BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: KernowPete on 21 Jan, 2024, 16:13

Title: Calling fork experts
Post by: KernowPete on 21 Jan, 2024, 16:13
Doing a strip down of the front forks of my C15T. The bike seems to be a bitsa with C15T frame, road bike subframe and mysterious forks. I think they are the C15T forks (heavyweight) but with the bottom nut from the Bantam Bushman. It also looks like someone has fitted some additional damping held in place by the bar secured to the top nuts.
Anyone able to identify/confirm what these fork parts are and if they work ok together? I need to replace the bushes and seals. Quite tempted to get another pair of forks if these remain a mystery.
Title: Re: Calling fork experts
Post by: scifi on 21 Jan, 2024, 23:14
It's been a very long time since I had a C15, but I seem to recognise the one way valve on the end of the rod.   Hope you get them to work the way you like them.  Selecting, or mixing, the right grade of oil helps.   I liked mine fast operating, as I thought I would be hitting bumps quicker than some... :) :)
Title: Re: Calling fork experts
Post by: KernowPete on 22 Jan, 2024, 20:26
Thanks sci-fi. I think I've identified the bushes, seals and gaiters so hopefully have it sorted soon  :)
Title: Re: Calling fork experts
Post by: KernowPete on 23 Jan, 2024, 17:49
So if anyone's interested it turns out the extra damping is a pair of Eddie Dow damping rods like this -
http://www.britishcycle.com/Products/546/546_92.htm
So it seems like an upgrade from the standard heavyweight forks as the extra parts give rebound damping to forks that otherwise wouldn't have them. I think I might need to go with a lighter oil for these.
Only remaining mystery is the bottom nut type.
Title: Re: Calling fork experts
Post by: Stubaker58 on 24 Jan, 2024, 07:24
That is interesting, a worthwhile upgrade?
Title: Re: Calling fork experts
Post by: KernowPete on 28 Jan, 2024, 07:15
So new bushes and seals have arrived but sadly the sliders are so badly worn the bushes were too tight and got jammed up. A very light hone later and they're too loose with a noticeable clunk as the stanchion is rocked side to side. The sliders for this bike don't seem available new so I seem to have 4 choices-

1) put it back together as is and hope for the best (not happening)
2) try and find some less worn forks/sliders (bit of a gamble)
3) put the front end off a different/more modern bike on it (don't want to as it's classed as historic)
4) make up new tube sections for the sliders and reuse the ends

Anyone done no.4? Seems doable if I can get the ends off ok. I think the bottom end casting would be ok but the top looks tricky as it seems to be tack welded and brazed. Might buy another dead slider off eBay to play with
Title: Re: Calling fork experts
Post by: neil1964 on 29 Jan, 2024, 13:56
Might be having a look at Vale-Onslow as they had some fork legs listed last week.
Other option is hone the legs to specific size and get a couple of new lower bushes to suit.
That way you get really good fitting bushes.
Title: Re: Calling fork experts
Post by: KernowPete on 29 Jan, 2024, 17:30
Thanks Neil, as it happens I ordered one of the sliders NOS from vale onslow yesterday. Should arrive tomorrow. That just leaves the other side. Quite tempted to do the new tube idea. Not sure how I can successfully hone right to the bottom of the bore with the slider in tact as there is a conical part of the lower lug that sticks up about 2 inches into the slider.