Chain Tension

[Ysbytymike]

After my recent rebuild, I was reminded yesterday that the biggest cause of drive-shaft failure on the @T is over tightening the chain.
Was told not to tension as you would normally do for a sports bike and to make the adjustments whilst someone about the same weight, is sitting on the bike.

Is there a tread that's covered this procedure? Don't mean the actual tensioning but advice as to how much slack to leave in the chain when under load. If I leave the normal amount of slack whilst loaded, isn't the thing going to be flapping with nobody on board? What if I take a passenger, do I need to re-adjust for the extra weight?

With all the trouble I've had recently, I'm a bit paranoid about the drive shaft.

[Steve T]

Somewhere on this site, from a time way back when, there is a post that deals with chain tension in detail.

My recollection from that post is that, with all the weight off the bike, ie on it's centre stand, set the chain so that there is a 70mm gap between the top of the chain and the underside of the swinging arm, at the mid run point on the chain. When you take the bike off the centre stand, the chain should sit clear of the swingarm. I've made up a block of wood that is 70mm wide, and use it as my chain tension guide

I've used this method and never had any chain problems . . . . . . . . . . apart from the time the chain snapped on me as I headed up a forestry track into some woods . I dont think that was anything to do with chain tension though, honest

Just my ramblings . . .

Steve T

[1gear1brake]

The chain is at its tightest when the rear sprocket, swingarm pivot, and front sprocket are in line. At this point, the front and rear sprockets are at their furthest apart (the chain cannot get tighter than this no matter what weight you put on the bike as the sprockets can't get any further apart). If the wheel goes up or down from this point, the rear sprocket gets slightly closer to the front sprocket and the chain gets slacker.

To satify yourself absolutely that your chain tension is correct, you can do this:


Put your bike on its centre stand. Undo and withdraw the bolt shown above. The swingarm can now move unhindered by the rear shock. Put blocks under the rear wheel until the two sprockets and swingarm pivot are in line (ie the two sprockets are at their furthest apart). Now adjust your chain so that you have the 'normal' inch or so of movement. Reassemble the shock linkage. Ride your bike happy in the knowledge that your chain tension is perfect .

I'm not suggesting that you do this every time you want to alter your chain tension but do it once, then measure the slack yourself once it's reassembled, then you'll know for future reference.

[simon c]

Here are a few methods for checking chain tension from the German AT website. I don't know how good your German is but you can get there with the pictures and google translate.

http://www.africatwin.de/phpbb_x/kb....e8601d6f501021

Good luck

[Ysbytymike]

Cheers fella's. Knew I could rely on this forum to solve this problem.