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Opinions needed for correct chain tensioning

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I recently found that my swing arm at the bearing end damaged heavily by my chain. This is a first for me. In 47 years of riding I've never had this happen before.

The chain had eaten through the top slider and into the swing arm itself and eventually into bearing race. This happened with a relatively new and good chain that had been adjusted (1" of slack top and bottom) before a two hundred mile ride. The damage occurred during that ride. The slider and swing arm were fine prior to the ride. The chain was also lubed.

So, I know that bikes like the WR250R and CRF's require a tighter than spec chain to keep this from happening. Will I need to do something like that? Tighter than specs?

Lets NOT get into chain quality and types or to lube or not to lube.

Please just focus on chain tension please, let me know your thoughts, and what you think is the right way to do it. Do you tighten yours more? Less? and why?

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i had a stock chain which was fine until a guy at work who really likes my bike told me the chain looked way too loose. i went about one inch on the slack. big mistake. next thing i know the chain started kinking and eating up my sprocket cover. there was also a noise that drove me crazy. i replaced the sprockets and chain, leaving them at the 2.5" slack recommended by the manufacturer. they have not stretched at all in 1000 miles.

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I recently found that my swing arm at the bearing end damaged heavily by my chain. This is a first for me. In 47 years of riding I've never had this happen before.

The chain had eaten through the top slider and into the swing arm itself and eventually into bearing race. This happened with a relatively new and good chain that had been adjusted (1" of slack top and bottom) before a two hundred mile ride. The damage occurred during that ride. The slider and swing arm were fine prior to the ride. The chain was also lubed.

So, I know that bikes like the WR250R and CRF's require a tighter than spec chain to keep this from happening. Will I need to do something like that? Tighter than specs?

Lets NOT get into chain quality and types or to lube or not to lube.

Please just focus on chain tension please, let me know your thoughts, and what you think is the right way to do it. Do you tighten yours more? Less? and why?

I hope that wasn't your new swing arm Chuck. Was it? That would really suck!

Mike:ride:

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The Clymer manual says 1.6-2.0", reading posts like this about chains eating thru the swingarms I run right at 2.0"

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The right way to learn what is right for your motorcycle (any motorcycle) is to go thru the whole process.

Motorcycle on a work stand. Disconnect the rear suspension so you can move the wheel thru the full range of suspension travel. Move the rear wheel so the rear axle, swing arm pivot, and countershaft sprocket centers are all in line. This will have the chain at the tightest point. Now adjust chain for about 1/2 of slack. Put it all back together and measure chain slack with the wheel at full extension. Record this value. This is what you use for future adjustments. Don't go tighter then this.

Since chain sliders last many thousands of miles, chain adjustment may not of been your original problem. My slider has at least 40,000 miles on it. In normal operation the chain does not ride on the slider. A small sprocket (like 13 or 12) will put the chain closer to the slider. As Eddie asked, what size front sprocket?

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what front sprocket size?

1" slack is too tight for me.

Hey Eddie & Noble,

I am running 14/41 sprockets

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I hope that wasn't your new swing arm Chuck. Was it? That would really suck!

Mike:ride:

Mike,

No, it wasn't the new one...haha. Just trying to prevent the same thing from happening again. Thanks for asking though.

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14/41 sprockets

this will definately increase slider wear.

check often and replace as needed.

with the bike on its wheels push down on the chain at the back of the slider. it should just touch the rear edge of the slider.

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this will definately increase slider wear.

check often and replace as needed.

with the bike on its wheels push down on the chain at the back of the slider. it should just touch the rear edge of the slider.

Thanks Eddie, is there another combination that will give me the same gearing and less wear on the slider? Also, I put the bike on its wheels after adjusting the chain as Noble suggested above. I then checked where the chain hits the slider as you asked. Iit engages it almost the entire length of the slider. The chain is only about 1/8" off the slider near the counter sprocket. So, it is my assumption that I need a taller counter sprocket or rear sprocket to get the angle up a bit correct?

Edited by vstromcharlie

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This will have the chain at the tightest point. Now adjust chain for about 1/2 of slack.

I am assuming you mean 1/2" of slack correct?

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A 14x41 gives a ratio of 2.92 to 1

A 15x44 gives a ratio of 2.93 to 1

It might save a lot of wear and tear with a 15x44 sprocket combo.

A 15x43, at a ratio of 2.86 will lower HWY cruse rpm even more than 14x41

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A 14x41 gives a ratio of 2.92 to 1

A 15x44 gives a ratio of 2.93 to 1

It might save a lot of wear and tear with a 15x44 sprocket combo.

A 15x43, at a ratio of 2.86 will lower HWY cruse rpm even more than 14x41

I found the gearing commander page and I'm playing with it now. I often slab to my riding location where I am on gravel, two track and occasionally single track. I like my current gearing set up for single track but I am very open to changes to keep this from happening again. I have a 2300 mile trip scheduled this summer and most of it is gravel. I need to have this sorted by then.

I'd like to maintain a top slab speed of 65-70mph but be able to crawl at 3.5 or so mph in first gear on the trail. I run a 130/90/18 on the rear of the bike most of the time (occasionally a 120/90/18 when I can't get the former).

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I run a 15 tooth front, 14 for woods riding. It appears I am running my chain with a lot more slack in it than what I'm seeing here.

I was mostly woods riding and replacing rear hub bearings quite often when I adjusted the chain for 1.5" of slack. While bench racing a while back, an "Orange" bike factory rep (can I say KTM in this thread?) mentioned they run chains fairly loose. They checked tension by pushing up from the bottom, and leaving about 10 mm clearance between chain and bottom of the swingarm.

I know the swingarms are different, but it seems to be working for me. I have not replaced a rear hub bearing since I started running loose and I've never, knock on wood, thrown a chain. I'm doing a lot less riding that takes the entire shock stroke so I may start running a little tighter.

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I'm doing a lot less riding that takes the entire shock stroke so I may start running a little tighter.

You don't have to be riding off road to reach the critical point of chain adjustment.

The critical point being between 1/3 and 1/2 way in your travel when there is an imaginary straight line between the counter shaft, swing arm pivot and the rear axle as explained by Nobel in how to adjust your chain.

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what front sprocket size?

1" slack is too tight for me.

I'm running 14/47 gearing

What slack (in metric) am I looking to adjust on this setup Eddie???

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I'm running 14/47 gearing

What slack (in metric) am I looking to adjust on this setup Eddie???

50mm:thumbsup:

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I'm running 14/47 gearing

What slack (in metric) am I looking to adjust on this setup Eddie???

I just used Nobles procedure (page one) to adjust mine then I wrote down the resultant slack with the bike on it's wheels. Now I can duplicate it.

I ordered a 15 tooth counter shaft sprocket to be on the safe side and get the chain off the slider as much as I can.

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I just used Nobles procedure (page one) and adjusted mine then I wrote down the slack with the bike on it's wheels so I can duplicate it.

I ordered a 15 tooth counter shaft sprocket to be on the safe side and get the chain off the slider as much as I can.

I've seen this term cs or counter shaft sprocket a few times.

What is it and how is it different from a regular sprocket???

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