Chain adjustment

[ja7455]

Here is my version of chain adjustment. It's just my opinion and is not the only way or the best way just what I have found to be simple and quick. 

The recommended adjustment is 43-48 mm at the center of the chain (between sprockets). The distance is between the chain guide and the top of the chain, when pulled down. I made a simple tool for measuring this distance using a piece of scrap plastic (you can use most any material you have laying around). It is tapered from 40mm to 50mm with a line drawn at the 45mm mark. In the center of the adjustment range. Just slide the tool between the chain and the chain guide till it is snug. If the chain is loose it will go past the designated mark. If it is too tight it won't advance to the desired mark. Adjust accordingly. 

Since the tool kit does not come with an axle wrench for use in the field I made my own using a 1- 1/16" (same as 27mm) box end wrench from Home Depot ($12.50). I cut off the open end to save space and weight. Not necessary though. 

Hope this helps someone. 

ja

[RIDER GUIDER]

top stuff

[Richarddd]

Cool

[straydog371]

Awesome! It's a simple functional solution that I'll definitely use.

[Alain2]

Don’t forget to unload your rear suspension before measuring the chain if you don’t have a center stand.

[Limey]

12 minutes ago, Alain2 said:

Don’t forget to unload your rear suspension before measuring the chain if you don’t have a center stand.

Manual tells you to leave it on the side stand.

Edited March 9, 2021 by Limey

[Alain2]

33 minutes ago, Limey said:

Manual tells you to leave it on the side stand.

It says that because it doesn’t come with a center stand, you still need to unload the suspension.

[AngryNeutron]

How does one unload the suspension while on the side stand?

[Alain2]

37 minutes ago, AngryNeutron said:

How does one unload the suspension while on the side stand?

Grab the tail and lift, it will stay unloaded unless you have extra weight such luggage or cases.

[AngryNeutron]

51 minutes ago, Alain2 said:

Grab the tail and lift, it will stay unloaded unless you have extra weight such luggage or cases.

Sorry, but I don't agree.  An unloaded suspension is one that does not have any weight on it, including the weight of the bike.  To unload you need to suspend the rear wheel off the ground which isn't really practical on the side stand.  This goes to my original (albeit vague and sarcastic) point.  Yamaha engineers specified the chain slack specification with the suspension loaded (i.e. on the side stand) so that's how it should be checked imo.  The slack setting for a properly unloaded suspension will be different than what is listed in the manual.

[tenerecanada]

Agreed. I wouldn't think the specs in the manual are even relevant if you are unloading the suspension.

[AngryNeutron]

1 hour ago, tenerecanada said:

Agreed. I wouldn't think the specs in the manual are even relevant if you are unloading the suspension.

Absolutely correct.  Not to get all engineerey (it's a word ) on you but here is how I understand it:

The swing arm is pivoting at a different location from the front sprocket.  As the suspension is loaded the chain becomes tighter as the relative distances between the front and rear sprocket change along the arc of the swing arm.  The tightest point of the chain is when the axle, swing arm pivot point, and sprockets are in a straight line.  Now, Yamaha has there chain slack spec listed for a partially loaded suspension.  A partially loaded suspension will be closer to the tightest chain straight line condition when compared to a completely unloaded suspension.  As a result I think if you were going to set slack with an unloaded suspension, the spec would be greater (i.e. more slack). 

 

Edit - so I though about this more and I may be wrong here.  The anti-squat geometry may impact how this works.

Edited March 9, 2021 by AngryNeutron

[Alain2]

4 hours ago, AngryNeutron said:

Sorry, but I don't agree.  An unloaded suspension is one that does not have any weight on it, including the weight of the bike.  To unload you need to suspend the rear wheel off the ground which isn't really practical on the side stand.  This goes to my original (albeit vague and sarcastic) point.  Yamaha engineers specified the chain slack specification with the suspension loaded (i.e. on the side stand) so that's how it should be checked imo.  The slack setting for a properly unloaded suspension will be different than what is listed in the manual.

My bike is stock and stay unloaded on the side stand if I lift the tail, it does have a sag on its own, but I make sure the sag is at minimum. Load on the suspension varies from one bike to another one depending on suspension set up and equipment.  You guys are all running different chain slack because you are adjusting at various sag. If your setup as a lot of sag, you run your chain with more slack than you need.

[mpatch]

The best way is to pull a bolt out of the rear shock when on a stand and check. 
Make a note of the measurement and you’re set. 
Or if you have a fat friend then can sit on the back of the seat or you can also use a ratchet strap.

On smaller bikes you can do the reverse Superman and do it also. 

[ADVUSA]

On 2/8/2021 at 3:09 PM, ja7455 said:

Here is my version of chain adjustment. It's just my opinion and is not the only way or the best way just what I have found to be simple and quick. 

The recommended adjustment is 43-48 mm at the center of the chain (between sprockets). The distance is between the chain guide and the top of the chain, when pulled down. I made a simple tool for measuring this distance using a piece of scrap plastic (you can use most any material you have laying around). It is tapered from 40mm to 50mm with a line drawn at the 45mm mark. In the center of the adjustment range. Just slide the tool between the chain and the chain guide till it is snug. If the chain is loose it will go past the designated mark. If it is too tight it won't advance to the desired mark. Adjust accordingly. 

Since the tool kit does not come with an axle wrench for use in the field I made my own using a 1- 1/16" (same as 27mm) box end wrench from Home Depot ($12.50). I cut off the open end to save space and weight. Not necessary though. 

Hope this helps someone. 

ja

Thanks very much!  I made one of those short wrenches!

[ADVUSA]

Anyone know off hand the size of the chain adjustment bolt and nut size?

I don't see it briefly in either the service or owners manual...

[ADVUSA]

1 hour ago, ADVUSA said:

Anyone know off hand the size of the chain adjustment bolt and nut size?

I don't see it briefly in either the service or owners manual...

 

10 and 12mm  someone answered on another forum!

[papab]

On 3/9/2021 at 2:59 PM, mpatch said:

The best way is to pull a bolt out of the rear shock when on a stand and check. 
Make a note of the measurement and you’re set. 
Or if you have a fat friend then can sit on the back of the seat or you can also use a ratchet strap.

On smaller bikes you can do the reverse Superman and do it also. 

Has anyone done this and compared to the OEM method?   I'm too lazy to take a bolt out & I don't have any fat neighbors.  On my WRR I could superman it down.  The ratchet strap method makes me nervous, that seems like a lot of load on the rear frame, but I suppose it's the same as a really big  guy sitting on it.   It seems like this bike needs a lot of compression to line up the sprockets and pivot.

[JohnnieBoy]

...Or just put on the side stand like the manual says (1.) and adjust to desired point within spec +/-   Its not rocket science.

[rumrum]

I have just found out today that I have been riding around with my chain waaaay too tight. I thought it was within manufacturers specs at 43mm but after playing around and fitting a set of lowering links I found the chain was now under tension with the lowering links fitted. After consulting the workshop manual I noted the 43-48 mm is measured from the chain guide to the centre of the chain and not the swing arm as I had assumed. luckily have not done too many km since it was adjusted last. All sorted now.

[Mapbook]

I set the slack as per the book but i use a wheel chock to roll the front wheel in that holds the bike upright and keeps the suspension loaded.

Thanks to ja7455 good idea i set to 50mm i like a bit of slack it makes life easier on the gearbox sprocket.   

 

 

 

 

 

[JayD]

Can anyone tell me if a chain guide will alter the measurment of the chain slack?

[rumrum]

22 hours ago, JayD said:

Can anyone tell me if a chain guide will alter the measurment of the chain slack?

From the manual the 43 - 48 mm is measured between the back of the plastic chain slider ( which is located at the front of the swing arm) to the centre of the chain. I originally did not read the instructions correctly and measured 43 mm from the swing arm. this is a 6mm difference and as i found out by chance is waaay too tight when the suspension compresses. If you re meaning the chain guide near the rear sprocket, no that should not make any difference. 

[JayD]

@rumrumThanks, yeah, its supposed to be mesured from that rubber lip.

 

I was talking about a chain guide that you bolt on, I have the Acerbis one. It seemed to me that mine was keeping the chain up just sligthly, but taking of that small plastic piece that the chain slides against to measure didnt take me much time. Thanks for the reply!

[REDHORSECA]

My chain guide doesn't alter the slack measurement.