Chain Tension

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simon.holyfield
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Chain Tension

Postby simon.holyfield » Sun Nov 17, 2019 12:07 pm

Reading the various owners guides in my library, I noticed Ariel specify "3/8" up and down movement" for primary chain tension.

Now, if I read this as +3/*"/-3/8", I end up with a very loose chain. If I set my chain to 3/8" movement between the uppermost point of stretch and the lowest, so +3/16"/-3/16", it is very tight.

I have it set somewhere is between which feels OK to me. What do you all do?
cheers

Simes

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Mick D
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Re: Chain Tension

Postby Mick D » Sun Nov 17, 2019 1:06 pm

Hi

I've set mine to 3/8" total play with the chain / sprockets assy set at it's 'tightest' position. Not run it yet but seems fine to me.

Regards Mick

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markus.nikot
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Re: Chain Tension

Postby markus.nikot » Sun Nov 17, 2019 2:16 pm

On my bikes I adjust it quite tight but check always in different positions cause of the clutch wobble.
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dave.owen
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Re: Chain Tension

Postby dave.owen » Sun Nov 17, 2019 2:33 pm

I set at 1/2$ total movement.

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Simon.Gardiner
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Re: Chain Tension

Postby Simon.Gardiner » Sun Nov 17, 2019 6:19 pm

I've always set to 3/8" but I only use gentle pressure to find the 'extremities'.
(That's my half-dollar worth ! :D )

SG
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Re: Chain Tension

Postby Ian.Taylor » Sun Nov 17, 2019 6:47 pm

I insert my finger under the chain and lift up.If it goes close to 3/8 it's good.
I do the rear chain this way as well.
I was taught to take measurement from rest position to full movement Re 3/8 ,up or down whichever is your preference

john.whiting
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Re: Chain Tension

Postby john.whiting » Sun Nov 17, 2019 9:49 pm

Primary chains often wear in spots.....so be sure to check for excessive tightness for several complete rotations of the chain.....Ive found the worst wear situation is if the chain is a multiple of the engine sprocket.

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alan.moore
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Re: Chain Tension

Postby alan.moore » Mon Nov 18, 2019 6:17 pm

As Mick, 3/8" total at the tightest spot. With one finger push lightly down till chain is taught (not bar tight) then using just enough finger pressure push upwards to get the chain taught.

Not wanting to teach Grandmother to suck eggs but...
Also a good idea to check the condition of the lower gearbox pivot bolt hole. If the bike has been used with this bolt slightly loose the hole can 'oval'. Result is that you set the primary tension, tighten the top and bottom gearbox bolts up and then after a ride find the primary chain is bar tight. This is because the pulling force of the rear chain has pulled the bottom of the gearbox backwards along the ovaled hole. Drilling out the case slightly and fitting a piece of thin wall steel tube sorts that out.

Another point is the top adjuster. If you overtighten the primary then it's normal to wind the adjusting nut backwards a bit to give a little slack, then tighten up top and bottom through bolts. You should then nip up (screw in) the adjusting nut against the bracket. This stops the gearbox being pulled forwards by the force of the primary chain and slackening the chain. A small movement in the gearbox can make a big difference to chain tension.

Oh and always check rear chain tension afterwards and don't try and adjust primary with a tight rear chain.

Cheers
Alan
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