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'63 Atlas - Long Vs Short forks #235083 01/29/09 9:39 am
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Hector Catre Offline OP
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Hi All,

My Triton build is coming along except I've run into a snag: My front forks will not compress under weight.

The forks disassembled compress just fine, but I believe I might have the wrong springs in my roadholders. The ones I have may be too long.

As it is I had to put a lot of force just to mount them on the triple trees, having to use a couple of rachetings straps to to the job.

The question I have is: is there such a thing as long vs short roadholder external spring? If so, does anyone know the uncompressed length of each?

Thanks
H


- Triton Project
-- '63 Norton Atlas
-- '56 Triumph Thunderbird 650
- '72 BMW R75/5 Cafe Racer
- '73 Yamaha XS650
- '75 Yamaha XS650
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Re: '63 Atlas - Long Vs Short forks [Re: Hector Catre] #235084 01/29/09 9:45 am
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Hector Catre Offline OP
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Also forgot ... would anyone have the part number for the shorter springs (if they do exist)?


- Triton Project
-- '63 Norton Atlas
-- '56 Triumph Thunderbird 650
- '72 BMW R75/5 Cafe Racer
- '73 Yamaha XS650
- '75 Yamaha XS650
Re: '63 Atlas - Long Vs Short forks [Re: Hector Catre] #235120 01/29/09 3:34 pm
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Ron Leisner Offline
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Perhaps you have springs from a G15/N15? The Matchless framed hybrids had longer tubes and springs and damper rods. The correct Atlas part number for the spring is 18813.
Ron L


Ron L
1973 MkV 750 Roadster
1974 850 Interstate
1975 850 Cafe Racer
1968 750 Fastback
1967 P11
1969 Ranger 750
Re: '63 Atlas - Long Vs Short forks [Re: Ron Leisner] #235133 01/29/09 5:39 pm
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oilyrag Offline
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Short roadholders on an Atlas should have INTERNAL springs.


Oil is always cheaper than metal
Re: '63 Atlas - Long Vs Short forks [Re: oilyrag] #235145 01/29/09 6:33 pm
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marinatlas Online Content
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Hi there, are they roadholders with external springs or internal springs ???
if internal they all are the same lenght 'even the N15.
if external the manx should be something like 9.5", the long roadholder 11.75 ",and if G15 let me know , cause I am building from scratch with external springs and can't find their lenght , but longer than the 11.75" Ihad fitted recently.

Re: '63 Atlas - Long Vs Short forks [Re: marinatlas] #235160 01/29/09 7:43 pm
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Hector Catre Offline OP
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Is the Manx the short one? Is the correct part number 18813 for the manx ones?


- Triton Project
-- '63 Norton Atlas
-- '56 Triumph Thunderbird 650
- '72 BMW R75/5 Cafe Racer
- '73 Yamaha XS650
- '75 Yamaha XS650
Re: '63 Atlas - Long Vs Short forks [Re: Hector Catre] #235166 01/29/09 8:01 pm
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The Artful Bodger Offline
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The Norton Manx had a flat lower yoke where as the Atlas and Dominator yokes curve downwards. To use external springs and an Atlas yoke you need to find a shorter spring than as used on the Manx. Try Clubman Racing or Unity.
Cheers,
Alastair


Black Shadow of the Vincent falls on the Triumph line,
I've got my motorcycle jacket but I'm walking all the time...

1942 BSA M20
1956 Pre-unit Triton project/money pit

http://tritonproject.blogspot.com/
Re: '63 Atlas - Long Vs Short forks [Re: Hector Catre] #235173 01/29/09 8:48 pm
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Hector Catre Offline OP
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I just took a look at the Clubman racing site.

The tubes for the dommie, atlas, etc where longer then those for a manx

#C013 - Commando 23.161
#A005 - Featherbed (Atlas, Dommie, etc.) 21.843
#A002 - Manx 20.375

Shouldn't the manx springs work because the tubes are longer?


- Triton Project
-- '63 Norton Atlas
-- '56 Triumph Thunderbird 650
- '72 BMW R75/5 Cafe Racer
- '73 Yamaha XS650
- '75 Yamaha XS650
Re: '63 Atlas - Long Vs Short forks [Re: Hector Catre] #235218 01/30/09 6:21 am
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The Artful Bodger Offline
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The manx fork tubes are shorter because the top yoke is not flat like those of the dommies and atlas, but slopes downwards - apparently to aid looking over it when your chin is on the tank?

The bottom yoke is flat on the manx to allow more travel in the forks because of the outside springs, although this resulted in the two clamping points being much closer together between the top and bottom yoke.

If you are going to use outside springs you need to find a shorter spring or it will bind with little travel, or else use internal springs.

Hope this helps,
Alastair


Black Shadow of the Vincent falls on the Triumph line,
I've got my motorcycle jacket but I'm walking all the time...

1942 BSA M20
1956 Pre-unit Triton project/money pit

http://tritonproject.blogspot.com/
Re: '63 Atlas - Long Vs Short forks [Re: Hector Catre] #235221 01/30/09 7:55 am
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marinatlas Online Content
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Hi hector , maybe this website could be of any help :
http://www.members.shaw.ca/randell/roadholders.html


Moderated by  Dave Comeau 

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