Britbike forum

Fork options

Posted By: geordie

Fork options - 01/28/16 6:09 am

So I bent the front end of my 58 model and parts in this part of the world are difficult to get without paying lots of freight, I have heard that A65 forks are another way to go. I believe they look the same from the outside and offer better damping and handling, Is this true ?
Posted By: kommando

Re: Fork options - 01/28/16 6:17 am

Depending on what model you get them from they will look the same and provide better damping.

You need the 66 to 68 version for the 8" Single sided brake hub for the similar brake on the Goldie, or the 66 to 70 from the B44 Victor Special is the same fork but shorter stanchion.

65 and earlier versions lack the damper rod like the original Goldie.

The damper rod gives you 2 way damping with a valve that moves depending on which direction the forks are moving, lighter damping for compression (working against the spring needs less damping) and stronger rebound damping. This is the same technology as the Eddie Dow dampers.

Posted By: Gordo in Comox

Re: Fork options - 01/28/16 12:11 pm

According to my parts books the 66 to 68 A65 and 68 to 69 B44 VS use the same 68-5144 stanchions and other fork bits. Other years I cannot comment on.

The rod damper in those forks works fine for normal road riding.

Gordo
Posted By: rocketgoldie

Re: Fork options - 01/28/16 1:07 pm

TRY [email protected] HE HAS LOTS OF NOS PARTS FOR MOST BSA MODELS.
Posted By: John Alexander

Re: Fork options - 01/28/16 2:18 pm

all these forks will fit, bsa b31,33,bsa a7,a10
goldie john.
Posted By: Dave - NV

Re: Fork options - 01/28/16 4:12 pm

Geordie .. To answer your GS fork question... Are you aware bent fork tubes can be straightened in a press? Many of us have done this.

As I've mentioned before on BB.com, I have fitted Victor and A65 fork Legs to my Goldies for the reason of their rod dampening vs the 'imaginary' dampening of the OEM GS forks. Bear in mind neither of these bikes triple clamps will work, just the legs.

But allow me to elaborate a bit ...
If you are going to use Victor forks there are some issues. The lugs on the sliders face forward so OEM fenders and brackets won't work. The fork tubes/stations are made to be used with the closer spaced triple clamps, so some machining work is required. Better to use the 'short' A65 tubes with the Victor sliders.

If you fit the A65 fork legs/sliders I recommend you use the 'short' A65 tubes. This gives you improved handling and better 'turn in'. BTW, the only clue you have A65 forks fitted on your GS will be the clearance holes in the bottoms of the sliders that are needed to fit the allen bolt that secures the internal dampener. But then a sharp eyed 'rivet counter' may notice the slightly thicker upper fork tube 'bolt'.
Have fun!
Posted By: Gordo in Comox

Re: Fork options - 01/28/16 5:43 pm

Some of the B44 sliders have the bracket at the rear like the GS. This is the 69 B44VS front end that shares all the fork bits except the triples, with the 66-68 A65, including damper and staunchions. However the fork seal holders take different bits than the GS.

Gordo

[Linked Image]
Posted By: kommando

Re: Fork options - 01/29/16 5:30 am

Quote
Some of the B44 sliders have the bracket at the rear like the GS.


Basically all the Unit Singles from 66 onwards with the 7" and 8" Single sided brake have the rear facing tabs, the full width hubs do not. The downside to the 7" is the extra tab welded to the brake side leg for the lug on the 7" brake plate but this can be hacksawed off and then cleaned up on a lathe or left on. Pre 66 on the B40 and C15's like the B40 Enduro Star they do not have the damper rod arrangement and all will have the 7" tab.
Posted By: Shane in Oz

Re: Fork options - 01/29/16 4:56 pm

If it's just the stanchions that are bent, Cob Smith has some very nice hard-chromed UK-made sets available, complete with bushes here
Posted By: Dave - NV

Re: Fork options - 01/29/16 8:16 pm

Gents .. Sadly I'm not familiar with the Victors. The fork parts I used were from a '67 Shooting Star that had a 7" brake as I remember and it had the tabs facing the front.

Gordo I notice in your photo what looks like a 8" ss brake on the B44. I had no idea Victors used this brake.

A question I would bet you could answer for me. If you'll notice in my above post, I mention the 'short' A65 tubes/stantions. The pieces I have were purchased used and I've tried to order A65 repops and received 1" longer tubes. Hmmm Would you please identify which year/model A65s that had this front end. The bikes are identifiable with the 1" 'dropped' top yoke/clamp.
Thanks.
Posted By: Rich B

Re: Fork options - 01/29/16 8:49 pm

62 - 65 unit twins had rhe droop yokes with the shorter stanchions (except Hornet & Cyclone). None of these forks had rod dampers and actually shared bits with the pre-unit forks.
Posted By: Gordo in Comox

Re: Fork options - 01/29/16 10:55 pm

Dave: The Victor Specials used the 8" single sided front brake for at least 68-70. It has the same slightly wider drum as used by the A65.

The shorter fork stanchion is part number 68-5030. I only go back as far as 1965 in my parts books but in that year it was the T/R and L/R with the shorter forks. Of course they had no real dampers.

I am just putting the original 1965 front end back on by A65 and will use a set of Dow type rod dampers I got from George Prew.

Gordo
Posted By: Don P.

Re: Fork options - 01/30/16 12:34 am

Hi Dave,I ordered tubes from S+M Motor Co. They are the correct
length.They are listed as part# 68-5144 Product 40/127
They list them to fit C15 67-68 and A50/A65 1964-68
Hope this helps
Posted By: Gordo in Comox

Re: Fork options - 01/30/16 1:57 pm

Don: The 68-5144 is the full length tube used on the rod damper machines with the normal triple clamps after 1965. They were used on twins 66-68 and the B44 VS 68-70. The short tube was only used on twins with the cranked down top triple and maybe some of the early singles. One must also be aware that all the rods in the rod damper units are not the same length.

Gordo
Posted By: GS DAVE

Re: Fork options - 01/30/16 3:48 pm

Or if your so inclined you could spend weeks in the garage making your own, with jap damper internals and stanchions.
Not for the rivet counters and a hell of a lot of work !!!
Have them assembled now but not done a road test yet smile
[Linked Image]
Posted By: Don P.

Re: Fork options - 01/30/16 10:50 pm

Hi Gordo,Thanks for the info on tube length.Would there be any noticeable differences between the A65 front forks and just using
the eddie dow dampers on original fork setup?I have both and it would be helpful to know if one works better so I can decide which way to go.
thanks,Don
Posted By: Gordo in Comox

Re: Fork options - 01/31/16 12:07 am

Don: I have as yet no experience with the Dow type damper. I took my original 1965 A65 frontend off years ago and put on a complete later rod damper frontend to get the damping and the TLS brake. Of course to avoid raising the frontend with the longer tubes I had to take off the cranked upper triple in favour of the normal version. This change meant that my headlamp ears were too short and I could not use the unique front mudguard mount the T/R used.

That said, I am putting the original bits back on to try out the Dow dampers for awhile because I am curious as to how they might work on a GS project with the original type forks.

I think though that GS Dave has the right idea in using more modern innards. Every time I look at Bultaco or Betor fork dampers it makes me think that the BSA rod dampers are sort of homemade with all those little bits on the damper rod. With that in mind I might as well try out the Dows.

Gordo
Posted By: Rich B

Re: Fork options - 01/31/16 8:05 am

I have Dow dampers on 2 bikes, my LC replica and a GS. Yes they do work, much better than the stock sort of dampening. But, the Dow dampers are not as "plush" in action as the rod damper forks.

The Dow dampers are a bit harsh in action. Really light fork oil (5W, 10W) seems to work best for me.

You can buy Dow dampers from several sources. There are also drawings on the A10 forum (and probably other places) to make your own. I would like to make a set for one of the other pre-units and play with hole sizes to soften the action.

The rod damper forks, with good (read not worn out) pieces don't work bad. IMO, the best forks used by BSA. Fairly plush in action, reasonably well controlled. But definitely not a Betor front end. Be interesting to see if Betor/Bultaco internals could be adapted.
Posted By: Jerry Roy

Re: Fork options - 01/31/16 1:51 pm

http://www.a7a10.net/forum/index.php?topic=2895.0

and a little lathe work.

JR
Posted By: Dave - NV

Re: Fork options - 01/31/16 4:36 pm

Gents .. I'm still a bit confused re 'short' A65 fork tubes for rod dampeners front end. Gordo you have mentioned the 'early A65s with short tubes p/n 68-5030 but without rod dampeners? For a fact years ago I bought a A65 front end with rod dampened 'short' tubes that are fitted to my GS 'special'. Any/all help would be much appreciated as I don't have a A65 parts book... sheeze.

Speaking of Dow dampener inserts. For several years I've helped my GER GSr friend Peter Huber sell his repop Goldie pieces. One item was his copy of the Dow dampeners that I've sold ~ 10 sets to GSrs. I have a couple of sets left on hand I'll sell for US$90 or $125 with SS fork caps.
Posted By: Tribsauk

Re: Fork options - 01/31/16 4:44 pm

I have genuine Dow dampers fitted to my Tribsa forks which also have the lengthened top fork bushes fitted which came with the fork kit from Dow, these work well with a 10w fork oil.I also have a pair of lower fork sliders from a ex wd BSA B40 these have internal dampers but have the brazed on lug for a 7" single sided hub. Was thinking of using these on my Tribsa as the sliders have a bit of wear, just have to remove the brazed lug so I can fit 8" single sided hub which is fitted with a Dow TLS brake plate.I think the ex wd B40 fork sliders can still be found old stock as the british army was still using the B40 early 70s.. Dave
Posted By: geordie

Re: Fork options - 01/31/16 6:02 pm

Wow thanks guys, I think.... my head is spinning
Posted By: Gordo in Comox

Re: Fork options - 01/31/16 6:14 pm

Dave: My parts books only go back to 65 for the unit engines. That year for the A65 lists two fork tubes, 68 5030 for the cranked top triple and 89 5061 for the others. Both of these tubes would not use the rod damper that came out the next year. 89 5061 is also the Gold Star scrambles tube.

Those tubes would all have two small holes near the bottom like these as far as I know.

[Linked Image]

In 1966 the A65 does not list the cranked top triple and lists only had one tube, 68 5144 and shows the rod damper for the first time. The bottom holes for these tube are different from previous tubes. There are now four larger holes spaced evenly around the tube and all the same distance up the tube. They look like this. The bottom screw in fitting may or may not be the same as the one shown here.

[Linked Image]

To switch to the BSA rod damper you would only need top cap with the threaded inside hole (or the through hole with a nut on each side) the damper bits and the slider with the hole at the bottom to anchor the damper tube. The top bushing is not secured with a circlip like the earlier forks so you most likely would need a different seal holder set up.

As for the tubes one could take the shorter early A65 tube and use it in a rod damper setup but I would think that the holes at the bottom would need to be changed to the four larger holes vice the two small ones for it to work as BSA intended.

However there may well be a shorter tube from one of the non A65 models. The B44 Victor Enduro used a rod damper fork with tube 41 5115 (vice 68 5144) using the same damper tube as the A65 but with a different damper rod 41 5128 vice the A65 damper rod 68 5143. I do not know how long the 41 5115 tube is.

Gordo

© 2020 Britbike forum