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Next summer I plan to spend 4 months in the Yukon and Alaska; my TW rides on the back of our expedition vehicle as its ‘recon’ vehicle and escape pod. We will be pushing into the remotest places we can find [definitely way off pavement], so the TW will have to plow thru more mud than I think I ever wanted to know even exists.



I decided to replace the stock chain with an o-ring DID 428Vx122 in hopes that both cleaning and overall maintenance in a sloppy environment will be simpler and less frequent.



Everything’s strung and connected, and I am at the point of adjusting chain slack; I have a few questions:



1. Should I expect ‘some’ stretching of this brand new chain? How many miles before this is likely to stabilize?



2. Does anyone have authoritative information on the correct slack range for a 2010 TW? Is it ‘better’ to err toward a more or less slack chain if one cannot hit the range just right?

As has been noted here previously, Yamaha has published conflicting numbers for desired slack adjustment. My 2010 Owners Manual gives a range of 1.38”—2.36”; the main/1987 Service Manual gives 1.2”—1.6”. [The 2001 supplement is silent on this matter.] I am inclined to go with the 1.38”—2.36” range, both because it is a newer number and because I have the impression that it is better to err toward a looser than a tighter chain. I have found that the eccentric ['snail'] cam on my rear axel forces me into a jump from 1.625” to 2.125” in one click.



3. I am mounting the new chain with 1300 miles on the bike. After cleaning the sprockets my visual inspection revealed only a minimal polish mark [slightly smooth appearance] on the teeth of the sprockets; certainly no deformation, elongation or sign of significant wear. Any reason to question not replacing the sprockets [just asking as I have seen posts here about this]?



[P.S. I have done a comprehensive search of the Forum on "chain slack measurement", so please don't suggest that I do this as a reply!]
 

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If you want "perfect" chain adjustment on a TW (or any other bike) ignore the service manual and get the real deal. Here's how to get it:



Jack the bike up on a stand. Preferably a bike lift.



Remove the shock.



Swing the swingarm through its arc by lifting the wheel until you find the spot where the chain is at its tightest. Adjust the chain to be just slack enough that the swingarm will move freely past this point.



Re-install the shock and take the bike off the lift.



Bounce the suspension a few times, then take a slack measurement with the bike on the ground from a point of reference that you can access easily. Doesn't matter where it is along the swingarm as long as you use the same spot every time.



Find your spot, write down the measurements and it will be your ideal minimum slack for the life of the bike.



To get the "ouside" measurement (maximum allowable slack before adjustment) back the snail adjusters off by one click. Take another measurement at your "spot", then never allow the slack to exceed that number.
 

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1. Get a fat chick to straddle the bike and hold it vertical.

2. Block both sides of the swingarm so the back tire is off the ground.

3. Get the fat chick to sit on the bike slowly, so the suspension compresses to the point the chain is as tight as it will get. Do not let the fat chick sit to heavily on the bike because the chain will loosen up at the limits of suspension compression.

4. Spin the tire slowly and see if the chain slightly tightens and loosens as the sprocket turns (most sprockets are slightly out of round to prevent harmonics.)

5. Position the wheel so the chain is tightest, pull the wheel all the way back, then ease of one notch on the adjuster.

6. Rotate the tire until the chain is as loose as it gets, knock the fat chick off the bike, remove the blocks, place the bike on the side stand, and raise the back wheel off the ground by lifting and supporting the frame, not the swingarm.

7. Measure the slack in the chain.



If you measure the salck in the chain with the bike on the side stand different loads on the bike will affect the measurement. A consistent and repeatable measurement requires unloading the rear suspension.



If you don't have a fat chick, two skinny chicks will do, or a fat guy, or loading the bike on a trailer backwards and using tiedowns to load the suspension, or a bear sitting on the seat, or lead in the top box, or ... .



the chain is tightest when the countershaft, swing arm pivot bolt, and axle are in a straight line.
 

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Do the work. Pull the shock.



That is all.
 

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OK, tell us about your expedition vehicle.
 

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Am going to try the fat chick and pulling the shock methods and report back which is the most hazardous to the health.
 

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LOL, thanks for the laugh about the fat chick....I've always just sat on seat with as much weight as possible, have bike vertical and check for slight chain slack. Done this for years, never had any chain problems....
 

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What it all boils down to is countershaft, swing arm pivot, and axle is a straight line and the chain not too tight. Doesn't matter how you get them lined up, just so they are. I always use a few bars of gold bullion on the rack. Works great.
 

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My way is cheaper to feed......



Apparently my method is too technical for some. For the rest of you, running the swingarm through its arc and knowing at what point of adjustment you'll rip out your output shaft on a bump might be helpful info. Takes about 15 minutes including pulling the shock.



The problem with our snail adjusters is that they force you to run excess slack before you can adjust again without ripping out your output shaft on a bump. Not a real ideal system for best chain and sprocket life, but cheap to manufacture and close enough for government work.



Qwerty, virtually ZERO sprocket manufacturers deliberately produce out-of-round sprockets for harmonics or for any other reason. Perfect concentricity is the goal of the industry and anything less is the mark of a cheap product and poor quality control. I've heard you present this notion as fact in the past and if you can substantiate otherwise I'd be very interested in hearing it. The potential for obtaining a crappy, out-of-round sprocket only makes the case for knowing the proper settings unless you just want to always err on the loose side, which is good enough for government work as well. Just not real kind to sprockets.



I'm gunna go quiet on the subject with a trick question:



Where's the middle of your chain?
 

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Discussion Starter #10
lizrdbrth and qwerty



thanks for the replies, and qwerty's last post explains why the seemingly Rube Goldberg process.



What slack range do you end up with when you trim it out your respective ways?



I'd like to know how close it comes to the factory recommendations!



Also, what about the new chain stretching over the first miles? much?



thanks, John
 

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I run 55T sprockets. My slack will be different than yours.



Don't get the idea that I run around with a ruler in my pocket, constantly checking my chain tension. I don't. I just run through the shock-pulling drill once with every new-to-me bike or when I change sprocket sizes because the factory rec's are almost always wrong.

Absolute knowlege of when it's too tight is the more critical of the two measurments. If increasing the snail by one notch exceeds that you'll have to put it back where it was until it wears some more.



You can expect some stretch during the first 500-1,000 miles or so. In my experience it will be minimal with a decent o-ring chain and new sprockets, sometimes as little as one bump on the snail. After that it's just a matter of checking it periodically as things wear. Certainly not as demanding as an open chain, but they can stay in adjustment for so long that you take it for granted for longer than advisable and end up eating a sprocket prematurely, so keep a good eye on it, regardless of whose measurements you use.
 

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My mid-quality o-ring chain hasn't stretched enough to need adjustment yet at over 700 miles. Anything above bargain bin c**p should not stretch too much after install.



I used a ratcheted tie-down strap up & over the rear frame to pull the drive sprocket, swingarm pivot, and rear axle into position to find the needed chain slack. The bike was sitting on cinder block & 2x4s with both wheels off the ground.



Word of advice: When using the "Fat Chick Method", injury can be avoided by not calling it that while in hearing range.

 

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I have over 5000 miles now on my DID O-ring chain with no adjustments. the chain is still exactly (or damn near) where it was during after installation.



I spray it down about every 500 miles, it's a little dirty but still functions fine.
 

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heck i went 15,000 miles on a Regina O ring chan on my street bike and only had to adjust it once right after it broke in. All i ever did was every 300 miles hit it with purple power scrub it down with a stiff bristle nylon brush or if it was bad i hit it lightly with a brass brush, Rinse chain well, make lap around the block to dry and warm chain, relube entire chai, wipe off excess, let it sit for at least 1 hour, the go ride.



Never washed the bike but that chain was spotless lol



For the adjustment of the chain i just sat on the bike reached down and felt slack. I have never run a chain guard though so its easier to do sitting on the bike.
 

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Sprocket manufacturers could make sprockets so perfect they have zero tolerance, but they don't. Close, but not quite. Not quite is enough nonconcentricity to prevent harmonics. Sprockets are significantly closer to concentric than 40 years ago, but intentionally not perfect.



Yes, the instructions in motorcycle manuals about chain slack are often not a good compromise between strain on the countershaft and wear as the chain flops against other parts.



Yes, the snails' calibrations are quite too much.



So far o-ring chains have needed adjusting after 600-1000 miles. Next 2 or 3 adjustments are done when the rear tire is replaced, not because they need adjusting. When the chain needs adjusting between tire replacements (starts rattling or looks saggy, I've never actually measured chain slack with a ruler), it's starting to stretch and I order another chain and sprocket set. I don't wait for the chain to wear out, just go ahead and replace it. That way I don't ever have to worry about wrapping a chain around the hub and locking the rear tire at speed or breaking the chain and launching it through the engine cases.
 
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