Pretty hard for me to tell by looking at a chain in motion.
What I do to check chain slack is
1) put the bike on a swingarm stand, slowly rotate the rear wheel feeling the chain tension on the bottom run. There will be a tight spot. Position the wheel so that the chain is at the tight spot.
2) Use a 15" steel ruler set behind bottom and top run of chain. The belly pan makes a great place to set the ruler so it stays in place.
3) pull the top run up tightly, then release it. This will pull the excess slack out of the bottom run. I do this every time I measure just so the tension is consistent.
4) Pull the bottom run down. I do not pull hard. Maybe ~3 lbs pressure. Measure the distance the chain travels. If you want to remeasure this, do the top run tug first as in step 3 so the tension in the bottom run is consistent.
5) Push the top run up, measure. Again, just about 3 lbs pressure. if you want to recheck the top run slack measurement, give the bottom a quick tug first so that the tension in the top run will be consistent between measurements.
6) Add the travel measurement from the bottom run to the travel measurement of the top run. Should be between 1.5 and 1.3 inches. Loser is safer than tighter.
A little too loose is better than a little too tight. My busa chain had twice the recommended slack and it was nowhere near coming off the sprockets. It felt a bit jerky at times, maybe but it would have to be very loose to come off the sprockets I think. Too tight and the chain will stretch when the rear suspension compresses as you go over a big bump. It could also break if it stretches too much and then it obviously will also come off the sprocket(s) destroying your engine or locking your rear wheel.
I have 1.75 inches slack right now on the 14 and I intend to tighten it up a bit tomorrow. This will prolly require a very small adjustment. Perhaps just 1 flat to 2 flats turn on the hex heads of the chain adjuster screws. You do not turn them much at all. It is amazing how much the chain tightens with a very small adjustment.
The reason I take the measuremnets from both runs and add them is because if you pull and push on the bottom run to take the whole measurement as suggested in the SM, you will find it impossible. The chain hits the swingarm chain guide and you don't get he full range. Same thing happens if you try to use just the top run.
Final tip, expect your chain slack to tighten up about 1/4 inch more after you torque the axle nut. I think the swing arm squeezes together and pushes the wheel back a tiny bit more pulling the chain tighter.
Whenever you estimate in adjusting or measuring, go more toward LOOSE.
* Last updated by: Rook on 5/5/2012 @ 11:10 PM *
08 MIDNIGHT SAPPHIRE BLUE ZX-14 Now Deceased, will be resurected
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