Chain tension ???

[lrm74]

My BB was running fine - chain nice and loose ( two-up mostly and shock spacer fitted) - then fitted some Jaws Risers and new tyres a few weeks ago ready for our trip to France. Checked the chain and it seemed to have plenty of slack after the type change. Then after a couple of rides out I checked the chain just before the trip and thought it was not that slack, but had a good inch of movement - so off we went this week on the ferry to France. At the last fuel stop I did not put my earplugs in - and had a shock at the amount of noise coming up from under the fairing ! Sounded like a mixture of loud whining noise and echoing sounds. Every time I slowed right down and changed gears etc - it sounded rough as hell.
Next day I wondered if it would b e better without the loaded top-box and panniers fitted - but the bike still sounded "wrong". Revved the engine and it sounded ok - so I realised it was something to do with gearbox, clutch, or drive chain ? Took it very easy on way home and now need to get out there and see what is going on ??
I am starting to think that the BB is probably very sensitive to CHAIN TENSION ? I know a tight chain can cause gearbox bearing problems but it really was not that tight ? I will go out and loosen the chain tomorrow but can anyone advise if this is a common problem with the BB ? My old VFR800 preferred a loose chain and I wonder if this is an important factor on the BB - or is my chain and sprockets just sh*gged ??
(Note - spinning rear wheel on centre stand sounds pretty quiet and non-lumpy so I has assume the chain was ok (and scottoiler is fitted).
Any ideas guys ?? Cheers

 

[ambo478]

I just fitted the best chain and sprockets i could get my hands on (DID extreme) and Im not happy with some of the noises I hear either.
Despite the fact I have lined them up several times using various methods (laser and the steel rule ) I still expected such an expensive item to make less noise.
Now bought new cush drive rubbers maybe this will help.

 

[Centaur]

Just a thought...

Are you checking the slack with normal weight on the bike or just on the centre stand?

 

[Flymo01]

Are you checking the slack with normal weight on the bike or just on the centre stand?

Just wondering, with the 'bird, which is the correct method?

 

[Wolfie]

Just wondering, with the 'bird, which is the correct method?

side stand according to the workshop manual. 30mm of slack

 

[CBRDEAN0]

side stand according to the workshop manual. 30mm of slack

Should there not be a little more slack if the bike has a shock spacer on ?

 

[troubleshooter]

Should there not be a little more slack if the bike has a shock spacer on ?

Definitely:yo:h1t1t

 

[Wolfie]

Should there not be a little more slack if the bike has a shock spacer on ?

manual says inch to inch and quarter i believe.


as to fitting a spacer why should there be more slack?

 

[troubleshooter]

manual says inch to inch and quarter i believe.


as to fitting a spacer why should there be more slack?

because the distance between the sprockets changes, if you don't leave it a bit slacker than the manual says, it overtightens the chain when the swinging arm straightens out. Its one of those things that happens when you bugger about with the manufacturers settings with the result that the tolerances in the manual no longer apply.

 

[Jaws]

manual says inch to inch and quarter i believe.


as to fitting a spacer why should there be more slack?

Because it changes the angle of the swing arm.. takes it past apogee so to speak

Chain MUST be adjusted with someone sitting on the bike if a spacer fitted, other wise it will end up like a bow sting and wreck the output shaft bearing ( and possibly the sprocket carrier )

 

[Wolfie]

because the distance between the sprockets changes, if you don't leave it a bit slacker than the manual says, it overtightens the chain when the swinging arm straightens out. Its one of those things that happens when you bugger about with the manufacturers settings with the result that the tolerances in the manual no longer apply.

when bike is on sidestand the wheels are not pushed into the ground anymore than normal, the spacer raises the seat height.

Now when you sit on the bike there is more weight which compresses the spring by 25mm roughly for the sag you have set, the linkages move and the wheels are again brought into line with what thy normally are without spacer.

hence the distance between sprockets stay the same.

now if you are one of those who set the chain when bike is on the main stand then yes maybe the pivoting action does indeed bring the sprockets closer. but then you are setting the chain up wrong and deserve all you get.:-0)

I will come clean here, bike on main stand does indeed result in an over tighten chain. Also if chain is set whilst on side stand then when on main stand it looks to loose.

set on side stand at 30mm and mine is fine.

unless off course she gets on the back then i need to adjust the rear suspension and chain for the extra weight. otherwise i can hear the chain rumbling and grating because it is too tight.

 

[Wolfie]

Because it changes the angle of the swing arm.. takes it past apogee so to speak

Chain MUST be adjusted with someone sitting on the bike if a spacer fitted, other wise it will end up like a bow sting and wreck the output shaft bearing ( and possibly the sprocket carrier )

wheels cant get closer if they are on the ground. the spring is not man enough, if it was you would not have any bike sag.

Yes having the rider sitting on the bike and then getting somebody to adjust it could be th way, but to what figure , the one that the rider took before spacer was fitted?/ that is a lot of feckin about, and to be honest would you trust somebody else to adjust your chain for you?? i wouldnt and if i was sitting on the bike i couldnt check they had done it to my standards or measurements.

 

[lrm74]

Cheers for the responses.
I apologise now if this is a stupid question but I have always wondered how a chain reacts on the sprockets in real terms ? i.e. When the front cog starts to turn (based on engine power) the cog will PULL hard on the chain "top section" - running to the rear cog - and hence I would expect the "lower section" of chain (rear cog back to front cog) to loosen slightly ? On the same level I was also wondering if it is possible to set the back wheel in a position which accentuates the "tightness of the top section" ? ie to put this in extreme - say you had an over-length chain and fitted it at the outset so that the top run was about right, but the lower run had an extra link or two ? I assume that once the wheel is locked in place the set-up would not allow the chain to "right itself" ? So you would have a big sag in the lower chain run ?
So am I right in thinking that the correct way to fit the back wheel and chain should be to always start by pulling the wheel BACK as far as possible to fully lengthen both the top and bottom chain run equally - before gradually pushing it back to the right slackness - and so keeping both chain lengths equal ????
I might not have explained that very well - but I am sure you geezers will soon put me right ???

 

[CBRDEAN0]

Cheers for the responses.
I apologise now if this is a stupid question but I have always wondered how a chain reacts on the sprockets in real terms ? i.e. When the front cog starts to turn (based on engine power) the cog will PULL hard on the chain "top section" - running to the rear cog - and hence I would expect the "lower section" of chain (rear cog back to front cog) to loosen slightly ? On the same level I was also wondering if it is possible to set the back wheel in a position which accentuates the "tightness of the top section" ? ie to put this in extreme - say you had an over-length chain and fitted it at the outset so that the top run was about right, but the lower run had an extra link or two ? I assume that once the wheel is locked in place the set-up would not allow the chain to "right itself" ? So you would have a big sag in the lower chain run ?
So am I right in thinking that the correct way to fit the back wheel and chain should be to always start by pulling the wheel BACK as far as possible to fully lengthen both the top and bottom chain run equally - before gradually pushing it back to the right slackness - and so keeping both chain lengths equal ????
I might not have explained that very well - but I am sure you geezers will soon put me right ???

If the bike is in neutral when you do the chain tension the front sprocket will rotate slightly and tension the top chain run as you check the slack on the bottom run.
Therefore you only need be concerned with the lower run slack.

 

[lrm74]

BTW - I just checked the small bike handbook on the subject of chain tension setting, and it actually states to put the bike on the CENTRE STAND ?
John said that with a spacer fitted you must have somebody sat on the bike but I am not sure if that means "30mm slack with somebody on the bike" or what, as that sounds too slack ?

I also noted the perameters stated are 25mm to 35mm and that over 40mm slack can result in damage to the frame ?

So I am going to try setting at "just over" 35mm on the centre stand - and see how that goes.. ?

 

[Jaws]

If you do that with a spacer you are about to cause some bloody serious damage.. end of

You set it to the normal amount ( 30mm ) but with someone sitting on the bike

Ultimately it is up to you, but just do me a favour.. Adjust it on the centre stand and then with you sitting on it ask someone to check it.

Then you can believe your own findings d34l

 

[jono49]

"Real Men" ride without the spacer! :yo: Woosies, Woofters, Faggots, Fudge packers, and "Bankers" Fit a spacer as they haven't the strength to man handle the "Bird" p0pc0rn41

 

[Centaur]

6mm spacer. 18 stone rider.

Local birder recently asked me to look at his chain as it was making a funny noise. He had cleaned then adjusted it on the centre stand. It had no slack on side stand and was bar tight with him sitting on it. Slackened to 30mm on side stand. Still no slack with him sitting on it. Readjusted it on side stand until it couldn't quite reach the arm rubber and that left a little slack with him sitting on it. There were no tight spots so left it at that. Chains.......feckin minefield since I started riding.

 

[gypsy]

Chains are so last year :-0)

 

[silverfox.xx]

Chains are so last year :-0)

Your's push rod valves then :-0)


Bill, yes I set mine so it actually touches the under rubber guide, 7mm over length shock, use to do the same on 6mm spacer. 35/45 mm slack.