Loose chain

[Pab]

My chain was horribly loose and making bad noises (slapping in to things), so i tightened it. a day later its pretty much back to being loose again, is this common? I got everything back tight. Maybe a walkthrough on chain tightening, would help me see something i forgot. I have an 82 650e btw.

[Anonymous]

Did you clean the chain really well and then lube it first? If you did and it slacked off in a big way you are probably in need of a new chain and sprockets. The usual GS spec for chain slack is about 3/4" but I can never get it to stay there.

I'd like to know what the "time to adjust" value is.

Steve

"I've been splined!!!"

[earlfor]

Re: Loose chain

On the lower chain run between the front and rear sprocket, you want about 3/4" slack below a straight line. This is not 3/4" slack with the bike on the centerstand or leaning on the sidestand. This is 3/4" slack with the bike upright, sitting on both wheels with the rider seated on the bike, plus any gear/bags you may carry. In other words, the bike in the loaded condition.
Since it is difficult to sit on the bike and check chain tension, the suspension compression and swing arm arc with the bike sitting on the centerstand and no rider results in having to set the chain with about 1 1/2" of slack in the unloaded condition.

With the bike on the centerstand, set about 1 to 1 1/2" of slack in the lower chain run. The slack needed will vary with your weight. I weight about 160lbs, and set 1" of slack below a straight line between the sprockets, That means the chain can be pulled 1" below a straight line and 1'" above a straight line with my finger in the middle of the chain run.

Lube the chain and take the bike for a ride of 20 miles or so. When you come back, put it back on the centerstand and check the slack. If it has increased, note the increase. That will be the amount of slack the chain requires and you will then always set that amount.

A chain does not require pretension to operate correctly. The countershaft sprocket pulls the chain onto the sprockets, so there is no reason to set a tight chain as far as function is concerned. If your sprockets are in align as they should be, there is also no chance of the chain being thrown off since the engine is pulling it down onto the sprockets. Noise is the only problem with too loose a chain, or if very loose, it can strike the swingarm crosspiece on the lower run.

You want to run a chain as loose and free as you can and only tight enough to suppress whip/vibration and noise. Whip is only a problem if there are galled and sticking pins in the chain. there should be no stiff links.

A #630 chain measures 3/4" from pin center to pin center. If you used 96 links of #630 chain, the chain stretched out would be 72" long. For this length of chain, once the chain is stretched to a length of 72 3/8", it is considered worn out and continuing to use it will only destroy your sprockets. One indication of a worn out chain is when adjusted with the correct amount of slack, it stretches quickly (within a couple hundred miles) An "O" chain in good condition and adjusted correctly will not need
adjustment for probably 8 to 12 thousand miles.

I almost never need to adjust the chain on my 1150 and it has gobs of torque. :-)

Earl

My chain was horribly loose and making bad noises (slapping in to things), so i tightened it. a day later its pretty much back to being loose again, is this common? I got everything back tight. Maybe a walkthrough on chain tightening, would help me see something i forgot. I have an 82 650e btw.

[Detman101]

Great info. I will use this soon.

Dm

[Jethro]

I keep my chain quite loose. 1 1/2" to 1 3/4" of slack on the bottom run. I get no noise, no problem shifting and I never need to adust it between tires.

I leraned the hard way on my 81. New sprockets and chain are somewhere on the schedule!