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adjusting the chain question


Mike5100

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Mike5100

my chain slack done by the book is still within spec at 30mm, but I realised yesterday that whereas I thought I was pushing the chain upwards until its own tension stopped it, that's not the case, and the upper limit is dictated by it hitting some kind of plastic guide on the underside of the swingarm.  So I made sure the top side of the chain was tight (I think I rolled the bike backwards slightly), and this caused the bottom of the chain to sag further, meaning this time when I checked the travel it was 40mm.  

So what's the right way of doing it - top of chain tight, or relaxed?

Mike

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I'm new to this lark as well, so I've copied what it says from the manual:

 

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However, when I had my RK chain changed for the DID there was significant visible slack after about 2 weeks. I took the bike back to the dealer who stated that all chains stretch to some degree although the RK in 6000 miles didn't stretch half as much as the DID in 300....

 

Anyhow, the mechanic stated that the easiest way to check the correct slack was to see if you could make the chain slap against the underside of the swinging arm - not a consistent push/lift and touch (too loose) but a quick slap (if you couldn't slap it against the arm it was too tight.) And I watched the mechanic do this (as I was sat on the bike at the time.) No rolling forwards or backwards, no checking for tight points.

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Guest martroy

I would say the Honda handbook is correct BUT I would suggest checking it with somebody sitting on the bike because on some bikes the chain tension can vary considerably with swinging arm movement...guess it's due to the design of the frame and suspension...the NC700X has quite a long suspension travel so it's best to check it's not too tight with the normal load on the bike.

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I would say the Honda handbook is correct BUT I would suggest checking it with somebody sitting on the bike because on some bikes the chain tension can vary considerably with swinging arm movement...guess it's due to the design of the frame and suspension...the NC700X has quite a long suspension travel so it's best to check it's not too tight with the normal load on the bike.

The handbook is clear about the process - although it would be much easier if they actually had the sense to fit the centre stand as standard.

 

But the slack they specify with the bike on the stand is already calculated to allow for movement of the swinging arm. If you set the same amount slack with the suspension compressed you're likely to be setting too much slack on the chain. (Because the gearbox sprocket is not co-centric with the swing arm bushes the length of the chain run changes as the suspension moves)

 

When the manufacturers set their service specifications they are not just guessing. They usually err on the side of caution when they can - but chain tension is usually going to have to be a mid range setting between too tigh and too slack. Getting it wrong can have nasty consequences.

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I try to follow the manual and only measure it when the bike is on the sidestand and do it a second time having rolled the bike forward a bit. Don't push the chain hard, use one finger - it's important that the chain isn't too tight. If you're doing this job regularly then buy a 27mm socket and breaker bar (and torque wrench if you're feeling flush). The spanner in the toolkit is only really suitable for emergencies.

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scottiedoug

we all have to remember that chains get a tight spot, so it is important to test the chain at various points. I find the easiest way for me is to jack up the bike under the engine just enough to let the wheel move and check the chain to find its tight spot and then drop the bike back down to the side stand  then you adjust the chain at the tight spot. It is better to have a chain a wee bit slacker than too tight.

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Mike5100

OK guys ... but I don't see any answers to my conundrum.  Pushing the chain up from its low point causes it to hit the underside of the swing arm BEFORE it has chance to go tight, so despite the fact that distance is only 30mm, the true measurement is 40mm.

Mike

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