Thoughts on this chap's experience with chain slider wear?

How to have your holiday ruined :-(

ADVRider RR

Bike was overloaded, under-sprung, and the chain was too tight. All are avoidable.

I agree, and have always felt this way about this issue.

Take a look at the wear marks on that slider and swingarm and imagine the angle the swingarm has to be at in order to make those wear marks.

That's me.

Overloaded: arguably not. I weigh 75kg with gear, and had about 20kg of bagage. 95kg total. Some guys weigh more.
You could argue about the lever effect of having the luggage it further back. But people have done longer trips with more luggage on the WR250R, with no problems.

Under-sprung: stock spring, at max preload. People have done longer trips with more luggage on the WR250R, with no problems.

Chain too tight: not. First chain was tightened to Yamaha spec. Second, brand new chain was even looser than that.

Swing-arm angle: After putting the new chain on, I test drove around while hanging off the side to try to have a look at the sprocket. I could see the chain touching the slider.
That's a bike with no luggage, at max-preload, loose chain, and a light rider. Speeds between 10-20km/h, level ground.
I tried combinations of tighter chain and looser chain, and left it at looser.

I sketched in red how it looks like when driving.
Stock sprockets.

The chain getting stiff or kinked can do this too, this would explain the first one but not the one after you changed the chain.
Others have had this issue and had to switch to 14 tooth front sprockets along with 47-50 tooth rear sprockets. Making both sprockets bigger keeps the chain away from the slider. I have 13-48 gearing, the larger rear sprocket changes the angle of the chain a bit on its own too keeping the chain further from the slider.

My bike did this but not as quick as yours, I patched the slider and its been fine since.
The only difference I see with our patch jobs is my patch was a little over 2 inches long so more of the chain hits it.
Here's a link to how I patched it. https://wr250rforum.forumotion.com/t12499-how-to-rebuild-the-chain-slider

I do not believe the drive chain will saw through the slider and swingarm material and leave those neat-looking wear channels without being forced into it under tension.

What I proved to myself with my 2008 WR250X years ago is that, even with the specified or even a bit more than the specified chain slack, when the swingarm is pivoted up enough the chain will be in the exact position to do this and there will be enough tension on the drive chain to do this.

The location of the swingarm pivot is lower than most bikes, and the chain slider material at the bottom is much thicker than that of other bikes in anticipation of this.

I could see a sticky chain do that, follow the curvature of the front sprocket into the swingarm. What's up with that threaded hole for the case saver? Are those grooves from the chain also?

Maybe somebody can mount a couple of cameras down there to catch this in action over many miles of use.

arnoldus wrote:

Overloaded: arguably not. I weigh 75kg with gear, and had about 20kg of bagage. 95kg total. Some guys weigh more.
You could argue about the lever effect of having the luggage it further back. But people have done longer trips with more luggage on the WR250R, with no problems.

I weigh 111 kg (245 lbs) with riding gear and my slider looks almost like new with 6500 km (4000 miles) on it.

arnoldus wrote:

Under-sprung: stock spring, at max preload. People have done longer trips with more luggage on the WR250R, with no problems.

"Max preload" isn't a setting and "other people" don't matter much unless their bikes are set up like yours.  The only way to verify proper spring rate is to adjust rider sag to 95mm to 100mm (with full riding gear and luggage) and then verify static sag (with no rider or luggage) is 20mm to 35mm.  If you set rider sag to the above specs and static sag is less than 20mm you probably need a stiffer spring.  This is basic suspension setup methodology, not my own secret formula.

arnoldus wrote:

Chain too tight: not. First chain was tightened to Yamaha spec. Second, brand new chain was even looser than that.

Have you verified that the chain isn't tight when the swingarm is fully compressed to where the chain is at it's tightest position?  The "Yamaha spec" measures clearance from swingarm when the bike is on the sidestand.  This method is useless if the bike is under-sprung or if the sprockets aren't stock diameter or if the bike has been loaded with more weight since sag setup.

I'm not trying to start an internet argument with you, but you're obviously doing something wrong with your current setup.  If you can see the chain rubbing the slider then something isn't adjusted properly. As you noted plenty of other people are riding heavily loaded WRRs without having this problem.

I didn't do a spring sag test. The preload adjuster is screwed all the way down.
It could very well be too soft / worn, but that wouldn't be my first bet.

I had a guy heavier than me sit on the bike, with all the luggage on it. The chain did not touch the slider when stationary.
Only when moving does it get thrown against the slider.

I'm going to buy a new sprocket set, with a 14 front and a 45 & 46 rear (= 3% less than stock ratio, and 1% less than stock).

dicklane625 wrote:

What's up with that threaded hole for the case saver? Are those grooves from the chain also?

Yes, that's from having the chain very loose. Doesn't help either :-)

Any chance your bike is lowered?
That makes the chain hit the slider pretty early in the travel.

When you maxed-out the rear spring preload, does that result in little to no rear suspension sag under the bike's own weight (also known as "free sag")?

Not lowered, afaik. No yamalink or such.

I'll get the bike back on Thursday, and I'll do some sag tests this weekend.

Its the sticky chain causing the slider wear. Nothing else. I've tried many sprocket combos, including a brief stint at 14/48, and numerous ways of tensioning the chain. Loose or tight, big or small sprockets front and rear, riding many miles with a passenger even, and had no chain slider wear until I get a sticky link that doesn't want to play nice.

Case in point, this past weekend's ride from Fairbanks, AK to Dawson City in the Yukon. When I left I had almost 0 wear on the slider but when I got to Dawson it was about halfway worn through. The master link (rivet type) was kinking badly, as were a few others. Soaked the chain in WD40 that night and in the morning, and again in chicken and in Tok on the way home, and most of the links are loose again and no more slider wear all the way home. I did have to do a chain adjustment to tighten in Tok, but I figured leaving it loose couldn't hurt as long as it wasn't skipping.

BTW, I love the TKC's on your bike. Looks great, the 140 is a nicer looking tire for a sumo than the 130.

I would have to say you may rival one of my riding buddies for how much stuff you loaded up on that bike for the trip. Amazing mules at times.

The longest trip I have done on my WRR was 2 weeks riding the COBDR in Colorado and I probably had about 60% of what I see loaded up on your bike. Even then when I hit the half way point I mailed back about 30 lbs of stuff that I realized I would never use (including a gas can).

That was about 4 years ago and I have gotten a bit better in packing lighter. But then again I am not adverse to hitting a hotel when I see one and I do not tend to pack much in the way of food because I can stand to loose a few pounds and usually I can find a decent meal on the trail or a gas stop.

skierd wrote:

Its the sticky chain causing the slider wear.  Nothing else.  I've tried many sprocket combos, including a brief stint at 14/48, and numerous ways of tensioning the chain.  Loose or tight, big or small sprockets front and rear, riding many miles with a passenger even, and had no chain slider wear until I get a sticky link that doesn't want to play nice.  

Case in point, this past weekend's ride from Fairbanks, AK to Dawson City in the Yukon.  When I left I had almost 0 wear on the slider but when I got to Dawson it was about halfway worn through.  The master link (rivet type) was kinking badly, as were a few others. Soaked the chain in WD40 that night and in the morning, and again in chicken and in Tok on the way home, and most of the links are loose again and no more slider wear all the way home.  I did have to do a chain adjustment to tighten in Tok, but I figured leaving it loose couldn't hurt as long as it wasn't skipping.  

BTW, I love the TKC's on your bike.  Looks great, the 140 is a nicer looking tire for a sumo than the 130.  

It seems everyone has a firm and differing opinion on the cause :-)
I put a new chain on, there were no stiff links... Will inspect again when I get the bike back.

rsteiger wrote:

I would have to say you may rival one of my riding buddies for how much stuff you loaded up on that bike for the trip.  Amazing mules at times.

The longest trip I have done on my WRR was 2 weeks riding the COBDR in Colorado and I probably had about 60% of what I see loaded up on your bike.  Even then when I hit the half way point I mailed back about 30 lbs of stuff that I realized I would never use (including a gas can).

That was about 4 years ago and I have gotten a bit better in packing lighter.  But then again I am not adverse to hitting a hotel when I see one and I do not tend to pack much in the way of food because I can stand to loose a few pounds and usually I can find a decent meal on the trail or a gas stop.

I have the stock tank and had to use the canister a couple of times. Gas stations closed, etc. (Have since ordered a 3 gallon IMS tank)

The only thing which I really had too much of was MRE's. The little drybag is almost entirely MRE's. I could have left those out in retrospect.
- Most stuff in the tank bag could have been relocated to the drybags, but it was handy to have them there.
- The saddlebags were not that big, and the left one had to be emptied of small things due to the hole.
I have ordered Tusk side racks now, so I can fit other, larger bags, lower down.

Bit of a late reply, but... meh.

I'm only just on my third front slipper at 36k. I'm very heavy at 110kg without gear, running 13/48. Full suspension travel is used every day I ride the bike, several times a day or more. However, I'm REALLY fussy about front sprockets and ditch them as soon as they start to hook or wear significantly. I've noticed that unless you do this, the worn sprocket picks up the chain and thus accelerated slipper wear occurs. It does not take much.

I, too, run a lot of chain slack to cope with all the shit that rides around the sprockets under the chain; sticks, pebbles, really hard prickles and so on. My bike has, up until now, spent basically zero time on sealed roads.