[Rohnsman]

I cleaned and lubed my chain today and also adjusted it. I'm at about the #4 mark on the adjuster. I found at that spot it seemed just a tad loose to me, but just one notch up from that it seemed a little too tight. Neither spot seemed "just right" and because of the notches on the adjuster, there's nothing in-between. So...My question is....if you're going to err one way or the other, is it better to have the chain a little too loose or maybe a little too tight?

 

[lizrdbrth]

Err toward the loose side. Our clunkomatic transmissions don't like to shift well with excessive slack but if it's too tight you'll destroy the output bearing when you hit a bump. The chain effectively gets shorter as the shock is compressed.



I have my own method for definitively determining proper chain slack if you're interested, but it's a bit of work and far too anal for some.

 

[Rohnsman]

I'm glad you said that as that's what I did - left it a tad loose. I figured if it were too tight, something might break. It seems to shift ok, so I figure I'm good. I'll check it again in a while and see if anything has changed.



Dare I ask about your referenced "method?"

 

[lizrdbrth]

I warned you it was anal. Pertains to any bike with a chain. Sometime when you're really bored drop your shock and choose your own reference point so you never have to wonder where to take the measurement.. It's pretty much the only way to guaranty you won't tear anything up.



http://tw200forum.com/index.php?/topic/2008-chain-slack-measurement



I realize that hardly anyone is gunna do it, but any time you change sprocket ratios, lengthen a swingarm, lower or lift the rear of a bike the ratio at which your chain slack becomes critical changes. It also determines the limits of how much you can lift/lower a TW (or any other bike with a chain for that matter) before you'll need a tension roller, and another reason to rethink that Blaster shock swap. This is also how manufacturers determine proper chain slack to print in their manuals.



The other reason I do it is because YAMAHA wrote our manual. Just sayin'. I'd highlight all the incorrect info in that manual but I'd run out of red ink.



If you're going to use the manual's spec the correct location for taking the measurement is the middle of the entire bottom run of chain. A lot of people mistakenly use the middle of only the visible part of the chain run or the middle of the swingarm as a reference point.

 

[PalmStateCrawler]

I took a thin piece of wood and drew a nice little ruler on it to show chain slack. Mark the measurement on it and use it when adjusting the chain. It also has a deck screw in it for adjusting the valves. Just a thought...

 

[frog13]

I warned you it was anal. Pertains to any bike with a chain. Sometime when you're really bored drop your shock and choose your own reference point so you never have to wonder where to take the measurement.. It's pretty much the only way to guaranty you won't tear anything up.



http://tw200forum.com/index.php?/topic/2008-chain-slack-measurement



I realize that hardly anyone is gunna do it, but any time you change sprocket ratios, lengthen a swingarm, lower or lift the rear of a bike the ratio at which your chain slack becomes critical changes. It also determines the limits of how much you can lift/lower a TW (or any other bike with a chain for that matter) before you'll need a tension roller, and another reason to rethink that Blaster shock swap. This is also how manufacturers determine proper chain slack to print in their manuals.



The other reason I do it is because YAMAHA wrote our manual. Just sayin'. I'd highlight all the incorrect info in that manual but I'd run out of red ink.



If you're going to use the manual's spec the correct location for taking the measurement is the middle of the entire bottom run of chain. A lot of people mistakenly use the middle of only the visible part of the chain run or the middle of the swingarm as a reference point.

Ok,I'm probably missing something here Mr. Lizrd. "middle of the entire bottom run of chain".Are you saying to take measurements along the entire run on the bottom?....if so,wouldn't one get different measurements due to sprocket proximity. So,on the bottom run,if you choose to measure in between the front and rear sprockets this is not the correct method?.

 

[lizrdbrth]

You're correct.



So if you're using the underside of the swingarm as a reference point the closer you get to the front sprocket the shorter the distance between the underside of your swingarm and the chain. Take the measurement at the wrong point and your chain adjustment will be wrong. That's cool within reason as long as it's on the loose side, but if it's on the tight side it can be disastrous.



The midpoint between the center of the output shaft and the center of your rear axle on the bottom run of chain is the accepted standard point of measurement for slack. The actual center of the chain run is on the curved part of the swingarm with a 14/50.



Now let's add a 55T sprocket and 4 links of chain. Now the middle of your chain run moves rearward by half of two 2 links, or almost an inch.



Now let's put on a longer shock and use the stock slack adjustment range. There goes your output shaft (and/or your spine) the first time the swingarm goes horizontal. In order to keep the chain from jamming when the shock is compressed you risk chain derailment when it's extended.



If you do your own setup you can determine the point of measurement for yourself. Say for instance you want to use a line drawn through the forward chainguard screw, which is easily accessible and visible. Pull the shock, set the chain for free movement at the furthest point in the swingarm's arc, put it back together, record the measurement at the first screw with the bike on the sidestand and use that measurement and measuring point forever.



Lot of to do over nuttin', but use the middle of the chain with the factory rec's for slack.

 

[jontow]

I recommend ratchet straps and a long imaginary line through the bike.



Use the ratchet straps to compress the rear suspension until your imaginary line looks straight from your back axle through the countershaft forward. You'll have to pick a reference point forward on the engine to use as your third point; and a yardstick or piece of pipe might help you "draw" your imaginary line. Stop ratcheting when all 3 points make a straight line.



This is when your chain is at its tightest point.



Oh yeah, forgot to mention: this is probably easier on a bike with a cyclerack. If not, you can still strap from the swingarm to the subframe under the seat, it'll just be more annoying.



I think it accomplishes lizrdbrth's anal method without the joys of removing the shock, though. I will feel free to stand by, corrected, if I'm wrong

For what its worth, I usually roll the bike back and forth and bounce on the suspension (or have someone else do it) after I adjust to confirm everything "feels" right with the chain tension.

 

[lizrdbrth]

The only issue with using your method is that it takes considerable force to compress the shock sufficiently with a ratchet strap.



As you've pointed out this works pretty well with the added rigidity of a Cyclerack but when tried with a "naked" TW it seemed enough to bend the sub-subframe.



I drop the shock for that reason only. YMMV.



You only gotta do it once and forever, if that eases the burden.

 

[jontow]

Next point of business: always do your chain slack tests with the bike strapped in the back of a pickup truck

(yeah.. probably not)