DRZ400SM Chain Jumping

[Davidz]

Hey guys, not really sure where to put this topic... But I'm seeking advice. 
I replaced my chains and sprockets probably 2 weeks ago, and all has been well since then. Well... That was until yesterday.
Yesterday I started noticing a slight scraping noise, comparable to that of if i took a knife at a slight angle and ran it across a section of metal. This seemed to be coming from around the counter-shaft area. The noise isn't present through the full rotation just seems like one hot spot. It also gets a bit more gruesome and more consistent the higher speed you go. Since I hadn't heard this noise before I quickly got off to check it out. Just looking at it, nothing really screamed WRONG. But I turned the bike back on, and ran it in first gear tilted on the kickstand to see how the chain was rotating. This is when I noticed that its not only making an unusual noise, it's jumping around too! Whether the noise is related or not, I can only find out once I get this thing to stop skipping around. So I recorded a video showing this jumping. If anyone can advise me I'd extremely appreciate it. I was going to install a MCCT today but didn't want to add any variables to my current problem (though I have my doubts about the MCCT having any effect on the drive chain.) Thanks for taking your time. 

[cowpie]

i would inspect everything real close and if nothing obvious pull the chain off and check things even closer .. sprockets, free rotation everywhere, if you have to pull the swingarm its a good time to check all the suspension joints out and grease them to ... my guess in the dark is you have a pin or two locked up in the chain .. probably got wet or something and sat .. it happens ..

[Decil Moto]

1. MCCT is for your CAM Chain not your Drive chain. So that will not make any difference for your problem.

2. Check both of the chain rollers 1 next to the coolant bottle and 1 down below it (it's by the swing arm I'm not next to my bike so I can't picture it exactly) make sure neither of these are chewed up, the bottom one the chain goes on top of the roller and if it's chewed up it could cause it to jump around.

3. It looks like you have alot of chain sag, have you properly adjusted your chain or is it just the vid and my bad eyes.

4. Is your rear end actually straight? Are both sides adjusted so they are even and straight with the bike? I'm not sure but maybe the rear being off line by a bit causes the rear jump.

These are all things you can try and report back!

[madchild]

It's the chain. Likely not lubed properly and a few links are seized. Replace the chain

[Mr-Adventure]

Jumping chain is not unusual on a stand or even riding/cruising on small throttle opening's, it's the nature of a single cylinder only firing on every second revolution.

Noise however is not normal, you said that you replaced chain and sprockets a couple of weeks ago, did you use a rivet type joining link?

Rivet type joining links if not installed correctly can cause a tight spot in the chain.

Not all sprockets are perfectly round, this can manifest it's self with the chain going loose tight loose, when adjusting the chain you must find the tightest point in the chain and have minimum slack a this point.  

Like already mentioned, check your chain alignment and rollers should be inspected as well.

[Davidz]

I inspected the rollers. They both look good and roll fine. The chain slack I've measured several times on several occasions since I've gotten the chain installed, and it's always been right about 1.8 inches total slack up and down, measured from the bottom pushing up towards the swingarm. Maybe in a certain spot its looser? I've never found that to be the case but I'll check again. How do you recommend finding the "tightest spot"? Check every 1/4th of the chain down? 1/8th? My rear end would seem to be straight, if not only just very slightly off with the adjuster being ever so slightly out more it looks like on the left side. Up for debate though. Ill add pictures to get your opinion on that. The chain uses a clip type link. It would be truly unfortunate to find out that this brand new chain is hosed after only 2-3 rides on it. I spent a while picking out a good pair of what I hoped to be long-lasting sprockets and chain. Other than this there has been some sort of rubbing on the rear caliber, sounds a bit metallic and you cant hear or feel it on the road, only if the engine is off, in neutral and rolling it in reverse at a specific point. I think the chances of this being related is minimal, as I could not seem to get rubbing to go away completely no matter how aligned the caliper was. I've been tampering with the idea of taking it back off and inspecting it, but maybe it's just me, but on the 05 with the smaller swingarm then the new models, its a total b****  to try and get the rear wheel, and especially the caliper off, and back into place. Certainly caused a huge headache last time.   I did just relube the chain, though i would think it unnecessary having lubed it under a 100 miles ago. Worth a shot I guess. Can't really test as it would wake up the whole neighborhood at this hour.

Edited November 24, 2015 by Davidz

[Davidz]

P.S. Does anyone know the part number for the rear sprocket bolts, or where to get them. I had to drill one out and have yet to find a good replacement (or set).

[ohgood]

P.S. Does anyone know the part number for the rear sprocket bolts, or where to get them. I had to drill one out and have yet to find a good replacement (or set).

just buy some used bolts from eBay. tighten the NUT on the back side of the hub, NOT the bolt. tightening the bolt puts unusually heavy stress on the bolt at the counter sunk section, and breaks it.

your chain hopping is 100% normal and expected. every thumper will do the same thing when there is no load on the drive train.

the only way to make it happen less is with a cush drive rear wheel or to drag the brake. again, it's completely normal.

the noise you mentioned could be a wheel bearing in failure mode, our your cs bearing failing. drop the chain off front and rear cogs, and turn the wheel slowly, searching for the noise. then put pressure left and right, top and bottom on the tire while turning the wheel and check for slop.

at the cs check for slop in/out, up/down, front/back. there should be none.

never ride a worn wheel bearing.

it's $20 to repair and literally will save your life.

one more time.... a chain hopping while on the stand (or at constant speed with no load) is completely normal.

[Davidz]

The idea of a failing bearing did cross my mind with this. I will inspect and report back. Will I have to take the countershaft sprocket off to inspect this bearing? I could imagine that the sprocket and bolt would help it not show up... with that said, I've locktite'd both the nut and sprocket... so that's easier said than done. Thanks for clearing up the chain hop bit. It seems that its new information to quite a few people (including myself). 

[maxpat82]

chain spinning with motor on wil always look like so.

 

look like of have quite a bit of slack there....and IMO you have one too many link : adjuster should be way more forward then that with a new chain.

[bigduff]

Just a thought - any chance you bought mismatched chain and sprokets?  I.E.  a 520 chain with 525 sprockets? just wondering.

[ptgarcia]

Chain looks too loose to me, even with it on the stand.

[trevorchappell]

That chain is way too loose!

[Davidz]

I thought the general consensus was that the chains on these bikes ran pretty loose since they have a ton of suspension travel and you dont want it to be too tight when your suspension is near the top because its hard on the drive train. Regardless, now I've got the slack set to 1.5in (yes i know the spec is 1.6-2.0) of travel up and down measured from the bottom side of the swingarm pushing up as it seems that everyone believes my chain is too loose. This is with it on the center stand though... I will triple check it before it gets any street time. And of course the chain still jumps but we've covered that already. I checked for any play on both wheels and I tried to get the countershaft to move and it's solid, but again this could be only due to the fact that the sprocket and nut are locktite'd, and i would think that the spacer behind the sprocket would be blocking motion at that point. Could be wrong though and it's just a-ok. I have yet to be able to get it on the streets still, as its currently 20mph winds, heavy gusts, and its 39 degrees so.... 
As for parts, yes all of my parts are 520. Im using: 

 

DID 520VX2GB-110
Sunstar 2-357741
Sunstar 32315

Edited November 25, 2015 by Davidz

[maxpat82]

go ride and have fun!

[Davidz]

Okay guys so I just got the bike back out, the chain didn't seem to be causing any more issue than before, although I would say it feels a bit different (potentially worse?) with the chain that tight. Oh well that's really not what I'm worried about at this point. My primary concern is the noise coming from that area of the bike (countershaft). So much so I wish I could either rename or create a new topic, since we've established the normality of chain jumping. It's quite possible that it's actually coming from the engine itself. I captured some footage on my go pro, and it was a bit hard to hear, but I did get a fairly good capture at a certain point of the noise. Seems the noise goes away when the clutch is pulled in. Here's that footage. The noise is best heard at 0:04, 0:09, 0:16. There's a bit of wind noise in some areas, and that shouldn't be confused for the noise... But I'm sure you'll get the idea. This was the best I could do to try and get an example of the noise. 
 https://youtu.be/X_jbA_5G5Gk

If that wasn't enough to go on, I also took it off the helmet mount and put the thing right near the countershaft. Not sure how definitive the footage is but I figure the more evidence the better and since I have it I might as well post it.
https://youtu.be/MzvN1qMHN-E
 

Edited November 26, 2015 by Davidz

[BillDirt1]

Chain is too loose.  Needs lubed, or replaced & frequent lubrication. 

[Davidz]

The chain has been tightened further than even spec already. I think I've eliminated the chain itself as a culprit because the noise seems to be eliminated entirely once the clutch becomes engaged. Even if I'm doing 50-60mph, and the noise is quite painful, engaging the clutch at this speed eliminates the scrape noise it seems.

[BillDirt1]

The chain has been tightened further than even spec already. I think I've eliminated the chain itself as a culprit because the noise seems to be eliminated entirely once the clutch becomes engaged. Even if I'm doing 50-60mph, and the noise is quite painful, engaging the clutch at this speed eliminates the scrape noise it seems.

Ok, I just thought your chain looked loose.

Now the noise issue would bother me, enough to dis-assemble the entire clutch package & inspect.

[Davidz]

Ok, I just thought your chain looked loose.

Now the noise issue would bother me, enough to dis-assemble the entire clutch package & inspect.

I think I will do that throttle5. I am unsure if that will be the rout cause, or if it will be inside the engine. Do you have any other recommendations? I have a much better video now showing the noise. Listen at 0:15-0:19. It's very clear.

https://youtu.be/1rjFC6kS4o4

 

I am applying a releasing the throttle there and you can see it happens when I apply the throttle. Do you have any thoughts on this?