Need Help Chain adjustment fluctuation

dvines

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New to the thread. This is my first post. If this has already been discussed I can't seem to find it. So, here goes: I have 1,500 miles on my 2015 and decided I needed to check the chain slack. Haven't had a motorcycle with a chain since 1976. Anyway, I bought one of those chain slack measuring tools. I have the bike on the center stand. I can measure 45mm, spin the wheel 180 degrees and measure 25mm, spin the wheel another 180 degrees and measure 45 mm, etc. Need I go on? Just wondering if this is normal.
 

670cc

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It is abnormal for 1500 mile old chain. When chains get 15,000 miles on them, random tight links in the chain make the slack vary during the rotation. But for a fairly new chain, the slack should be consistent.

It is possible, but unlikely, that a sprocket is causing this problem.

I would chalk this up to a cheap OEM chain. Set your slack based on the tightest section. In other words, make sure the tight spot is in spec, and it’s looser everywhere else. A loose chain is better than a tight chain.

Someday you can replace the chain with one of better quality than the original, and hopefully you won‘t have this problem.
 

dduelin

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Chain slack is to be checked on side stand. It will have different slack on center stand with no compression of rear shock. Doesn’t answer variation question though. Listen to 670 on variation.
It’s much easier to check it on the center stand. Just add 5 mm to the prescribed “Check on side stand” range of 30-40 mm slack.
 

670cc

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I agree with dduelin on adding 5mm to the side stand slack spec if you want to do the measurement on the centerstand. I just tried to find the old threads on that subject and they don’t to come up in searches anymore.

Put simply, I adjust the chain on the centerstand and set the slack to 35-45 mm.
 

TacomaJD

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Basically you want the chain "loose enough", and as long as you can't pick up on it and slap the bottom of the swingarm, you should be good. As mentioned before, a looser chain is better than a tighter one. As long as you have somewhere around 1-1.5" of deflection at any point, you should be good.
 
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