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Chain slap.

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I just picked up my new CRF250x. It was a left over 05'. I'm just now starting to play with it a little bit, and I notice that there is a lot of chain slap. I notice it more when I am in a higher gear like 3rd or 4th, with lower RPMs. I checked the chain tension, and I think that it is plenty tight. Anyone else experience this, and what can I do to fix it?

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Just a layer of caulk on the underside of the swing arm? Any specific type?

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Another easy solution is use 1/8" foam insulation with adhesive tape on one side. Cut it to width, and about 6" long, undo the two top screws of the chain guide, slide the insulation between the swing arm and guide, re-install the two screws, and your done. No more noise.

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I had that problem in the beginning as well and posted here on TT and learned that a bike with a linkage suspension needs less chain slack for the suspension to work properly - or it slaps. My buddies with KTM's have to run their chains WAY looser than mine - because they have no linkage. Tighten it up some, it won't slap anymore. You only need about two fingers of play. Any more and it slaps. Keeping it adjusted properly will also add to chain and sprocket life.

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Really in effect, by shimming the chain guide up. You are tightening the chain anyway.

You are tightening it at the chain guide, instead of at the axle. That sound right?

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I had that problem in the beginning as well and posted here on TT and learned that a bike with a linkage suspension needs less chain slack for the suspension to work properly - or it slaps. My buddies with KTM's have to run their chains WAY looser than mine - because they have no linkage. Tighten it up some, it won't slap anymore. You only need about two fingers of play. Any more and it slaps. Keeping it adjusted properly will also add to chain and sprocket life.

I guess I don't understand what link vs. no link has to do with chain adjustment?

Not trying to be a smartass, but isn't the arc that the swingarm travels & the position of the c/s sprocket-swingarm pivot dictate the amount of chain slack needed?

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This is good feedback. I haven't had a chance to play with it yet. Any other suggestions?

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This is good feedback. I haven't had a chance to play with it yet. Any other suggestions?

Try adjusting your chain to two fingers slack - only, and see if it still slaps. You can read about it right on your swingarm or in the manual. When your bike is newer, you have to adjust the chain a lot more frequent than when it gets broken in - like before every ride and you won't have that annoying slap.

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I run my chain slack at 3/4" at the tightest point in the chain with the bike on on the stand.

You have to spin the wheel and check it at several different spots because it will vary.

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I had that problem in the beginning as well and posted here on TT and learned that a bike with a linkage suspension needs less chain slack for the suspension to work properly - or it slaps. My buddies with KTM's have to run their chains WAY looser than mine - because they have no linkage. Tighten it up some, it won't slap anymore. You only need about two fingers of play. Any more and it slaps. Keeping it adjusted properly will also add to chain and sprocket life.

He's right. I had a KTM and ran about three fingers of slack. I set my Honda up the same way and had bad chain slap at low RPM under load. At two or two and half fingers of slack, no more problem.

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I used clear rtv so you cant see it

Mine is adjusted at 2 fingers. If I get RTV sealer, do I just add it on the chain guide?

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the front chain guide that wraps the front of the swing arm is held on by phillips head screws. Remove the screws, clean the swing and chain guide very well with solvent, then apply the silicone on the swingarm under the chainguide and re-attach with the screws. wipe the excess.

The noise is generated by the chain guide slapping the swingarm when the chain slaps the chainguide.

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hmm my chain hits the inside of my frame tho

MIne has done this too, I now have a new chain on so I have been trying to think of a way to see if the frame is still getting hit, I may tape or paint it.

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It may not be chain slap. I have an o4 and I can here the carb slide rattle. I thought it was slap until (I think Dirt Bike) I read to look at the carb I did and it was.

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