KLR600 Sprocket Elbow In

I've replaced the final drive sprockets and chain on the 1985 KLR600. Here are the parts:

• JT JTF 516.15 Fifteen Tooth (Stock) Countershaft Sprocket
• OE PN 13270-1060 Sprocket Plate
• JT JTR 477.43 Forty-three Tooth Drive Sprocket
• Primary Drive PDO 520-104 Steel Chain

JT is a well known name and I usually use their sprockets. The front and rear sprockets were sold as a set on JT's eBay page for $39.55 w/free shipping. Primary Drive is RMATV's brand. This chain was a steel, O-ring type chains with a master link and cost $42.25. I used this chain on my KLR650 and found it to be sufficient. The Sprocket Plate was necessary because I found a crack in the plate on the bike. It was purchased through RMATV's OEM Parts site for $4.88.

The sprocket plate was cracked because the countershaft sprocket was installed backwards. Normally sprockets whether front or rear are installed with the teeth number faced outward. However, when a countershaft sprocket is secured by a plate (rather than a nut) the sprocket elbow is required to face inward. In the case of the JT, the number of teeth is on the same side as the elbow. The problem that whoever installed it backwards caused is that the sprocket plate was forced to bend over the elbow that caused the crack.

The countershaft sprocket fits very tightly on the shaft. I had to apply some grease on the shaft and lightly tap the sprocket with a mallet. (Note to self....if the countershaft sprocket is the least bit loose, it needs to be replaced.) The sprocket plate slides onto the shaft and then turns in a groove at with point the two M6 8x6 bolts can be installed. I used a little thread lock in that installation.

Interestingly, the rear sprocket on the motorcycle had the number of teeth turned inward...i.e. also backwards. Perhaps that was done to align with the backwards countershaft sprocket...dunno. Either way, the Kawasaki Service Manual clearly states that the elbow on the countershaft sprocket faces inward and the number on the final drive sprocket face outward. 'nough said on that. Below is the right way. I did not replace the studs or nuts, as they seemed in good condition, but I did use some thread locker while installing the nuts.

Chain Tensioning

What I really found impressive about the final drive work was how Kawasaki designed the rear axle to support chain tensioning.

Normally, chain tensioning is accomplished with chain pullers that consist of a bolt against a plate on each side of the swingarm that pushes the axle against the swingarm to tighten or loosen the chain. You have to adjust one side at a time with a typical chain puller.

The chain tensioners on the KLR600 are actually cylinders embedded in the actual swingarm through with the axle extends. Also see photo above. Each tensioner cylinder has a single mark that is aligned with a mark on the swingarm prior to torquing down the axle. 

Once the axle is torqued (69 foot pounds), the rear pinch bolts can be released allowing the axle/tensioner cylinder assembly to spin in the swingarm using a 24mm socket on the axle nut. From the left side (chain side) as the cylinders turn counter-clockwise the chain tightens and as the cylinders turn clockwise the chain loosens. It turns easy; I just have my breaker bar on it because it's easier to reach from the other side where I was measuring the chain slack. I could also use channel locks on the other side of the axle to accomplish the same thing. 

The beauty in this design is there's no way to throw off the wheel alignment when adjusting chain tension and slack.

In completing this part of the project, I made a couple modifications.

• First, I've removed the passenger footpegs. 
• Second, I've left the chain cover off although I reinstalled the lower chain guide.
• Third, by leaving off the chain cover, I need to fabricate a protective plate for the front of the swingarm to keep crud off the rear shock absorber.

Next job...fork seals!