Chain slack - 750

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Chain slack - 750

Postby Freddy » 15 Nov 2018, 00:49

Just finished watching a series of suspension videos presented by the owner of Traxxion Dynaamic. Well worth watching. Anyhow, one of the series of 20 videos (all on the internet) covers 'other things'. One of these is chain slack, and how an over tight chain can affect rear shock performance.

What the presented says is to get someone as heavy as possible to sit backward on the bike, reach down to grab the wheel, and then bear hug the bike down as low as possible in its suspension stroke. Then check the chain slack in this highly compressed suspension state.

So I go out and try it (had to do it single handed) on my 750, with a chain correctly set to the 40?mm chain slack stated in the workshop manual. Guess what, tight as a drum when the suspension is near fully compressed.

From now on will be setting the chain much looser than recommended, and setting and checking with the suspension as fully compressed as possible.
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Re: Chain slack - 750

Postby Swampy » 16 Nov 2018, 18:09

On my 1100 the slack is as per pic, I have done it to that spec and I have had so many people say to me that it was too slack :o
I very very rarely carry anyone on the back so I think that i'll just stick with what I have :?
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Re: Chain slack - 750

Postby Freddy » 16 Nov 2018, 20:21

Over the years I'd seen a number of people with various model bikes say they even use a ratchet strap to near fully compress the suspension to check and set chain slack. I used to think it odd, but no longer. That's the way I'll be doing it from now on.

The very reason for 'chain slack' is so its not tight at any point in the suspension travel. If it gets tight at any point there isn't enough slack. Just hitting a half decent sharp hump in the road at speed should near fully compress the rear suspension.
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Re: Chain slack - 750

Postby Corey » 16 Nov 2018, 20:58

I also think chain technology has changed over the years, but chain slack, regular maintenance, and alignment, will make it last.

Motion Pro just came out with a chain slack tool, but I haven't used it.
https://www.motionpro.com/product/08-0674

I came across this very cool chain alignment tool years ago, and have been using it for years.

https://www.ebay.com/p/Profi-SE-Cat-Mot ... 624&chn=ps

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Re: Chain slack - 750

Postby ZR468 » 18 Nov 2018, 01:24

I was talking to the owner of the shop where I fix my bikes about chain slack only a fews weeks ago. He said the you only compress the suspension to adjust the chain slack on dirt bikes and off road bikes. For street bikes, you just adjust the chain with the bike on its centre stand. Reason being, dirt and off road bikes have much more suspension travel eg, 10 or more inches, most street bikes supension only have 4 to 5" of travel.
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Re: Chain slack - 750

Postby Corey » 18 Nov 2018, 04:29

I have removed my center stand years ago, and with a 4-1 aftermarket exhaust, use a Pit Bull Rear Stand to clean and adjust my chain. I agree, the suspension movement on our streetbikes is not a much as any off-road bike.
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Re: Chain slack - 750

Postby Freddy » 18 Nov 2018, 07:48

Doesn't matter how much rear suspension travel a street bike has. The sole purpose of 'chain slack' is to ensure the chain doesn't go tight at any point of the full suspension travel (whatever that is). If it does, there isn't enough 'slack' in the chain.

If people don't care if the chain goes tight as the suspension moves up and down, shortening the life of the chain, sprockets, and gearbox bearings, and contributing to a harsh ride and reduced handling by 'choking' the action of the rear suspension, by all means feel free to leave it that way.
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