G15 damper length

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Jul 2, 2015
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Long shot, but...

My G15-CS dampers were lost in the mail...package arrived sans contents. (Don't ask; I am trying to move on and achieve closure!)

Replacements seem near-unobtanium. I have, however, taken this opportunity to inquire about a custom Lansdowne damper and Don has been receptive.

Is there a chance that anyone can measure or happens to know the total length of a G15 damper assembly, including tube and rod in fully extended position? I can try to interpolate, of course, but a direct measurement would be best.

Would also like to know length of thread on the rod which mates to the fork top bolts and also the height of the boss at the base of the damper (both of which I would include in overall length...)

Thanks very much, Merry Christmas, and Happy Holidays.

-Mike
 
Total length of the damper tube is 27.5 cm, or slightly less than 11"
I believe rods are the same as Commando, but all screw threads are different.
( cycle, I think..)
G15 damper length
 
Thank you very much, Ludwig! Appreciate your time with that.

My dampers were 030440 with the clip-on bushing top, so unfortunately I am unable to interpolate an answer off of what I presume is the 030037 damper tube. The total length of either style unit including damper and rod would be ideal.
 
Isn't your G15 supposed to have a Norton fork and damper?
( but with 2 " longer stanchions and damper tubes)
My pic. is from an original, late N15 cs damper.
You have many options, like using a std Commando damper with 2" longer rod ( easy to make) combined with a 2" longer spring or 2" spacer on top.
 
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Mine is a 1965, which has a Roadholder stanchion and slider, but internals derived from a Matchless teledraulic unit. (Damper PN 03-0440). The damper rod is different,and the rod slides in a bushing held to the damper tube by a spring clip rather than a screw-on cap. Rod is also a narrower diameter, .310" if I recall correctly. Uses external springs as stock, as well.

The succeeding years switched to the modified Roadholder internals you describe (PN 03-0037 damper). Overall length of both damper/rod setups when assembled must be very close or identical, but I would not stake a claim that the damper tubes themselves are identical in length, especially given the differing methods of attaching the top cap/bushing.

Having difficulty embedding a photo from my mobile but here is a link: https://flic.kr/p/2hXFPky
 
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Ok, I got it now.
Is there a reason why you want to keep the internals original?
There is a lot you can do to improve the forks.
I see you also installed a belt drive.
I have one on my N15, but in a modified Commando primary, which solved a lot of problems, like centering the alternator.
Mine is probably the last hybrid ever built, but now with 850 engine and countless mods (avatar)
btw, shouldn't you take any precautions about oil migrating from the gearbox onto your clutch plates?
Good luck with your built.
 
I am hoping to replace the internals with a Lansdowne damper cart set, but need the length of the assembly in order to have Don make it the proper length for the G15
 
Piero has offered to get me the full measurement once he's back home in a week or so...Don has agreed to make the cartridges based on that measurement, so things look pretty well set.

Also have new stanchions enroute from Walridge, and a pushrod seal kit as well. Hopefully it's back on the road soon!
 
I am able to assist as well. Complete dampers off an early G15CS are in my collection.

Les Emery (Norvil Motorcycles) stocks alloy (dural) damper tubes to 030037 design; He may have the dimensions to fabricate 030440 as well.
He still lists some parts for these "hybrid" forks. You may want to get in touch with him.

-Knut
 
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Knut, thanks a ton! If you have that complete measurement, I will take it soon as you're able.

Been in touch w Les but the recommendation all round is to convert to roadholder internals (030037). If I am going to spend the cash to do that, I might as well put it towards the Lansdowne carts and better performance that doesn't need retrofitting to work, by my thinking.
 
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Piero has offered to get me the full measurement once he's back home in a week or so...Don has agreed to make the cartridges based on that measurement, so things look pretty well set.

Also have new stanchions enroute from Walridge, and a pushrod seal kit as well. Hopefully it's back on the road soon!
Please,
Wayt another two days.
Ciao
Piero
 
My 1974 G15 had the roadholder forks but with Matchless damper (the same of P11) and external springs (no internal spring).
As sugested here i have update the forks with internal spring only (external anymore).
Ciao
Piero
 
Piero, thanks again! Really appreciate your help and understand whatever time it takes. Same to you, Knut.
 
Hi.
My 1967 AJS 33 CSR damper with rod and spring in place measures 77,4 cm.
If you want i can keep the new measure removing spring.
Hope this help.
Piero
 
Piero, that's great, thanks!

Would removing the spring change the measurement? Mine has external springs so I am not sure how it works with yours.
 
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Piero, that's great, thanks!

Would removing the spring change the measurement? Mine has external springs so I am not sure how it works with yours.

My 1964 G15 MK2 had the external spring but with the Matchless dampers.
I have left this dampers but removed the external spring with internals like late G15.
Ciao
Piero
 
I am mocking up a leg with Piero's damper length just to ensure it is correct for my bike (model, year, manufacturing variances etc.)

Could someone provide the length of the assembled stanchion above the slider? (Top cap, or preferably lower edge of top cap, to top of slider on an unloaded fork leg...or to top of axle clamping hole...). Just to make sure that length provides the right overall fork length.

Knut, internal damper double-check still also much appreciated for the same reason, if you can get to it over the weekend.

Thanks again to everyone for the help! Hope to have the dampers ordered Monday.
 
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