked, I have never heard of this for a WR400F. I have heard that the '03,'04 YZs have had issues but not the WRs. I will be replacing the cam chain before the next ride but I was wondering what everyone else's opinion is about this? How often should I be replacing the chain? It is a very cheap cost to avert a very expensive problem! How often do you replace yours?

I changed the timing chain on my 2000 around 7,000 Miles. it was pretty stretched out (more then a half inch longer). Definately check the valves while your at it. My piston looked great still, just had to re-ring it.

I changed the timing chain on my 2000 around 7,000 Miles. it was pretty stretched out (more then a half inch longer). Definately check the valves while your at it. My piston looked great still, just had to re-ring it.

At 8K miles on my wr450, my cam chain had no stretching. I replaced it anyway because I had already bought it.

I would definitely go longer than 25 hrs. If its truly been 12K miles, then I would change it out soon. Why take the chance knowing that it will last you another 10 years if lasts like the current one.

I have a 98' WR400 with thousands of trail miles on it and a few race miles as well. Original top and bottom end still there. I did change the cam chain a couple of years ago, just because it seemed like the right thing to do, however it and the sprokets looked fine. It was slightly longer than the new one but well within the ability of the chain tensioner to handle. Chains don't acutally "stretch", rather the individual pins and links wear slightly causing the length of the chain to increase slightly. It's good insurance and cheap to change the chain every so often, but these engines are very rubust unless used for constant racing. After all these years mine still has good compression and runs and starts great. I suppose it is probably a little down on power, but not so I can tell. I mostly ride (and live) in Baja now and I don't hesitate to take it anywhere.

I have a 98' WR400 with thousands of trail miles on it and a few race miles as well. Original top and bottom end still there. I did change the cam chain a couple of years ago, just because it seemed like the right thing to do, however it and the sprokets looked fine. It was slightly longer than the new one but well within the ability of the chain tensioner to handle. Chains don't acutally "stretch", rather the individual pins and links wear slightly causing the length of the chain to increase slightly. It's good insurance and cheap to change the chain every so often, but these engines are very rubust unless used for constant racing. After all these years mine still has good compression and runs and starts great. I suppose it is probably a little down on power, but not so I can tell. I mostly ride (and live) in Baja now and I don't hesitate to take it anywhere.

Um, yeah, they do. They stretch enough to no longer fit correctly on the sprocket (spacing between pins increases) and then it jumps teeth.

I don't understand why people are trying to stretch the life out of a 30.00 part? It's not worth the risk.

Um, yeah, they do.

Um, no they don't! The overall length of the chain does increase, but not due to "stretching", rather due to wear as I stated.

In my personal experience, these chains do not wear excessively fast and do not need to be changed too often. This, of course, assumes good routine maintenance (e.g. oil changes) and no abuse (e.g. bouncing off the rev limiter in every gear).

Of course, this is just one person's experience, although I do have 4 or 5 riding partners with WR's who also have the same experience.

Um, no they don't! The overall length of the chain does increase, but not due to "stretching", rather due to wear as I stated.

In my personal experience, these chains do not wear excessively fast and do not need to be changed too often. This, of course, assumes good routine maintenance (e.g. oil changes) and no abuse (e.g. bouncing off the rev limiter in every gear).

Of course, this is just one person's experience, although I do have 4 or 5 riding partners with WR's who also have the same experience.

Well, no, the side plates do not stretch, that's for sure. But the length of the chain gets longer because the bushings wear, and the space between them gets longer. Technically, that is not stretching. But the chain does get longer.

Well, no, the side plates do not stretch, that's for sure. But the length of the chain gets longer because the bushings wear, and the space between them gets longer. Technically, that is not stretching. But the chain does get longer.
Exactly (more or less), so the effect is still the same.

Chain "stretch", regardless of whether it's a cam chain, rear chain, or any other drive chain, is rarely ever the result of plastic stretching of the plates. It's virtually always a wear thing. However, Morse type chains like cam chains have no bushings; the plates run right on the pins.

The cam chain I took out of my desert racer ('06 YZ450, probably its 3rd one) had over 15 months of use on it, and was not perceptibly worn at the pivots in any way that I could measure. It did show some wear at the drive faces of the teeth, however, and if that wear is allowed to go to an excess, it can wear the crank sprocket to a dangerous point.

The big risk with cam chains is when the links start binding. It is when this begins to happen that the chain becomes prone to skipping time.

Either way, it's a cheap, fairly easily replaced part that can cause a disastrous failure if it decides to. Not worth the risk, if you ask me.

not meaning to thread jack or anything, but as long as we're on the subject what would you guys consider is a good interval for changing cam chain tensioners? I recently had timing jump on my bike, is replacing chain and tensioner at the same time a good idea?

It's a good idea, but the answer varies with the year model. What's yours?

Well actually it's not even a wr, it's an 06 kx250f. There wasn't much action in my thread in the kawi forum so i had to search elsewhere for some more helpfull people:ride:. I guess i will go and order a new tensioner anyway, better to be safe then sorry.

Ohhhhhh.......that's just mean!!!! Getting us Yamahammers to help you fix your Kawasucky!!! Maniac

25 hours is way too short of an interval for a typical weekend warrior. Unless you race, or bounce the rev limiter a ton I wouldn't see any reason for changing it that much. I had well over 500 hours (7500+ miles of ALL trails) on my cam chain before I first broke into the engine to do valve seals and a re-ring. I trail ride only, don't rev but tend to lug the engine. It was only marginally worn/"stretched" lengthwise, but the sideways bend was noticeable. I didn't really answer the question, but that is my experience on a '01 WR426.

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