Head stock bearing adjustment

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Big Pete
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Joined: Wed Mar 21, 2018 5:11 pm
Location: Highland UK

Head stock bearing adjustment

Post by Big Pete »

Hi apologies if this has been covered but is there any specific way of adjusting the above? Ie front wheel of the ground, wheel off etc. There is no steering damper fitted 58 csr frame and forks. Can't seem to get rid of a small bit of play.
Thanks in advance.
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Mick D
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Location: Aberdeenshire

Re: Head stock bearing adjustment

Post by Mick D »

Hi

Adjust with the front wheel off of the ground, exercise the bearing full travel left and right a few times and adjust to just discernable play - take it for a ride and repeat the procedure.

You should always feel the slightest play when pulling / pushing the front wheel, otherwise the bearing will be over tightened and degrade prematurely.

Regards Mick
Big Pete
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Joined: Wed Mar 21, 2018 5:11 pm
Location: Highland UK

Re: Head stock bearing adjustment

Post by Big Pete »

Good man Mick, thank you.
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StephenG80
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Re: Head stock bearing adjustment

Post by StephenG80 »

I presume the same amount of play should be the objective when a dampener is fitted ie on '54 model.?
SPRIDDLER
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Re: Head stock bearing adjustment

Post by SPRIDDLER »

It's in just about every one of dozens of workshop manuals in Christians Archive.

http://archives.jampot.dk/book/Workshop ... dition.pdf

Here's a pic from the manual above of how to place a bike on a box with front wheel off the ground.
Steering head adjustment.JPG
It'd be worthwhile spending time browsing the manuals in Christians Archive as they cover every maintenance task and answer just about every question ever asked ;)
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SPRIDDLER
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Re: Head stock bearing adjustment

Post by SPRIDDLER »

Do you know the history of your bike? Has someone rebuilt the forks/head stock?
Just a wild thought without knowledge of your bike's provenance...........
Inability to get the adjustment right could be due to having one too many balls in the head races. The correct number is one ball less than the number that will physically fit.
You 'can' fit 29 balls in each race but the correct number is 28.

See the manual, page 51 onwards re forks...

http://archives.jampot.dk/book/Owners_m ... ingles.pdf
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Which taken at the flood............'
SPRIDDLER
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Re: Head stock bearing adjustment

Post by SPRIDDLER »

Stephen G80 wrote:I presume the same amount of play should be the objective when a dampener is fitted ie on '54 model.?
Yes, but best to slacken it right off or it'll mask any play.
Last edited by SPRIDDLER on Wed May 16, 2018 7:26 pm, edited 1 time in total.
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REW
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Re: Head stock bearing adjustment

Post by REW »

Having done 2 sets of head races this spring, one AMC the other er, Honda, I would say if you take the front wheel off the bike you will find it easier to assess the degree of play - because you are not fighting the weight of the front wheel. Similarly turning the bars left to right will show any notchiness due to worn races or tightness if you have over tightened.

Remember also to set the initial tightness slightly loose then nip up the lock nut at the top. It is surprising how that final tightening can soak up play, particularly on a modern bike setup.

Also, don't forget to loosen the bottom yoke pinch bolts before you try to adjust the steering bearings or the job is impossible. And tighten them last too.

Finally, if you knew any or all of this, apologies!
Ron

1951 Matchless G3L thumping round the Durham Dales.
SPRIDDLER
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Re: Head stock bearing adjustment

Post by SPRIDDLER »

Quite so, Ron, but it's all in detail in the manuals and I couldn't be ar*sed to type any more out.
I'm keen that youngsters (average age of Club members is 67 and rising) know where to find the information as we old sages won't last forever, unlike our bikes.
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Which taken at the flood............'
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REW
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Re: Head stock bearing adjustment

Post by REW »

SPRIDDLER wrote: we old sages won't last forever, unlike our bikes.
'Course we will, we're baby boomers!
Ron

1951 Matchless G3L thumping round the Durham Dales.
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