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I have noticed that my drive chain is slapping up and down very violently during certain conditions. It happens worst when the bike is going around 40mph in 5th gear. It really makes a huge slapping noise then. If I shift into 4th it seems to dissipate. I think it also does it to a lesser degree at speed in 5th gear.

I originally thought it might just be the chain, but it happens with my new one now. I'm trying to figure out the cause. If the rear tire is out of balance could it cause this? I know that the last I had it balanced they couldn't get enough weight to counter the rimlock, so it does hop a little bit.

Another thing is that the swingarm bearings haven't been greased in years. I do plan on doing this soon (bearings ordered). I'm not sure how this would effect it, but anything is possible I guess.

I would really love to get this issue resolved, as it is beating the heck out of my chain, and especially my chain guard. I've already had 3 (yes, count em, 3) chain guards fail.

It's slightly difficult to gauge the problem when rolling down the road on the bike, so this is getting slightly frustrating! Pretty much all I can see from my quick glances is that the chain is indeed going up and down very quickly, and that maybe the rear tire is hopping up and down as well.

Thanks for any advice/wisdom:worthy:

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Did you change the sprockets when you changed the chain? ๐Ÿ˜

If the links don't settle easily into the sprocket teeth, the chain will chatter and buck, and quickly ruin itself and what's left of the worn sprockets.

Fwiw, a rear tire should never be out of balance "because of a rimlock". Did they bother to mount the tire so the light spot was at the rimlock?*

It's hard to believe that a reputable shop would let a seriously out-of-balance wheel go out the door; can't fathom them not being concerned about the rider or even the liability. ๐Ÿ˜

(The yellow paint circle on Dunlops denotes the light spot and should be mounted at the tire valve. Metzeler uses two red dots for the same designation)

Here's a street bike link that writes about it: http://www.sportrider.com/suspension_settings/hands_on/146_9512_tire_mounting_and_balancing/index.html

* sometimes it's better to put the light spot next to a rimlock instead of the valve.

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Sometimes 2 rim locks oppositeceach other help the balance 90 deg from the valve. Mine took a ton of weight to ball and makes a weird noise over 50. Chain slap has more to do with chain sprocket interface than tire an you should always replace both together. Are sprocket teeth hooked looking? Easy way to tell they are worn.

Any dirt bike with lots of travel will have some but see how loose your chain is. How did your 3 chin guards fail? Is rear sprocket bent and wobbling causing the chain to go all over the place? Spokes loose?

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I have noticed that my drive chain is slapping up and down very violently during certain conditions. It happens worst when the bike is going around 40mph in 5th gear. It really makes a huge slapping noise then. If I shift into 4th it seems to dissipate. I think it also does it to a lesser degree at speed in 5th gear.

I originally thought it might just be the chain, but it happens with my new one now. I'm trying to figure out the cause. If the rear tire is out of balance could it cause this? I know that the last I had it balanced they couldn't get enough weight to counter the rimlock, so it does hop a little bit.

Another thing is that the swingarm bearings haven't been greased in years. I do plan on doing this soon (bearings ordered). I'm not sure how this would effect it, but anything is possible I guess.

I would really love to get this issue resolved, as it is beating the heck out of my chain, and especially my chain guard. I've already had 3 (yes, count em, 3) chain guards fail.

It's slightly difficult to gauge the problem when rolling down the road on the bike, so this is getting slightly frustrating! Pretty much all I can see from my quick glances is that the chain is indeed going up and down very quickly, and that maybe the rear tire is hopping up and down as well.

Thanks for any advice/wisdom:worthy:

Do you have much difference in the freeplay , between the tight spot and loose spot in the chain during wheel rotation...

This can cause excessive chain slap...

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Sounds like chain may be a little loose, also I noticed my bike does this to an extent when I lug it...at 40 in 5th depending on your gearing you are probably below 4K RPMs which on my bike can be a little chuggy in the higher gears.

Justa thought.

On another note, I have 35K on my bike and am still on stock chain guards. I am not the best at cleaning/lubing my chain so I have been through probably 5 or so chains/sprockets in that time but have not had to replace a guard yet.

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I havent got a chain guard on mine....

Will fit one when I can (Might make my own :S)

Mine has 14/47 gearing instead of stock 15/44, but mine lurches a bit if I try to go below 20mph in top...

Not that I do tbh, only when I was getting used to the bike ๐Ÿ˜

Just go a bit faster or change gear ๐Ÿ˜

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I have noticed that my drive chain is slapping up and down very violently during certain conditions. It happens worst when the bike is going around 40mph in 5th gear. It really makes a huge slapping noise then. If I shift into 4th it seems to dissipate.

You're luggin the engine, mine does it too no matter how tight the chain is.

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Alright, I'll try to address all the questions

The guys at the shop put on as many weights on the rim as they could, but it still wasn't enough.

Does have new sprockets with the chain.

The chain shouldn't be loose, I've had it looser.

I'll get pictures of chain tension and the tire weights this afternoon:thumbsup:

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Mine has always done the same thing with a properly adjusted chain, I think it has to do with the engine pulses when you lug it. It never does it when the RPM's are up no matter what gear your in.

Me, I just live with it as IMHO it is not hurting anything but then again I don't have the chain guard on my bike.

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Did you change the sprockets when you changed the chain? :eek:

If the links don't settle easily into the sprocket teeth, the chain will chatter and buck, and quickly ruin itself and what's left of the worn sprockets.

Fwiw, a rear tire should never be out of balance "because of a rimlock". Did they bother to mount the tire so the light spot was at the rimlock?*

It's hard to believe that a reputable shop would let a seriously out-of-balance wheel go out the door; can't fathom them not being concerned about the rider or even the liability. :banana:

(The yellow paint circle on Dunlops denotes the light spot and should be mounted at the tire valve. Metzeler uses two red dots for the same designation)

Here's a street bike link that writes about it: http://www.sportrider.com/suspension_settings/hands_on/146_9512_tire_mounting_and_balancing/index.html

* sometimes it's better to put the light spot next to a rimlock instead of the valve.

Actually...the shop they I had do mine argued with me...they never balance dirt bike tires...they told me it was ridiculous. I made them do it anyway. As I recall...it took 4 big spoke weights and 2 large tape weights, 1 for each side to balance out the rimlock.

Yes it can be done...they just need to use both kinds of weights.

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Actually...the shop they I had do mine argued with me...they never balance dirt bike tires...they told me it was ridiculous...

Well, I guess it doesn't matter to some... lol

Takes an extra 5 minutes and $2 in lead. sheesh.

To their credit, I do see their point in a way though - MX tires do wear quickly and tear off a knob and you've gotta be out of balance again.

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Well, I tightened the chain up a little bit from the loose side to the tight side of the spec, and the slapping noise is almost nonexistant. I did, however, notice that under some conditions (not all the time) the chain still does have a very violent up and down motion still. I'm not quite sure what to think, it's obviously not good for the chain or anything around it. I really can't think of a cause though. I guess when I replace my swingarm bearings I'll do some checks to see if everything is still alligned, and see if the bearings have anything to do with it:excuseme:

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Adjust the chain to factor spec's, your lugging the motor at 40 in 5th gear. It's a one cylinder thumper, they all do it in 5th gear if lugging the motor with the chain ajusted properly. 5th gear 50ish. 1st gear, ride as slow as you can at idle only, just barell moving, when the piston fires watch the chain jerk or jump.

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  • 10 months later...

I basically have just one question. Everyone talks about cutting the hole to be 3x3 or larger according to the master 3x3 article that is in the faqs. Well while I was under my seat today to do some wiring for my dual sport kit I was looking at the snorkel and it pops out.

Does no one else have this in their bike? Is it a DRZ400K only that has it? Here are some pictures of it. One of me holding it and the other of it out completely and measured. Probably 3.5 x 5.5.

Snorkel

DSCN0767.jpg

Without

DSCN0766.jpg

Of course I have a jetting question. Only because the master list didn't include jet listings for the K model. I was going to get a 142.5 main and a 25 pilot. Mine has the FCR carb in it stock as far as I can tell. Though it looks a bit different. So I'll take a picture of it just to be sure if someone would be willing to take a look at it. I've got a blue pull lever on mine and don't have a clue what the hell it does.

So any answers would be great. And the FAQ's are great but don't cover what I am asking here.

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