Hayabusa chain tension

MN72Busa

Formerly known as "Zuki"
Donating Member
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I need to get this chain tension issue clarified once and for all. I believe some members here along with the suzuki manual says to adjust the chain in the folowing way.

-Place bike on side stand
-Bike in Neutral
-No weight on the bike (No rider seated)
-Find middle of chain between sprockets
-Push up on center link and measure distance (say 3/4")
-Push down on center link and Measure distance (say 1/4")
-Combine both measurments to get your total chain slack
-Slack should be between 1" and 1.25"
____

***OK here is the conflicting instructions from the Haynes Manual.

-Place bike on side stand
-Bike in Neutral
-No weight on the bike (No rider seated)
-Find middle of chain between sprockets
-Push up on center link and measure distance (say 3/4")

**That is all - No pushing down on chain and adding that number to get total chain slack.

Haynes says Chain slack should be 20 to 30 mm.


So, Here is the Question - Which method is the correct Method? I really would like to get this issue cleared up, because each method gives very different chain slack results.



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You have it right with the first one. Measure the distance from the chain pushed up to the chain pushed down. 1" of slack.
 
Thanks for the input - this doesn't make me feel very confident in my Haynes manual. Why would Haynes deviate from Suzuki instructions on such a critical issue
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#1 is the way to go...

When we (local tech and I) adjust my chain we also check it "loaded" before final torquing, you on the bike on the rear stand. This ensures you did not over tension it.
 
#1 is the way to go...

When we (local tech and I) adjust my chain we also check it "loaded" before final torquing, you on the bike on the rear stand.  This ensures you did not over tension it.
Can you explain this a little further for me? Here is my thinking - The bike is not loaded when you have it on the rear stand & you sitting on the bike.

It would be loaded if the bike were "Off" the stand and you sitting on it. And I'm guessing chain slack would vary from person to person due to sprung weight from the rider.

So can you explain to me how measuring chain slack with the rider mounted, and the bike on the rear stand gives any relative information?
 
If the rear stand is like mine (pitbull) sitting on the seat loads the suspension, you can take it down to check it as well... We've actually done it both ways.
 
If the rear stand is like mine (pitbull) sitting on the seat loads the suspension, you can take it down to check it as well... We've actually done it both ways.
I use both front and rear pitbull stands. Ok, now for the rear stand, when you have the bike on the stand, and your sitting on it, what amount of slack do you want?

Im asking because if you are suppose to have 1" to 1.25" of slack with no sprung weight on the bike, what amount would a guy want when sitting on the bike? Just enough to have some play in the chain, or is there a certain number were shooting for here?

I really appreciate the education on this issue, as I do all my own work.

Also, 1 more thing. Are you measuring your chain slack beofre or after you tighten your axel nut? And when you tighten your axel nut, do you push down or pull up on the torque wrench as not to upset the slack number? Hope that question makes sense.
 
Also, 1 more thing. Are you measuring your chain slack beofre or after you tighten your axel nut? And when you tighten your axel nut, do you push down or pull up on the torque wrench as not to upset the slack number? Hope that question makes sense.
Good question - I was about to ask the same thing. Cuz I can have the specified slack BEFORE tightening the axle nut - but once it's tightened to specs, there will be almost no slack!

I've gotten into the habit of making my chain fairly loose (almost hitting the swingarm - when I tighten the axle nut - the chain slack is about right (~1" travel).
 
yup, when "loaded" the chain is tight. I should not be so tight that you cannot move it. Try to get with a race tech and you can ask all the Q's you want. I go by feel as much as anything. I cannot go into details, no brain power today.

There are big differences between a static load, loaded, and fully unloaded tensions. The last thing you need is to snap a chain (or come off the sprocket) when coming off a wheelie or over a whoop-t-do... and it's not like the busa is torqueless either.



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I believe the amount of slack you measure is relative to the amount of force used to move the chain.
That was my question. "How much pressure do you apply to the chain to move it?"
I can get it to read whatever I want depending on how hard I try to push it up or down.
 
I use true slack... to me that is just a toe flick and the deflection of the chain, if it "just" moves, it is inside the OK zone. If it bounces with slop, take it easy until you can adjust it. You might want to get some cotter keys.
 
One thing I didn't see mentioned yet? The chain will have tight and loose spots, spin the wheel and check for variances (tight spots).

Adjust it at the tight spot.

And don't start in with the "replace the chain", after only a few miles you will have tight and loose spots, even more so if you actually twist the grip on the right.

My terbo destroys chains, I use the ZZZ and it still destroys them.

Lube the chain prior to adjustment. 20mm of deflection is what I go with, that means measured up and down. Also, recheck chain after tourqing the axle nut. Remember to adjust at tight spot in chain. If there is too much deviation, replace chain. Some deviation is to be expected.
 
Ok, here is another observation I have. I run an EK zzz chain, and when I check my slack pushing up on the chain, I get about double the measurment as when I push down.

Example:

-Push up on chain 3/4"
-Pull down on chain 1/4"

Is this normal?
 
Yes - there's this thing called gravity that makes your chain droop downward between the sprockets, so you'll always have more upward movement than downward.

Ed
 
Ok, now that I am really confused, is it or is it not ok to adj the chain with the bike on a rear stand (spools). The factory service manual states .8" to 1.2" of travel. I adj mine on the rear stand to those specs, tighten the axle nut, measure again, put the bike on the floor and measure again. It all seems to work, but I don't want to be doing something wrong. Thanks


Don
 
Val the Suzuki is right. A general rule of thumb is.. slightly loose is way better than too tight. As lomg as the chain freely moves up and down you should be good.
 
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