Swingarm eaten by chain

ACR wrote:

I've been bit by the chain eating the swing arm issue.  The local welder was able to repair the damage, which went as far as touching the bearing.  So, with a new chain slider, properly adjusted slack ( removed shock from linkage method ) I've ridden about 1,000 kms.  I checked the slider for the first 150 kms at different intervals, all seemed well.

After the last ride, checked the slider and observed extreme wear on the front bottom.  The chain is suspect at this point, so I've ordered a replacement set to see if it helps.

Slider should last MUCH longer than 1000 kms. Something is wrong.

Exactly how did you adjust the "slack" in your chain?

I put 10,000 miles (16,000 kms) on my first chain slider and it was not worn through when I changed it.

Quote :

Slider should last MUCH longer than 1000 kms. Something is wrong.

Exactly how did you adjust the "slack" in your chain?

I put 10,000 miles (16,000 kms) on my first chain slider and it was not worn through when I changed it.

Before the riding for the season began last week, I had been doing a lot of maintenance which included greasing the linkage.  What a great time to lower the bike, and since the rear shock was dangling, I would be able to easily raise the swing arm up, finding the tightest point for the chain.  From this point, the slack was set as per the updated instructions from Yamaha, and Jagrer, to 6mm.  Everything was reassembled, life was good.

While riding the back roads, I was checking the wear on the new slider at certain intervals.  Everything seemed good.  Checked a few hundred kms later, good.  Thought I had it solved.

After the 6 hour ride to the lake, and back, I checked on the slider, only to find a very deep groove.  When I raised the bike off the ground, checked the slack, there was no longer 6mm of slack, as the chain was now able to touch the bottom of the swing arm without much upward force at all.  I believe the chain to be at the end of its life, even though it looks great and has no kinks.

So, the slider has been epoxy'd, new sprockets and chain on order, and the bikes rear will be raised back up via stock adjustment.  Once everything is in place, I'll do the interval checks and go from there.  

A too loose chain shouldn't be rubbing a specific spot in the slider.
Physics says the loose chain will distribute it's length along a larger portion of the slider, and not just wear out one specific section of it.

Can you post pictures of your new slider and the grooves?

Yes sir, here's a photo before the repair.

ACR wrote:

Before the riding for the season began last week, I had been doing a lot of maintenance which included greasing the linkage.  What a great time to lower the bike, and since the rear shock was dangling, I would be able to easily raise the swing arm up, finding the tightest point for the chain.  From this point, the slack was set as per the updated instructions from Yamaha, and Jagrer, to 6mm.  Everything was reassembled, life was good.

Just a couple of observations from the peanut gallery:

1) The owner's manual doesn't suggest putting the bike on a stand and adjusting the chain tension using the tightest possible swingarm position as the base reference point.  It instructs to measure chain tension with the bike on the side stand with no rider/gear weight on the bike.  This is basically the normal static sag rear suspension position and the chain is likely looser here than where you measured it.  For your method to work you'd need to know how much slack to add to obtain the same slack as measured at the owner's manual reference point.  Sorry if this sounds confusing.  There's a better explanation with diagrams in this post.

2) The post-2008 owner's manual suggests 8 to 13 mm of chain slack, not 6 mm.

ACR wrote:

After the 6 hour ride to the lake, and back, I checked on the slider, only to find a very deep groove.  When I raised the bike off the ground, checked the slack, there was no longer 6mm of slack, as the chain was now able to touch the bottom of the swing arm without much upward force at all.  I believe the chain to be at the end of its life, even though it looks great and has no kinks.

It sounds like your chain was adjusted too tightly, which led to slider wear and/or chain stretch.  If your chain is stretched and/or worn, your sprockets probably are too.  I recommend changing them as a complete set.  They don't cost much if you don't go for bling.  I recently bought new JST steel front and rear sprockets and DID VX2 x-ring chain on Amazon for $114 all-in.

ACR wrote:

Yes sir, here's a photo before the repair.

Sorry, but I see no possible way that is caused by a chain that's too loose.

Only way I see that happening is if chain is too tight.

When your bike is on it's side stand (as mentioned in above post), can you push your chain up and have it touch your swingarm? About half way between the sprockets push up on chain. Does it get close? Quarter to half inch away?

Thanks for the information, the supersprox sprockets are in good shape but the chain is suspect at this point.  I took advice from another members post and went with 6mm originally, BUT, that was by the method of disconnecting the shock from the linkage and finding its tightest point.  I believe the tension has been on the tight side for most of the bikes life.

motokid wrote:

Sorry, but I see no possible way that is caused by a chain that's too loose.

Only way I see that happening is if chain is too tight.

When your bike is on it's side stand (as mentioned in above post), can you push your chain up and have it touch your swingarm? About half way between the sprockets push up on chain. Does it get close? Quarter to half inch away?

This evening, I adjusted the rear back up to its midpoint.  I then set the bike on its side stand and adjusted the slack to 8mm from the bottom of the swing arm while pushing up on the chain between the roller and the guide, with as close to 36 lbs of force as I could get.  I measured with a digital caliper, which isn't easy to do while pushing up on the chain.

What I've noticed throughout all of this is there is a significant difference in slack when I adjusted via shock disconnect vs. side stand method.  

The bike is sitting pretty with proper slack, ready to go for a test.  Unfortunately, the test will have to wait until the weekend when I'm off work.  Thanks for the help, I'm beginning to see the light at the end of the tunnel.

ACR, I'm not sure putting Epoxy on the slider is a good idea. Seems to me the chain will pick that up - and that can't be good.

Just thinking out loud.

gatorfan wrote:

ACR, I'm not sure putting Epoxy on the slider is a good idea. Seems to me the chain will pick that up - and that can't be good.

Just thinking out loud.

Hey everyone,

   Had a week of riding, mostly gravel roads and trails.  The trails were sand, and had mega whoops from the years of riding.  The suspension was worked to its limits while on these trails.  The 14/49 gearing is plain ol' fun.  It makes riding gravel a lot nicer, I'm not sure how to explain it, just does.  The downside is the highway running, just not enough on the top end to keep it below a healthy RPM.  Ordered the 47, which has been proven highway gearing.

After about 600 kms with the new chain/sprockets and 8mm of slack, there is very little wear on the slider.  It's actually surprising, and a relief at the same time.

Hey Gator fan.  Guess I should have been clear on what was used.  JB weld filled the wear on the slider, the new grooves are smooth and nothing is chipping, peeling or breaking away.  Chain looks to be ok, no accelerated wear from what i see.  Figure to get seven repairs out of the JB weld kit and will cost around $1.42 per slider repair.  Each new slider, shipped, is  close to $100 a pop!  

Thanks for help, hopefully I can now convince my WRR buddy on proper chain slack

Where are you getting your sliders from? Its been awhile but my last slider was something like $40 shipped.

WRXZ wrote:

Where are you getting your sliders from? Its been awhile but my last slider was something like $40 shipped.

www.yamahagenuineparts.com

Where have you been finding these $40 shipped sliders?

https://www.2wheelpros.com/shopping-cart.html

Thanks WRXY, should save a bit of money for the next time.

Cheap here aswell: http://www.boats.net/parts/detail/yamaha/Y-3D7-22151-00-00.html

I just patched/rebuilt my chain slider.
I caught it before the chain hit the swingarm but the guide was worn through.
Im doing a how to on this below in the general maintenance discussion.

Heres a pic.

Just an update on the patch job.
I've put 700-800 kms on the bike since doing this mostly offroad.
My 14 tooth sprocket wore out so I'm running 13-50 gearing now since I had a new 13 in the tool box not 14-50 like when I first patched the slider.
It wore a bit at the front the first ride then stopped wearing, my biggest concern was the patch ripping off but that never happened.
In case some one notices I know I need a new sprocket nut, it will be changed the next time the sprocket is, the side you cant see is bent in properly against the nut tho, I've had it on and off a dozen times changing gearing lol.
Heres a couple pics.

So i've been monitoring mine from afar...

First slider wore at 2300 miles, 1400 of which were on a 12/43 setup. I just purchased my next one, made zero adjustments, and threw it on.

It was toast in 120 miles. I'm absolutely furious. I ride my chain really loose. Not KTM loose, but lose, probably much farther than spec. The thing is, I've been running it that way this whole time, and haven't had an issue, so I don't know what the heck happened.


Either way, that was $43 for ONE RIDE off road, and I'm miffed.

I ordered a 13/48 setup and ANOTHER new one, and hope the new one won't wear as quick.

Swing arm looks good though. Mild cuts, nothing horrible. 1/8" deep or so.

What did the chain look like?

A kinked chain will eat the slider in one ride, especially with a 12 tooth front sprocket.

Pretty gnarly. Not horrible, but I just looked in removing the chain and realized the stock chain isn't an o or x ring I don't think. Probably kinked.

Either way, going to 13/48 from 12/43. Also industrial adhesived the bottom of the slider to the swing arm because I noticed about a 1/8" or so "gravity sag" on it. It'll be a bear to get off, but I'll manage.

Very much interested in seeing how this was repaired. I'll check the general maintenance forum. The one that just wore out might have enough meat left to save and rebuild if I'm lucky.

Hello, I have also fallen victim of a chewed up swing arm. The first 36k miles I have had no problems. I replaced the plastic swing arm protector about 10 k miles ago. I just did a long in Maine and I could hear some metal on metal noise but I thought it was from my loose skid plate..but come to find out,my chain was waaaaay too loose.thats when I noticed my swing arm was chewed up..I dropped off my bike at the shop yesterday to get new tires on and the mechanic told me he will put some JB weld on the chewed up swing arm if it's not too bad. I sure hope I don't have to replace the swing arm. I just figured I would post this. I will let you guys know if the JB weld will do the trick.

Hello, I just wanted to update my previous post.. The mechanic at the bike shop put some JB weld into the grooves that the chain made in the swingarm.. He said he did it in 3 layers.. I rode it for about 50 miles and so far so good

jason meacham wrote:

Hello, I just wanted to update my previous post.. The mechanic at the bike shop put some JB weld into the grooves that the chain made in the swingarm.. He said he did it in 3 layers.. I rode it for about 50 miles and so far so good

Jason. "plastic" JB weld is not a good repair plan for any motorcycle swing arm...

If it starts to fall out, a reputable weld shop would need to grind out and remove any lumps of jb weld that got lobbed into the swingarm cavities , as the heat from the TIG welding process would melt the "jb"weld plastic and contaminate a "real" weld and make a worse mess.

I understand that it's not a real fix. The mechanic thinks that the grooves are not deep enough to weld it or replace it. I didn't think about the JB weld getting in the way if I do get it welded. Do you think it would distort the area around where the bearings are if I do get it welded? I was thinking that I might get it welded up over the winter... Thanks for your help

Since theres a big wide bearing under the part that gets a groove cut in it by the chain, theres no need to fix it as the grooves don't hurt a thing.
Putting jb weld on is fine as is doing nothing or siliconing the grooves.

if the grooves were only that shallow i'm surprised the mechanic didn't give him the same advice..  i must have missed the pictures of the damage.

i think a few units might have been worth a weld bead or two in that big bearing area....




here is the site the picture came from{that shows a weld repair} . distortion is always a possibility when welding anything... good reason to get a respected shop to do the job if you ever "need" to get something in a bearing area welded.

best of luck with your bike Jason... they are fine machines..