Author Topic: A50/65 Primary Chain Tension  (Read 379 times)

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AdrianS

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A50/65 Primary Chain Tension
« on: 08 April, 2020, 06:34:19 »
Following on from my previous thread re a few questions about an A50, I set about looking at the primary chain tension.

Mine is an early A50 and the inspection covers are next to each other on the cover so couldnt reach the chain to check the tension..
I took the cover off and the chain appeared quite slack. I could push the tensioner plate up and down by about 1/4 inch.

So, how tight should the chain be? The manual says 1/8 inch up and down play on the top run. Is this 1/8 inch slack say if a straight edge is placed on top of the chain or is it 1/8 inch up and down movement when grabbing the chain with fingers. When set at that the chain seems quite tight as its easy to move the chain up and down 1/8 inch even when very tight! Does the chain get looser when the engine has warmed up?

DAVE BRADY

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Re: A50/65 Primary Chain Tension
« Reply #1 on: 08 April, 2020, 07:45:23 »
Good morning Adrian,

I always do mine cold as when hot it means a burnt finger trying to check the tension and I think the 1/8" to 1/4" is total up and down and not an 1/8th to 1/4" up and down as well.  The instructions for rear chain tension describe it better.

Dave.

AdrianS

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Re: A50/65 Primary Chain Tension
« Reply #2 on: 08 April, 2020, 08:44:31 »
My query was was this “loose” up and down movement or movement under a bit of pressure. It seems to be a matter of individual perception but I suppose it’s better to have it too loose than too tight!

DAVE BRADY

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Re: A50/65 Primary Chain Tension
« Reply #3 on: 08 April, 2020, 09:30:21 »
Yes, a bit subjective and it will vary if the primary cover is off or if pocking a finger through the inspection hole as on later cases.   The way I do it through the inspection hole is 'can I actually move it up and down a bit?', which seems to work.  So with the cover off I would say movement under a bit of pressure.
Perhaps the feel of the clutch can also be an indicator of too tight a chain.  Although other things can cause clutch issues, with the lever pulled in does the centre turn smoothly or is it tight on the bearings?
It would be great if we could attach a spring balance (fishing type) and measure the ideal deflection by effort exerted then we could get a better idea of what it feels like.
 
Dave.

AdrianS

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Re: A50/65 Primary Chain Tension
« Reply #4 on: 08 April, 2020, 10:10:55 »
Cheers Dave