How to check chain tension?

Discussion in 'General VFR Discussions' started by jaimev34, Sep 28, 2008.

  1. Rsparky

    Rsparky New Member

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    Ok, I did my search. Thread revival time.

    I am in dismay that a manufacturer can include a centerstand, but have you check tension off it. Now I miss my conventional swing arm... Say I find the tight spot. Get it to spec. (which, btw, really only 1"? I expected more like 35mm) then put it on the centerstand and pull it down, measuring the total distance from the guard. Record for posterity.
     
  2. djenkins

    djenkins New Member

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    Truly, this thread has staying power...

    I'm going to attempt to insert a picture of my 2007's chain deflected up from below the swingarm. This is a point just rearward of what I believe to be the center of the chain. As you can see (if I'm successful with inserting the picture) the chain is stopped by the rubber guard on the bottom of the swingarm. The distance from the top of the chain at rest to intersection with the swingarm guard is 18 mm. This is less than the minimum recommended chain slack of 25 mm--so to be within spec, the chain must have additional slack from this point.

    My question is, once the chain reaches the swingarm guard and cannot deflect up any further at that point, aren't I then measuring the remaining slack between the point of contact with the swingarm and the front sprocket, and not between the front and rear sprockets? So I get a hybrid measurement, partly from rest to contact with the swingarm guard (18 mm), and then from contact to maximum deflection (an additional 12 mm in my case), measured from the point in the photo from where I've marked the chain with 2 blue lines, which I'm judging to be the mid-point between the sprockets. It's not really an accurate measurement of the chain slack measured between the front and rear sprockets. Very frustrating.

    Meanwhile the bike shifts and rides great and I never notice anything that sounds like chain slapping against the swingarm.

    Am I safe to simply measure the chain slack at the mid-point, allowing the chain to run into the swingarm guard, continue pressing upward until it stops, and take that distance as an accurate measurement of the chain's slack?

    20161016_144239.jpg
     
  3. Rsparky

    Rsparky New Member

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    Your measurement of 18 is more like 36. Gotta pull down on it too.
     
  4. djenkins

    djenkins New Member

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    Thanks for pointing this out.

    Pulling down on the chain deflects it minimally, only 1-2 mm. So total slack to the point where it hits the swingarm guard is 20 mm.

    If it had excessive slack, would it pull down more?
     
  5. mark641

    mark641 New Member

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    Hi, yeah of course. An unfitted chain will turn round on itself.
    Pull down on the chain , place a rule at half way point, push up and measure the deflection.
    I think you're over thinking the whole thing. Go slightly more slack than over tight as over tight puts mucho strain on transmission.
     
  6. rckrzy1

    rckrzy1 New Member

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    I find on this bike the chain should just touch the bottom of the chain guide and that's about 25-30mm slack. And like most say better a little loose . And you young guys don't remember non o ring chains you have no idea how bad they wore. I had a 82 Suzuki gt750 with a 630 chain, it weighed about 50 pounds. It was huge and it would let you know it was loose when it would drag center stand on throttle off.
     
  7. VFRIRL

    VFRIRL New Member

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    Are you better to have the 1 inch slack when sitting on the bike with the suspension sag compressed? I done this today, it seems a lot looser than that when the bike is on the centre stand, I'm a fairly big guy so I think the extra slack is called for.
    also trying to figure if it's time to change the chain and sprockets by looking at that red zone alignment marker on the swingarm, bit hard to be sure going by that, seems to be ok on the rear sprocket at 20k miles now, original chain and sprockets on this bike. amazing 21 years old, old enough to drink!!
     
  8. James Bond

    James Bond Member

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    Just push up on the bottom of the chain and as long as it isn't grossly loose, leave it alone. Watch how loose Moto GP bike chains are run.
     
  9. VFRIRL

    VFRIRL New Member

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    I've never noticed the chains on moto gp bikes.
     
  10. squirrelman

    squirrelman Member

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    20k is just about the average life of an OEM chain and sprockets.
     
  11. VFRIRL

    VFRIRL New Member

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    I suppose it all depends on how the chain has been maintained, cleaned,lubed, correct tension, and the conditions the bike has been used in.
     
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  12. James Bond

    James Bond Member

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    I think that pretty much sums it up.
     
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  13. James Bond

    James Bond Member

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    Just thought of something I do now and then. Spray your chain with GT85, let it dry, then use it as a cleaner lube for short time slots.
    GT85 can be had on Amazon, is from the UK I think, and is amazing stuff. It cleans well, dries quickly and leaves a nice thin coating of PTFE (Teflon) on whatever it is on. It's good for some gun actions too. A lot of things are over-lubed IMHO. A clean chain (or gun) is a happy chain. I don't like Chain Wax because of the amount of dirt and sand it attracts and holds onto quickly. I like thinner lubes. Just another philosophy that has brought me good results.
     
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  14. VFRIRL

    VFRIRL New Member

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    GT85 is readily available here and cheaper than WD40, I always thought it was inferior for that reason, I will try it out, I usually clean with kerosene and blow the excess off with an airline, then lube with 80/90 gear oil but I don't over do it, I hate that chain wax, if you ever remove the front sprocket cover from a bike that's been lubed with chain wax you'll see how much dirt and grit it gathers, perfect grinding paste.
     
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  15. James Bond

    James Bond Member

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    Ditto Chain Wax. GT 85 is a much more superior and useful product than WD 40 IMO. GT85 displaces water too and is a great penetrant.....i.e. motorcycle chains now and then. I mostly use differential gear oil like Honda recommends. It's cheap, clean, and works.
     
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