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7 years and I still can't adjust my chain

5K views 48 replies 9 participants last post by  CB700S 
#1 · (Edited)
I have the same problem only worse on my CBR, 1/4" of free play on the right side of the axle that I can't get rid of.

- Loosen axle nut
- Left side of axle at the chain adjuster has no free play, set the tension from the left side.
- Right side moves back and fourth 1/4"
- Finger tighten the right adjuster counter-clockwise until it's snug. But then the wheel is out of alignment
- In order to loosen it, I have to turn the adjuster two revolutions clockwise nothing is happening before it starts to push the wheel towards front of the bike. I think this is where all the free play is but I don't understand why. If I go back out counter clockwise until it's snug I still have the 1/4" of free play.

I don't even know if the freeplay is my problem or not, all I know is 20 miles and it's loose and out of alignment time and time again.
 
#3 ·
To make sure it's aligned while tightening, use a rag between the chain and sprocket on the bottom side and roll the wheel forward to pull the axle tight to the adjusters. I hold tension while measuring the distance from back of the swingarm to the end of the adjuster with the depth gauge on vernier calipers.
I start with the right side in a bit too far. Hold tension with wheel and rag with my left hand and back out the right side adjuster and use vernier calipers with my right. Stop when you hit the number you're looking for. Keep holding the axle against the adjuster and swap the caliper for a torque wrench. Snug up the axle nut while continuing to hold... It should not have moved from your desired location. You can get it within a few thousands easily. Less, if you want.
As Islandboy said, opposite lock the adjusters with light but equal torque. Left, pull, counterclockwise- right, push, clockwise.
 
#4 ·
I did a LOT of work on my 919 this year. New chain/sprockets, 3 different sets of tires, clutch, front/rear brakes and I'm redoing the forks this week.

When I had the rear tire off, I noticed that the adjuster had enough room for a lock nut. A thin nut that would go on the thread where you see the threads as you adjust them. This and a thin washer could be torqued against the end of the swing arm once you find the right spot for the adjusters.

I didn't have the right nut for this, but either a single nut or double nut should do the trick. I think (haven't verified) that an open end wrench would still fit in there as this would be a small nut.

TBH, I don't know why they move, they don't seem to move much but several people have reported that it goes out of adjustment.

The nuts that I'm talking about would be about 1/2 the thickness of a standard nut and would need to have a good flat washer so as to not dig into the aluminum swing arm. If you look at the number of threads you have exposed, you should have enough to get a nut in there, maybe two thin ones to lock against each other. A hardened washer should keep the swing arm intact.
 
#5 ·
Something else I found that helps is make all your adjustments with some torque on the axle nut. Sort of holds everything in place, stops the freeplay slop.
As far as the alignment goes this is how I do it. Real simple.
I first set the correct chain slack and have the adjusters set equally on the marks. Then, by eye balling the chain running on the sprocket from the rear, I centre the sprocket. This is done as I'm spinning the wheel by hand and making small adjustments. It's often the most quiet spot too.
This is done with some torque on axle nut. To prevent axle slip if I need to reverse an adjuster bolt and take up the freeplay.
Once I'm happy I fully torque axle nut then set adjusters opposite lock.
Hope thats clear.
 
#6 ·
When I first got my 919 more than 10 years ago I had an issue that the chain would not stay adjusted. It made no difference how I torqued the axle nut or played with the adjusters. Then, when I first replaced the tires and took the rear axle shaft out I found an issue.
While I had been properly setting the chain free play and tightening the axle shaft nut, the nut and washer were bottoming on the axle shaft shoulder and not creating sufficient clamp load to hold the shaft in place. It would be snug but not properly clamped. All I needed to do was add a larger heavy washer next to the adjuster device. As you can see in the pic I now have about 2 threads extending beyond the nut.
I know all of our bikes are different and the tolerance stack-ups will vary widely but adding a washer for my situation helped keep everything tight and in place.
Good luck!
 

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#17 ·
There’s actually a simple if a bit awkward way to do this and it’s traditional for older Hondas that share this same chain adjuster system. It’s worked pretty well for me for about 20-odd years.

Push the wheel forward whilst adjusting.
 
#18 · (Edited)
While I haven't done anything to the adjusters past safety wiring them, I did come up with a way to positively lock them in place. Once the chain is adjusted simply hold the bolt and tighten the lock nut against the bracket. It precludes any change in the position of the adjuster by preventing the bolt from turning.
 

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#19 ·
That sounds like the same thing I came up with, except my idea has the lock nut on the inside of the bracket. I figured the bolt is the thing that is going to move, so a lock nut on it should do the trick. I just don't have the exact size/pitch or sourced the thin nut to do this with.
 
#22 ·
The bolt doesn't move. There is some freeplay. It's apparent when you switch from turning the bolt from in to out or vice versa.
After you have set your chain tension/alignment and set the axle nut torque, set the adjuster nuts to oppose one another and against the chain pull on the axle. If you have both adjusters set to pull then I find the axle can slip/take up that small amount of free play on the brake caliper side. This can loosen chain and throw off alignment.
 
#23 ·
Usually, when I am adjusting the chain I find the right adjuster bolt loose. Since I safety wire the bolt, the only other source of movement is the axle / adjuster. I took some measurements and crunched the numbers to quantify the actual angle the wheel deflects if the axle is moving until it contacts the circlip, in this case the space between the circlip and the adjuster body is 2mm. The angle is arctan 2mm divided by the distance from the center of the wheel to the outside of the swingarm, thus: arctan (2/140) = 0.818 degrees. Doesn't sound like much, does it? Run that angle forward 1460mm (wheelbase) and the offset from the steering axis is 19mm! That's noticable.

Okay, then what to do to stop this? How about inserting a 10mm washer just under 2mm thick between the adjuster and the circlip on the bolt? That would reduce the possible movement from 2mm to essentially zero, and costs less than a buck.

Digging into my very extensive hardware bench stock as soon as I post this.

Rob
 
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#24 ·
Hey Rob. I tried putting a washer behind the c-clip a couple of weeks ago. Didn't work. When I turned adjuster bolt in, so against the washer/c-clip the washer very quickly and easily pushed the c- clip off.
I'm just putting this out there but I don't think the c-clip is what pushes against the bracket. Maybe something is tapered and wedges internally?
 
#29 ·
Hey Rob. I tried putting a washer behind the c-clip a couple of weeks ago. Didn't work. When I turned adjuster bolt in, so against the washer/c-clip the washer very quickly and easily pushed the c- clip off.
That is not uncommon if a standard 10mm washer is used, as the I.D. is usually 10.6mm to 11mm. Excessive force applied to the face of the circlip cones it outward until it leaves the groove. The best solution is to use an 8mm washer that has been opened up to exactly the O.D. of the adjuster bolt, which is 9.91mm in diameter. The closer the fit, the less coning force is applied to the circlip.

An alternative to circlips are crimp clips, which are considerably stronger. They may need to be thinned to properly fit in the groove. See the sheet below.

The image is from McMaster-Carr, which also offers CAD files of most of their hardware, bearings, seals, and countless other small parts. I have literally hundreds of those files on hand, and it really makes designing assemblies much easier! Check it out.

Rob
 

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#26 ·
Eyeballing the components easily reveals the designers intent.
It's only intended to be able to apply significant forcing in one direction, as in moving the wheel rearward while the wheel is still clamped axially to some degree by the axle nut.
This is all evident by two thing:
1
There is only one thrust face on the adjuster bolt, and it only sees service when forcing the wheel rearward.
2
Forward forcing can only be under very light load, as it's reliant upon the circlip being a thrust surface.
In other words, only when the rear wheel is less than snug in the slots, with the axle nut backed off.

Keep in mind that the vast majority of the 919 fleet world wide, does not have centre stands nor race stands in their owners garage - IF they even have a garage.

Honda envisions a rear wheel that is weighted on a leaning bike, whose rear wheel is still aligned, that just needs some adjusting to compensate for some chain wear.
In this case, the adjuster design is A OK.

Personally, when it comes to positioning the rear wheel for proper chain adjustment, I feel that getting the wheel aligned first is the backbone of the job, done so with the chain loose, such that all subsequent adjusting movement is rearward.

Now to the circlip.
Most high volume circlips are designed to retain in one direction only.
Only one side is ground or stamped flat with no radius at the ID.
The other side will be radiused around the ID, and if that side sees thrust, the radius can too easily ride up on the groove and pop off. (Hence old school hot rod engines with floating piston pins would see back to back dual circlips at each end of the pin.)
It turns out my circlip pliers are at our son's, so I can't check mine but my assumption is that the 919's are low cost items with one side flat and one side radiused at the ID.
Make sure the flat side faces the hex headed end of the adjuster.
 
#34 ·
OK I see where your going. Could you fling the adjuster bolt. Instead use a same size bolt inserted into the bracket with a nut wound up to the correct distance on the inside as the spacer. A tack weld on that to hold it in place. Or even a lock nut. Square nuts?
Also since the actual bracket doesn't seem to force the c-clip off why not just pack out the inside with a washer instead. Remove the freeplay that way.
 
#35 · (Edited)
The replacement bolt with a thin nut inside the adjuster idea sounds like the best way to do this. The only addition i would recommend is a collar between the head of the bolt and the nut to prevent excess play. A couple of short pieces of heat shrink tubing would probably suffice, depending on the method of securing the nut.

The only problem there is it is difficult to find bolts of the length you will need that are fully threaded, which in this case is necessary. There is a work around: find metric allthread (threaded rod) and use two nuts fixed in place on each side of the adjuster frame by whatever method is applicable. JB Weld as an excellent thread locker.

Rob
 
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#38 ·
FWIW. On my bike when chain is lined up to run perfectly centered on the rear sprocket the chain adjuster marks on either side are not the same. If I adjust the bolts so these marks are lined up the chain runs against one side of the rear sprocket and I get a noticeable vibration in the left foot peg at about 5000rpm.
Also the difference between the two marks seems to get greater as the chain stretches with wear.
For me the right hand/brake side adjuster mark is further along. So axle is back further on right side. I think I got that right.
On another note I packed out the gap in the adjustment bolt from the inside with a washer. Much tighter now. Better.
 
#39 ·
What do you use to determine "perfectly centered"? I was thinking about one of those rods that attach to the chain and shows if it's lined up or not.

[ame]https://www.youtube.com/watch?v=CjJCLACcKWs[/ame]

How far off are your marks?

BTW, what was that bolt for in the above post?
 
#40 ·
I use my eye to centre chain.
I adjust until chain runs over sprocket with an equal distance between sprocket teeth and side plates of chain. So the centre of the sprocket tooth is on the centre of the chain roller. After alignment I spin the wheel by hand and make sure chain is centred. I do this by making sure I can push chain from each side an equal distance onto the sprocket. Basically making sure the sprocket teeth aren't hard up either side of the chain side plates.
My chain half worn the adjustment marks are now a half mark out. So left side is on 4 and right side is 4 and a half.
I was going to use that bolt to replace the stock adjuster bolt in an attempt to reduce the gap the stock bolt has. It was about 5mm too short. Besides a washer added to the inside of the stock adjuster bolt has removed most of the gap.
 
#45 ·
People still try to use the adjuster Mark's? Damn...

I put dimples in the center of rear axle bolt (both sides) and swing arm bolt (both sides). Then I use a large size $15 harbor freight caliper with the ends filed to tips so they automatically center in the dimples.

My process was: loosen axle bolt, adjust chain on both sides until sufficient slack obtained, kick rear tire inward, use caliper to ensure both sides are even, adjust as needed until even via caliper, kick tire and measure slack, then check if even with caliper, tighten up adjuster bolts, torque rear axle bolt to 55-59 ft lbs depending on look/feel of rear tire spin, double check chain is squared via caliper and done in less than 10 minutes. Had it down to an art.

The Tuono, that's a totally different animal and I haven't figured out a good process or method yet.
 
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