1956 onward fork damper tube

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alanengineer
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1956 onward fork damper tube

Post by alanengineer »

Hi
I have just split a pair of forks into tiny pieces. On inspection the fork damper tubes are both different. The thicker end on one is about an 1" long and on the other, its about 3" long and the cross holes are very different diameter, something like 1/8 and the other 1/4.
The parts book shows something in between.
Any suggestions
Its going on a 56 G9
SPRIDDLER
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Re: 1956 onward fork damper tube

Post by SPRIDDLER »

alanengineer wrote:..... the cross holes are very different diameter, something like 1/8 and the other 1/4.
The parts book shows something in between.
I wouldn't worry, Alan. If one is 1/8 and the other a 1/4 the net result will in fact be 'something in between'. :rofl:
'There is a tide in the affairs of men
Which taken at the flood............'
alanengineer
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Re: 1956 onward fork damper tube

Post by alanengineer »

Thanks Spriddler.
i would think the rebound might be uneven and make it look as if i cant ride in a staight line
JimFitz
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Re: 1956 onward fork damper tube

Post by JimFitz »

Hi Alan

I had a similar issue on my G12 forks. The thicker ends were the same length but the drillings were a different size. I cut a small square of 15mm copper water pipe wall and soldered it over the larger hole using silver solder with bakers fluid and then redrilled it the size of the smaller hole. It probably doesn't matter if they are different sizes but while they were all apart it made sense doing it.

Jim
Too old to Rock and Roll but too young to die.

1952 G80 rigid, 1960 G12 DL / Watsonian Monza, 1954 G80S.
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robcurrie
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Re: 1956 onward fork damper tube

Post by robcurrie »

Some modern motorcycles' dampers have different functions, one side does compression and the other does rebound damping! You will see this on Moto Gp 'bikes.

Rob C
alanengineer
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Re: 1956 onward fork damper tube

Post by alanengineer »

Thanks for the replies. I cant imagine Matchless coming up with clever solutions like Rob suggests.
As it stands, i have found another fork leg with the longer, big end thats identical to the better one of what i have, so i now have a pair and now working on the assumption that this is probably how it left the factory.
Since i started this thread, i have come across a third type and had it suggested that trials riders had other mods/drillings they machined into the control end of the damper tubes to give them a better edge on damping.
I now wonder where the shorter version that i have came from, could be the start of a new project!
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robcurrie
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Re: 1956 onward fork damper tube

Post by robcurrie »

I wasn't suggesting that AMC was 50 years ahead with their fork design, I was just pointing out that the difference between the two sides probably doesn't matter. ;)

Rob C
alanengineer
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Re: 1956 onward fork damper tube

Post by alanengineer »

Hi Rob.
Sorry, i did read your post as it was meant to be read and my reply was a bit unconsciously blunt ,Sorry.
I can see the theory, but im not sure it could be carried out with the bracing we have on our bikes. Im not sure what the difference would be and whether we would even take any notice of the difference if we did. Im just happy to have two sides the same so i know both forks should react the same
Alan
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GrimJim
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Re: 1956 onward fork damper tube

Post by GrimJim »

I had a very similar experience. I found this damper tube in one leg of the forks of a 1963 G12. The two holes near the bottom are about 6mm (15/16") and the single
hole near the top is 4.5mm (11/64). The damper rod assembly and bottom fixing bolt were as standard. I bought a second hand replacement from Steven Sturby as I
thought the effect on the handling might be a bit peculiar.
Jim
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GrimJim
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Re: 1956 onward fork damper tube

Post by GrimJim »

IMG0178A.jpg
Photo didn't upload.
Jim
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