I have 2 questions;

1) Where is the best (safest) place to take the chain slack measurment and why?


2) After taking the measurment is it common practice to make the adjustment while the bike in on a bike stand or should the whole evolution happen with the bike sitting on its side stand?

 

I follow the owner's manual for location, and check it on the side stand. Be sure to find the tightest spot by rolling the rear wheel while checking slack.

 

Yeah, I know the manual says to check slack with the bike on the side stand, but honestly my bike has some static sag when on the side stand. And near as I can tell, it's never quite the same. I'm a lot more confident of my actual chain slack when the bike is on a small lift stand. With that the rear wheel will drop to full extension, and the slack will always be more consistent. And as IDRIDR suggested, it's wise to check the slack in several places, as chains are seldom the exact length throughout all the links.

 

Isn't the chain the tightest at full compression? You really have to be careful if checking it with the wheel at full extension...that's where it is the most loose. Making it too tight will cause premature wear and possibly ruin the oil seal on the countersprocket shaft.

 

Counter shaft, swing arm bolt and axle. When they are lined up it is as tight as it will get.

 

Yep, the 60mm or so, depending on your model and gearing is calculated on that tight spot that turnsleft refers to at countershaft, swingarm pivot, and axle alignment. Really, unless your bike has perfectly stock gearing as delivered from the factory, one should probably compress the rear suspension to that alignment point and check that suitable slack and ideal tightness is achieved. Chain tightness from that point under suspension compression or extension gets looser. When you find just enough slack at those 3 alignment points, you can then find what the maximum slack is with the rear suspension fully extended. This is your benchmark from then on. Changing front and rear sprockets can alter the recommended tension slack measurement to some degree.

 

If you are in doubt of chain slack, just have a fat guy like me sit on it after you make the adjustment. Remember that as the suspension travels down in the back the chain does indeed get tighter. Many a chain has snapped in half because of being too tight to begin with. And its amazing how far these things travel when doing whoops or small jumps. Side stand, and then you should be able to fit a couple of fingers between the chain and the swingarm.

 

Yowsers. This sounds more complicated than it is. My method is to sit the bike up vertical and off the stand. I stand beside the bike on the right side and lean over the bike trying to compress the rear suspension as much as I can. I then grab the chain on top of the swing arm and try to get a healthy inch of freeplay.

On TNC's photo I would say that it is too loose but wouldn't know until some weight was on the bike.

Throwing off a too loose chain cause really screw some stuff up.

Kawi chose to use a stupid cotter pin on the axle nut frequent adjustments must also include frequent new cotter pins.

 

Highbeam, I agree that it looks loose. I run a 14/47 gearing, so instead of just going with the recommended 55-60mm setting, I cinched the suspension down to that countershaft, swingarm pivot, axle alignment point...tightest point...and set the chain slack at a safe minimum at that point. When I released the cinch strap and with with wheel off the ground at full extension, my optimum chain slack turned out to be 60mm. 55mm would have been a tiny bit too tight. Where you have your axle adjusters and chain length set can also make a difference, of course. My chain is running at an ideal tension at 60mm at the recommended measurement location on the swingarm.

 

I have the 09 klx 250 s. I bought the tech manual it says to measure dead center between the front and rear sprocket. Measuring from the bottom of the chain. The alowance for my model according to the manual is 35 - 45 mm. The bike is still stock..no mods.

Thanks for the info. Here's what i'm getting from you kind fellows.(insert beer here)

1) On the bikes side stand or on a bike lift, Compress the rear suspension to it's tightest point which is when the countershaft, swingarm pivot, and axle align and check that suitable slack and ideal tightness is achieved according to the bike manual. Measure dead center between the front and rear sproket. Adjust accordingly

2) a) De- compress the rear suspension leaving the bike on it's side stand. Measure the Chain slack. This measurment becomes your benchmark from then on. This way there is no need to compress the suspension each time a chain slack measurment is made.

OR

2) b) De- compress the rear suspension leaving the bike on a bike lift with the back wheel off the ground at full extension . Measure the Chain slack. This measurment becomes your benchmark from then on. This way there is no need to compress the suspension each time a chain slack measurment is made.

How's this sound.

Thanks again.