chain slack

[the Ferret]

When I started riding motorcycles in the mid 60's we learned how to adjust a chain by finding any tight spot in chain, putting it in the middle of the lower run, then push up on the chain to measure slack.

In fact when I wrote the "How To adjust the chain on your CB 1100" for that section of the forum 6 years ago, that is how I advised doing it.

http://www.cb1100forum.com/forum/showthread.php?tid=7158

I've never seen a factory trained mechanic do anything other than push up from the lower run to gauge chain tension.

It seems now the procedure calls for starting out the same way but instead of pushing up to measure slack, now it seems they want you to pull DOWN first, then measure slack up from there. On a chain like the CB's which calls for 1"-1.4" that could make a heck of a difference in tautness.

I know chain tension isn't "critical" and we've always believe "a loose chain is happier than a tight chain", but was wondering which procedure you guys are using, and if any of you have tried to measure the difference using both methods?

something new to discuss.

 

[dave]

When I started riding motorcycles in the mid 60's we learned how to adjust a chain by finding any tight spot in chain, putting it in the middle of the lower run, then push up on the chain to measure slack.

In fact when I wrote the "How To adjust the chain on your CB 1100" for that section of the forum 6 years ago, that is how I advised doing it.

http://www.cb1100forum.com/forum/showthread.php?tid=7158

I've never seen a factory trained mechanic do anything other than push up from the lower run to gauge chain tension.

It seems now the procedure calls for starting out the same way but instead of pushing up to measure slack, now it seems they want you to pull DOWN first, then measure slack up from there. On a chain like the CB's which calls for 1"-1.4" that could make a heck of a difference in tautness.

I know chain tension isn't "critical" and we've always believe "a loose chain is happier than a tight chain", but was wondering which procedure you guys are using, and if any of you have tried to measure the difference using both methods?

something new to discuss.

Chain slack means the total up and down movement "free play" of the chain. This total movement should be measured with only a very small force applied to the chain during the measurement. Chain tension is critical. A too tight chain will cause the countershaft to break off at the engine case - I know this from experience.

 

[Jfro5687_imp]

I have always done the pull down and push up-to measure the full slack TBH. It was only reading this very forum that I thought maybe I was doing it wrong? I always figured there’s only a certain amount of slack in a chain so you should get the top chain run taut by doing this. The manual doesn’t seem to be 100% crystal clear. Where did you get the update from ferret?

 

[the Ferret]

Well the pic on the swingarm for one and YouTube vids of course. If you pull down it takes out slack along the upper run and if you push up it takes out slack of the upper run. Seems to me, you'd only need to take the slack out once by pushing up, but I'm old and sometimes what we learned 60 years ago isn't necessarily what is thought of as proper procedure today. Just trying to learn.

 

[rickcb]

Well the pic on the swingarm for one and YouTube vids of course. If you pull down it takes out slack along the upper run and if you push up it takes out slack of the upper run. Seems to me, you'd only need to take the slack out once by pushing up, but I'm old and sometimes what we learned 60 years ago isn't necessarily what is thought of as proper procedure today. Just trying to learn.

I've seen Yamaha owner's manuals that called for a measurement where you pulled down and then measured up. I assumed Honda's were the same and used that strategy on Jennifer's first CBR500R. The chain didn't even last 10K miles. It was *way* too tight when measured that way. I'm pretty sure Honda's are a push-up only measurement. That's what I've been doing.

 

[mvk24_imp]

I have always gone to the middle of the bottom of the chain.

Put a ruler or tape measure behind it. And give it a gentle wiggle both Up & Down and make sure it falls within the margin.

If it would move 1 inch upwards from baseline, then it would also move 1 inch below baseline (downwards). And that would give you a total slack of 2 inches instead of 1 inch in 1 direction.

This is the way I learned (but it can be wrong and im open to hearing otherwise)

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[the Ferret]

2 inches would be a ton of slack in s CB chain. Spec calls for 1 inch to 1.4 inches.

 

[GoldOxide_imp]

Da. Two inches sounds maybe more for a dirt bike chain.

 

[mvk24_imp]

2 inches would be a ton of slack in s CB chain. Spec calls for 1 inch to 1.4 inches.

O no I know. I was using even numbers as an example

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[the Ferret]

2 inches would be a ton of slack in s CB chain. Spec calls for 1 inch to 1.4 inches.

O no I know. I was using even numbers as an example

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O no I know. I was using even numbers as an example

Sent from my SM-G965U1 using Tapatalk

oh, ok, gotcha

 

[spechg]

This is the diagram in the owners manual. Looks to me like the measurement is from the chain at rest to its position when pushed upwards. The measurement should be between 25mm and 35mm.

 

[the Ferret]

That's how I always learned to do it, but I think the sticker on the swingarm says differently and to do it as shown in this video

Google Search

 

[Cormanus]

I have always gone to the middle of the bottom of the chain.

Put a ruler or tape measure behind it. And give it a gentle wiggle both Up & Down and make sure it falls within the margin.

If it would move 1 inch upwards from baseline, then it would also move 1 inch below baseline (downwards). And that would give you a total slack of 2 inches instead of 1 inch in 1 direction.

This is the way I learned (but it can be wrong and im open to hearing otherwise)

Sent from my SM-G965U1 using Tapatalk

Ive no argument with your technique, mvk, but surely the sheer weight of the chain will mean it will move further up than down? In other words, the lower run will be bow shaped at rest.

 

[Lord Popgun]

The service manual shows the horizontal line at the bottom of the lower chain and the upper line 1-1.4” up from it. The procedure says nothing about pulling down on the chain first. The picture would indicate that with the chain at rest, the lower edge should move no more than the 1.4”. But the pic above should give the same results. The tag on my bike shows what the service manual shows, but uses tiny arrows that are hard to see exactly.

It would seem to me that pulling it then pushing it is going to result in an adjustment that is too tight. However, do what you want.

 

[the Ferret]

someone with a 14 std please look (or take a pic of) at the decal on the swingarm for me. I swear I saw it with up and down but mine is hidden behind a beautiful symmetrical chrome pipe on the lh side. lol

 

[Lord Popgun]

Well Ferret, you probably did see it with up and down. That what mine shows, but not pulling it down then up.

Gotta ask. Why can’t you just go look at yours?

 

[the Ferret]

answered above, plus I'm old and have trouble getting down and back up lol

If yours shows up and down, how does it get up and down without pulling and pushing?

 

[GoldOxide_imp]

This is the diagram in the owners manual. Looks to me like the measurement is from the chain at rest to its position when pushed upwards. The measurement should be between 25mm and 35mm.

This looks okay to me. Gravity pulls it down, pinky pushes it up. What's the diff? And the answer you have.

 

[Lord Popgun]

Ferret, what Gold said.

 

[the Ferret]

Well Ferret, you probably did see it with up and down. That what mine shows, but not pulling it down then up.

Gotta ask. Why can’t you just go look at yours?

Did you watch the Ari Henning vid I linked?

BTW I'm perfectly happy doing it the way I've done it for 56 years, just curious if I've been doing it wrong for that long lol