chain slack

[dave]

one poster mentioned breaking the countershaft... I find that hard to believe, would think the chain would snap first. I've seen several chains snap. anyway, that's my .o2 worth.
[/quote]
I broke a countershaft on my 1987 Honda CR500 because the chain was too tight - I think. I never figured out exactly why, but at the time I thought I had adjusted it properly. However, I may have either adjusted it incorrectly by not adjusting it at the "tight spot", or the non-stock sprockets I was using required greater chain slack. I purchased my 2002 Honda XR650L in boxes because the previous owner had stripped all the splines off the countershaft at the drive sprocket. He had taken it to a shop, where the bike was disassembled, but when he discovered how much it would cost to repair he decided to sell it to me. I'm not sure if improper chain tension had anything to do with this or not, but I discovered that when the chain was adjusted to the slack defined by Honda it became too tight when the swing arm was positioned where the distance between the centerlines of the drive sprocket and rear wheel sprocket were at their greatest. I am now running chain slack slightly larger than what Honda recommends. I have documented my chain slack experiment with photos that I am happy to share with this forum, but I don't really have the time to figure out how to post pictures. I am happy to email these photos to anyone on this forum, and maybe they can post them? Just PM me.

[Lord Popgun]

Cormanus, my Common Service Manual is not the latest edition. But the entry on chain adjustment matches what the CB service manual says. Except for checking slack on the top run on some models. No mention of pulling or pushing. Just check the slack at the midpoint. And has a picture with the arrows and lines.

[GoldOxide_imp]

I thought I knew how to adjust a chain until I read this thread. Now I’m just full of anxiety about whether I am measuring the right way. CB1100 for sale.

I wouldn't fault you for showing the spirit.

I'm about to just install a drive shaft after all of this lmao

Sent from my SM-G965U1 using Tapatalk

Awesome! I feel your power. Please do it. I really want to see it. A reason to come back to the CB1100. Honda will likely hire you.

[Stichill_imp]

btw... I have come up with a new chain maintenance product that works in one step. no longer do I have to clean and then lube... it's called break free clp! don't know why I never thought of it before. introduced to it in 1982 in the Marine Corps. so far it's working wonders!

Really? I have a ton of the stuff. Moot point though, have an automatic oiler on the way (if DHL doesn't screw up).

[max]

Having followed the thread with interest i did some experiment yesterday but decided that i wanted to know the measurements, so today i adjusted the chain according to the manual with the pull/push method of " best standard " and here are the results, hope i'm not boring anyone;

the difference between pushing and not pushing down on the centerstand


Chain adjusted to 33 mm play on centerstand ( virtually similar to sidestand in my case )


The shocks are removed, it's easier to remove the right one with the wheel elevated;


The wheel is lifted 105 mm off the ground which is the tightest position of the chain
and the slack is reduced by 8 mm ( now 25mm )


lifting the wheel to remove the shocks;


Five pics limit reached, on to part two;
Rather than using a tape measure i have resorted to pushing the chain up to the chain guide and found a point that corresponded with the correct slack of the chain, all i have to do is push the chain up, look at which point it meets with the plastic guide and know if the slack is correct;
too far forward means too tight, too far back means too loose.
The red dot is when the slack is according to the manual but like Dave i like a bit less tension for a more relaxed chain so i use the place of the blue dot,that also gives me a bit of slack just in case i forget to find the tightest spot in the chain, thus far it's working.....


here is what this place on the chain guide looks like from a distance;


Each to their own, just thought i would share my findings here and hope someone else will share his findings as well, always wanting to learn something new that i had not thought about, cheers.

[Cormanus]

Max, do I have it right: you removed the shocks before checking the slack? Then you checked it after first pulling the chain down?

To be clear—sometimes I take a while to understand these things—you put the bike on the centre stand and measured the gap between the swing arm and the chain (54mm). You then pushed the chain down and got a reading of 63mm. Is that right?

Did you check the actual slack from the resting (54mm) position and then from the 63mm position? If so, what was the difference?

I like your idea of having a spot on the chain guide that tells you immediately whether the chain is roughly in spec.

[Jfro5687_imp]

Excellent effort and write up. Learnt a lot there. The fact the chain tightens by 8mm due to swingarm movement is particularly important.

[michael1954]

Probably not a great answer, but I have been adjusting chains for a long time, and I just do it where it goes up and down about 1 inch or so, and have been doing this since I started riding. Have never broke a chain or anything else, but I do keep my chains clean and well lubricated all the time. I saw more chains fly off back in the day, dirt riding and flat tracking from guys with real loose chains, so mine are probably a little tighter than most people prefer.

[max]

Max, do I have it right: you removed the shocks before checking the slack? Then you checked it after first pulling the chain down?

To be clear—sometimes I take a while to understand these things—you put the bike on the centre stand and measured the gap between the swing arm and the chain (54mm). You then pushed the chain down and got a reading of 63mm. Is that right?

Did you check the actual slack from the resting (54mm) position and then from the 63mm position? If so, what was the difference?

I like your idea of having a spot on the chain guide that tells you immediately whether the chain is roughly in spec.

Sorry, i was incomplete, first check is with chain slack the way i usually like it, a bit loose ( 50 mm ) but it should be about the same as per spec, i just wanted to show what the difference between the two methods was in the first picture, the difference in the slack measurement is 63-54= 9 mm. so yes, you are right !

i then tightened the chain up per spec with the shocks as per normal, then i removed the shocks to measure how much tighter the chain would be if it was in line with both sprockets, that resulted in 8 mm less slack than spec, i.e. 25 mm between lower and upper position ( pushed/pulled ).

Just to be clear; the chain is not 8 mm shorter itself, the difference between lower and upper is reduced by 8 mm from 33 mm to 25 mm at the tightest position of the swingarm.

and last question; the slack of 50 mm (push/pull ) would have measured 41 mm ( just hanging down and pushing, not pulling ).
In the end it's just how you look at it but i have ruined a chain on the hornet 900 in quick succession by over tightening it, it was shot in 200 km, the chain on the cb1100 is now halfway the wear mark at 50.000 km.

Did the same with the cb1000r chain, found the correct spot on the plastic chain guide, push up to get the slack out of the chain in that spot where i put a small mark on the swingarm and it's done, very quick and always accurate.

Excellent effort and write up. Learnt a lot there. The fact the chain tightens by 8mm due to swingarm movement is particularly important.

That was the main reason i did the test, i have always wondered how much difference it would make, remembering that really big forces are at play when the chain is that tight so close to fulcrum ( a compound angle ) which will change with different bike designs, i actually thought it would be more than i measured, Honda did well with this one.

[Jfro5687_imp]

Thanks Max. So, just thinking out loud here (I’m clearly not going to do it). By Honda setting the limits as 1” to 1 1/4” in theory it only NEEDS to be 8mm (sorry for mixing measurements BTW) to allow sufficient slack in the drivetrain before it locks up.

In other words there is a decent safety margin built in here so unless you do your chain stupidly tight there should be no problems, at all.