Girder fork top spring mount

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alan.moore
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Girder fork top spring mount

Postby alan.moore » Tue Aug 07, 2018 9:48 pm

Getting to know my new WNG I noticed the Girder spring top mount appears to have a separate 'top hat' where the mount fits into the upper girder yoke. My 1939 does not have this fitting. Looking at the 1941 WNG parts list and the VH list the mount is shown in both cases as 4612-32, no mention of this extra bit.
So.... in the first of many questions which I feel sure will follow, is this part an original WNG addition?

Spring top mount.jpg
Top mount WNG


Spring top mount VH.jpg
Top mount VH


Cheers
Alan
1939 VH Redhunter;1942 RN WNG;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
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Re: Girder fork top spring mount

Postby nevhunter » Wed Aug 08, 2018 12:46 am

Any kind of spacer there would affect the strength of the fitting D10/39 as it's tapered and fit's into D10/104. No W/NG's I've seen have such a spacer. It may have been fitted with a longer bolt to compensate for spring sag. That would subject the bolt to too much strain as you've lost the function if the papered fit in locating it. Nev

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alan.moore
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Re: Girder fork top spring mount

Postby alan.moore » Wed Aug 08, 2018 12:41 pm

I haven't dismantled it but removed the bolt and the additional spacer looks as though its tapered at both ends, at the bottom to accept the original taper (D10/39) and at the top to fit into the top yoke (D10/104). It is a machined piece just for this purpose. It gives an increase of 1/2 inch.
SDC11445.JPG


SDC11443.JPG


has anyone got a parts book later than 1941, maybe its a later addition?

Cheers
Alan
1939 VH Redhunter;1942 RN WNG;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
http://cloggymoore.wix.com/triumph-pre-unit-6t

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simon.holyfield
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Re: Girder fork top spring mount

Postby simon.holyfield » Wed Aug 08, 2018 1:37 pm

I've got a few parts books Alan. I'm working away from home for the next couple of days but I'll be back at the end of the week.
cheers

Simes

'51 Square Four, '58 Huntmaster, '42 W/NG, http://ariel-square-four.blogspot.com

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Re: Girder fork top spring mount

Postby nevhunter » Thu Aug 09, 2018 3:27 am

It's still weaker The additional spacer piece has a smaller outer dia than the top fitting has. I've never seen one fitted (but that doesn't mean it's not a part.) Is the spring the normal length?. If you are sure the lengthened bolt is high tensile or something decent and the tapers fit well, it's probably OK Nev

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Re: Girder fork top spring mount

Postby ian.scott » Fri Aug 10, 2018 8:47 am

I had to fit a similar spacer to my VH as the front mudguard continually crashed into the girder fork bridge casting in spite of fitting a new OS spring. This was initially when used in trials trim but since our roads have deteriorated into their current state it is needed on the road as well.

Ian

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alan.moore
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Re: Girder fork top spring mount

Postby alan.moore » Fri Aug 10, 2018 1:55 pm

Thanks for that Ian. Is the spacer an Ariel part or did you make one yourself?

Cheers
Alan
1939 VH Redhunter;1942 RN WNG;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
http://cloggymoore.wix.com/triumph-pre-unit-6t

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Re: Girder fork top spring mount

Postby ian.scott » Fri Aug 10, 2018 2:56 pm

I made it myself. Originally it was only roughly made to try out but as it solved the problem so I and tidied it up and refitted it.

Ian

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simon.holyfield
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Re: Girder fork top spring mount

Postby simon.holyfield » Thu Aug 16, 2018 8:23 pm

simon.holyfield wrote:I've got a few parts books Alan. I'm working away from home for the next couple of days but I'll be back at the end of the week.


Nothing in the parts books...
cheers

Simes

'51 Square Four, '58 Huntmaster, '42 W/NG, http://ariel-square-four.blogspot.com

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Re: Girder fork top spring mount

Postby paul.jameson » Sun Aug 26, 2018 10:14 pm

This is definitely a new one for me. There are 2 versions of the girder spring top mount but you have the same type on both your bikes which has a flat top surface above the fork spring. The earlier type has a more conical surface. It took me years to spot the difference between the two. That difference is the angle of the "slots" which take the top of the spring. The early type has the slots tapered the same way as the spring coils. The later type has the slots tapered the opposite way, presumably to grip the coils of the spring better. Clearly this was seen as a problem since the drawing for the spring instructs you to fit the spring to the top mounting before enamelling.

Given this evidence of problems and developments in this area I can only conclude that your extra fitting is another attempt to solve the problem.

The problem, in my experience, is that the top mounting comes loose in the taper fitting in the top of the fork girder. No way could I keep the one on my RH tight so I used to run it slack which it survived happily for many years. Then the threads stripped in the top mounting so I had to go up a thread size (but the same hex size on the bolt head for appearance sake.) I still run it fairly loose and it gives no problems. Despite many bumps ridden over, the spring top mount has yet to become detached and if I haven't done it by now, I don't think it is going to happen. So perhaps the problem is one which causes fairly instant concern, but in the end, doesn't matter.
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser.


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