I recently purchased a k7 600 with 7700k. The chain was in horrible shape but I managed to clean it but now im worried the chain might be too loose. The chain can easily touch the chain guard when pushed up with room to spare.
I run a minimum of 1" slack on my sportbikes, not more than 1-1/2", and obviously this can be adjusted at the rear axle. I would be just as concerned with how badly the chain is stretched, which can only be remedied by replacing the chain and quite possibly the sprockets. Take all of the slack out of the chain (press and hold down on the run of chain under the swingarm) and then try to pull the chain off the rearmost point of the wheel sprocket. A stretched chain will expose the tooth on the sprocket, a good chain will barely move.
An chain with insufficent slack will tighten like a banjo string when the axle, swingarm pivot, and countershaft are directly in line. This can restrict suspesion action (never good, and potentially catastrophic) and could even break the engine case around the coutershaft. It also excessively loads the chain and will wear it out faster. It will not prematurely wear out the sprocket teeth, at least until the chain stretches. Which is why you leave an inch slack at a minimum with no rider. Pretty difficult to check the slack when you're on the bike...
Last edited by scudzuki; 09-14-2009 at 09:14 PM.
Reason: fix my lousy typing
There should be a bolt directly behind your rearset. I'm pretty sure it holds the chain guard on, but I dont run a chain guard. But this is where I check my slack at. I adjust my chain so that when I lift up on it, it just touches the plastic chain guide. Also, after yo adjust the axel blocks, when you tighten the rear axel, it will also tighten up the chain a bit, so make sure you take this into consideration too.
Hope this helps. And as stated above, after adjusting, pull on the chain at the 3 oclock position on the sprocket. It should not pull away from the sprocket and expose any teeth. If so, your chain is junk.
Always check your chain in several spots. I check mine in 4-6 places because a chain will develop tight spots over time, and if you adjust it perfectly for one spot, there may be others where it is way too loose or way too tight. If that is the case it is time for a new chain and sprockets. There can be a little difference in spots without causing any extra damage, but if one spot is super-tight while the chain is almost falling off at another, it is toast.
I also adjusted my chain yesterday. Taking into account that the chain will tighten a little bit when tightening the axel nut, i just left a little extra slack in the chain before tightening the nut. And voila, perfect slack. I measured 26 mm of free slack in the tightest spot. I measured the rest of the chain at like 10 different spots. Just wanted to make sure i had it right.
The other spots i measured had about 29 mm of free slack, so everything is whitin specs. Also tried pulling the chain at the back of the sprocket (3 o'clock), like Joe mentioned in another thread, to check if my chain is worn. Couldn't pull it out more than 1 mm so the chain still has a lot of miles to go.
I also didn’t use the marks on the swingarm to align the rear wheel, as they are notorious for being a bit off. I used them as an indication and I measured everything with a digital caliper to align the rear wheel perfectly. I also checked if the chain goes over the centre of the rear sprocket, and that was the case.
Funny thing is, when I let the dealer service the bike at the beginning of this season they took the rear wheel of for some maintenance work. When they put it back on I think they did not align it perfectly (it was good according to the marks but still a little off I think), cause when I rode the bike and let go of the grips, the bike used to pull a little to the right. Now that I aligned everything myself the bike keeps on going strait as an arrow when I let go of the grips. So all is good now.
I'm still running the stock chain on the bike but i want to start looking for a new chain and sprocket set for the next season.
Usually the biggest giveaway of a loose chain when riding is a loud 'clunk' when putting the bike into 1st gear. Some bikes make a clunk no matter how tight the chain but if you think it sounds worse than usual on your bike, then that's a good sign the chain is loose. The bike manual should have a guide of how much slack there should be. This is measured by imagining the lower part of the chain is on a horizontal line and you should be able to move the chain a certain distance above and below that center line.
If you think the chain is loose, check the other indications suggested above and adjust accordingly. The adjusters should be in indenticle positions either side which indicates that the wheel is in line and straight. Even a slightly crooked wheel will stretch the chain and ruin the sprockets.
Also, double check the tension after you tighten the clamp nut. The chain will tend to tighten when you tighten the nut. The way to get around this is to tighten the clamp nut most of the way but just short of locking the axle, and then using the adjuster bolts. Another trick is to reverse the direction of the axle bolt and nut, which lessens the tendency for the chain to tighen with the nut is clamped down.
When in doubt, it is better to run the chain slightly loose than slightly tight.