chain noise on '03 crf

this has probably been addressed somewhere on this site, but i can't get the answers i'm looking for. and i asked the question on a thread opened by someone else about engine noise and got no response. anyway, my question is, do you guys all have chain noise at low rpm while taking off, etc? it's like the chain is slapping. is this something that can be fixed? and is it normal? thanks in advance!

Sounds like it is too loose. You can check your mud flap on the chain side and if it is getting hit by the chain then it's too loose.

I don't know what else it could be, but Loose.

It's tighter than a 2 stroker. :)

make sure you have the chain adjusted properly, then just goose it and go.... :)

Put your bike on a stand and adjust the chain so there is exactly 1" of slack on the top in the middle between the sprockets. Clean between the slider and swingarm until spotless then use RTV silicone to glue the slider to the swing arm top and bottom. These 2 steps should do it.


thanks for the info. i forgot to mention that i'd adjusted the chain to spec. it stretched a lot the first ride out of course. but even after the adjustment, it made the noise. i'll try that method dbm. did you do this? thanks again.

I have noticed this also with my 02. I seem to notice it more when the bike is cold.

My first thoughts were chain slap, but I too had made all the proper adjustments.

I think the noise is in the motor, but I haven't been able to pinpoint it.

If anyone could elaborate on this, I would be greatful. :) <font color="yellow">

I also noticed this on one of my first rides on the bike. There were 2 Honda shop mechanics at the track and I asked them to listen to it and see what they thought of it. Neither one thought it was something to worry about. They mentioned the XRs are notorious for cam chain noise, and that maybe the CRF is the same way. I have a lot of hours on my '02 and there's been no problems yet, so I wouldn't worry about it.

I too had the same noise, then I tightened the chain a little tighter then spec and it was gone.

when i tightened the chain to spec, it seemed like it was too tight. i got the bike new and have only had it a few days (barely broken in). i guess it's a little different than other bikes regarding chain tension.

i had a ktm 520 before this, and it made some nasty chain noises at low rpm's too. just part of the package. guess i'll just have to put more twist in the wrist! :)

well, thanks for the input guys. glad to know the beast is alright.

Best way to determine how tight your chain should be adjusted to:

Remove the shock linkage bolt from the swing arm so the swing arm/wheel can be raised by hand through it's travel.

Locate the tightest spot in the chain as you move the wheel through it's travel stroke.

Adjust the chain to very little slack in this position.

Reconnect the linkage.

Remeasure the slack with the wheel extended (as normally done) and this will be your new minimum slack adjustment.

Too tight a chain is bad bad bad. Don't just tighten it up under spec to get rid of the slap noise unless you do this at least once.

I've also noticed a similar noise on my 03 CRF.

I agree with MX600 and the mechanics he had ride his. I really doubt there's a problem. I think you get the slap noise at low RPMs because your lugg'n and thump'n that chain (and cam).

If I really try to lug my 02CR250 I can get a similar noise out of it. Of course it won't lug near as well as the CRF.

Maybe I'll try the glue deal if it bothers my too much.

Most of the noise is the slider slapping against the swingarm surfaces. If you use RTV silicone to glue the pieces together the noise will almost completely stop. The silicone acts as a damper between the hard surfaces.


Remove the shock linkage bolt from the swing arm so the swing arm/wheel can be raised by hand through it's travel. Locate the tightest spot in the chain as you move the wheel through it's travel stroke. Adjust the chain to very little slack in this position.

That is correct, and here is where it is tightest... When the suspension is completely unloaded/topped out. Therefore you just need to put your bike on the stand with the rear wheel off the ground and that is the tightest spot. Adjust in just a little play at that point because it will only get looser as the suspension compresses. On most bikes the front sprocket center line, swingarm pivot center line, and rear axle center line all line up when the suspension is roughly halfway compressed. When all three of these things line up that is the chains tightest spot. On the CRF the swingarm pivot centerline is slightly below the centerline of the front sprocket so therefore all three line up with the suspension is unloaded rather than halfway compressed... make sense?

The first couple of rides on my bike I was bothered by the chain noise until I figured this out, now it will be one year old this month and I'm still on my original chain slider pad and I don't have chain noise. If you think the chain is too tight it most likely is not. The bottom line is that if you adjust the chain like you would another bike then it's too loose and it'll be noisey, eat the chain slider, and rub the inside of the frame.

You don't have to go through disassembly to adjust your chain properly. The '03 as well as the '02 chain is at it tightest when the suspension is fully extended (on a stand) It get looser as the suspension compresses. As long as you have some slack when its on a stand (I have an inch or even a little less) its fine. Be sure and test for slack along the whole length of the chain by spinning the wheel and making sure there is slack at all points. The CR250 and 125 are the same as well on '02 and '03.

Motogreg, you just beat me to it. Ditto what motogreg said :)

you guys are awesome. thanks for the info!

I tighten mine where 3 fingers are a tight fit right behind the chain slider on the swingarm. This has seemed to eliminat that noise.

Tightest in the fully extended position is good to know. I have actually never done the method I described on the CRF yet but have done it on my YZF and it was a good thing to do. The YZF compresses several inches before it is at it's tight spot. Guys were breaking hubs and getting loose sprocket bolts from over tight chains.

Sounds like as long as there is some slack in the chain it won't be too tight on the CRF. Honda recommended 1" may even be too liberal. Sure makes things alot easier.

Wooo Hooo, don't know if I have just been sleeping or what, but I have fought with this chain thing over and over... but never seem to be able to get it right. My shock gard has been chewed all to h@&*, because of running it too loose.

A friend of mine said I was running it too tight before so I started using the 3 finger method, but now that I know that the tightest spot is fully extended, I will make it an inch.

Okay so are you doing an ~inch just after the slider or at the end of the slider?

Thanks a ton for the info... This is why TT exists.

It's Chain slap for sure. Just give it a bit more gas instead of labouring it.

ditto on what wy4tt said. you guys are awesome.

this weekend i will adjust to 25mm. just a tad under an inch.

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