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How to Measure Chain Slack?


Cjanssen83

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Cjanssen83

Which point do I measure from? Red, green, or blue?

And I go diagonally, not straight down, yes?

How much pressure should I be putting on the chain with my finger?

 The manual and the service manual are kinda vague in my opinion. 

It’s a bit jerky at times shifting gears, like it’s trying to catch up…assuming tightening my chain will help?

IMG_0623.jpeg

Edited by Cjanssen83
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sweetscience

Measure slack at the tip end of the second crest.  Just left of where the green mark begins.  You can check this by measuring the midway point between the front and rear sprockets' chain contacts.  Measure slack perpendicular to swingarm.  Put as much pressure on the chain until it can no longer stretch, which is not much.  The important rule is to measure slack at the TIGHTEST point on the chain, as you will see there are loose and tight spots.  So, I go with a 56 mm slack at its tightest spot on a paddock stand.  Or 51 mm with the bike on its side stand.

Happy trails! 

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ElGonzales

Blue, shows the drawing in the user manual, using the sidestand.
15N pressure with the finger (or whatever) to the chain, says the user manual. 15N = 1,52 kg   (15N / 9,81 m/s^2)

 

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sweetscience

Yes, I stand corrected, the blue zone is the right choice.  +1 to ElGonzalez.

The rollers on the chain will contact the track of the chain guide first. 

 

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Cjanssen83
5 hours ago, ElGonzales said:

Blue, shows the drawing in the user manual, using the sidestand.
15N pressure with the finger (or whatever) to the chain, says the user manual. 15N = 1,52 kg   (15N / 9,81 m/s^2)

 

How do measure Nm with finger pressure?

…I googled and found that 1 Nm is like holding an apple, so I just push down on the chain with the force of 15 apples?

…I feel like I’m in elementary math class again, lol!

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ElGonzales

N is not Nm  ;) 

The pressure - force  you should put onto the chain is 15N, which corresponds to a weight of 1.52 kg. Thats the weight of  ~1.5 liters of water.
You can convert it in any other unit of measurement, 3,30693 pounds for example.

Don't blame me, thats the instruction of Yamaha and you asked the question

Kick the chain up with the tip of your boot, if  it moves approx. the width of a cigarette box chain slack is allright, this is my method   :D

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2 hours ago, ElGonzales said:


Don't blame me, thats the instruction of Yamaha...


...Kick the chain up with the tip of your boot, if  it moves approx... width of cigarette box...chain slack is allright, this is my method   :D

So much yes here for the cig method

Kudos to @klx678 as a source, he checked the perpendicular distance with swingarm at bottom & top of travel, because he knows manuals have been wrong in the past.

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Another tip for chain slack I read here a while back (I don't remember who posted it to give them credit, unfortunately) is that you can use a credit card to measure. The manual calls for slack between 51-56 mm (or 2.01-2.2 in) and your typical credit/debit/gift cards are ~54 mm (or ~2.1 in) so almost the middle of proper slack. 

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Triple Jim

I have  a wedge of wood I cut so at one end the chain is at 2" slack, and at the other end it's at 2.2".  If the 2" end goes in, but it doesn't go all the way though to the 2.2" end all is good. 

You just have to cut the wood at the slack specs minus 1/2 of the chain width.  With the stock chain, that's 1.71" at the short end and 1.91 at the long end.

 

 

chain_go_no-go_gauge.jpg

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Right or wrong, I've been using the blue line - When I push the chain up toward that lip, if it touches the lip, it's time to tighten the chain.... seems to work for me. 

 

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Triple Jim
4 minutes ago, FZ not MT said:

Right or wrong, I've been using the blue line - When I push the chain up toward that lip, if it touches the lip, it's time to tighten the chain.... seems to work for me. 

 

That's actually a pretty good way to check it.  I just adjusted mine today with my wooden block, and if I use one finger to press the chain up pretty snugly, there's just about 0.2" of clearance.  More fingers and I can make it touch, so the one finger thing is relevant.

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If in doubt, make it looser. It won't hurt anything. Talked to a young guy once that was terrified of letting his chain get to loose and worried it would derail, get tangled and make him crash. Reddit had him worried to death. 

 

Unless your chain is obviously drooping like this, it's never gonna derail from being a bit loose. You're fine.

loose_chain_gs_800_rblr_1000.jpg.50e15856aae5f4dbc13e3310ea925f39.jpg

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15 hours ago, Triple Jim said:

I have  a wedge of wood I cut so at one end the chain is at 2" slack, and at the other end it's at 2.2".  If the 2" end goes in, but it doesn't go all the way though to the 2.2" end all is good. 

You just have to cut the wood at the slack specs minus 1/2 of the chain width.  With the stock chain, that's 1.71" at the short end and 1.91 at the long end.

 

I like the Go/No-Go  gauge functionality of your wood block. It's very much K.I.S.S. method.  I'm gonna make my own now. Thanks for the idea Jim. 👍

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DewMan
 
Just shut up and ride.

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