Clutch cable routing (1965 B40F)

[Phil C]

Hello everyone, It's the moment you've been waiting for: here are details of the route my clutch cable takes (try to contain your excitement.)

The attached photos show that the cable goes from the handlebar lever, across the top of the headlight, then down and across to the lefthand side of the engine, then along to the rear of the engine, and across to the clutch actuating arm.

I guess that a clutch cable should be routed as directly as possible, whilst avoiding any pinchpoints or tight bends, and having enough slack to withstand a full turn of the handlebars.

Mine seems to take a bit of a roundabout route? Esp the first bit where it goes bellowing over the top of the headlamp.

Any comments please? What is the normal route?  Photos of the normal route would be much appreciated.

Phil.

[JulianS]

The cables for the late A10 models and the B25/B44 look very similar to the B40 item maybe one of these has been fitted by a previous owner?

Having said that the outer length of the 1965 B40 cable is shown as 60 inches in my Clarks Cables catalogue which is longer than both the late A10 and 1968 B25 both shown as 48 inches and both cables being the same Clarks part number 733.

[JulianS]

Just found this parts bulletin dated January 1966 showing the B40 cable 40 8612 was superceded by a shorter cable 40 8564 (Clarks show this as 46 inches)

You can even get a new old stock genuine BSA one of these;

https://www.ebay.co.uk/itm/BSA-C15-C25-Clutch-Cable-NOS-40-8564/133297717921?hash=item1f0929c2a1:g:D~MAAOSwnxxeDl~t

[Phil C]

Fancy that. Thanks very much, Julian. Looking at the pic of the NOS cable, the handlebar end looks like mine, but what's that I see at the clutch end? There is something other than the nipple? Is it an adjuster for some reason? Phil

[Phil C]

Oh I see what it is now. So I think I might buy that, unless anybody thinks buying a NOS clutch cable is a bad idea because of its age? Would there be any deterioration? Should I buy a brand new equivalent?

I assume a suitable route from the handlebar lever would be to keep to the left and behind the forks, go along the frame under the tank next to the electrical wires, then drop down vertically to the right of the carb, and then horizontally into the little actuating arm. Please let me know if that's wrong.

Thanks yet again.

Phil

[JulianS]

At the gearbox end there is the ferrule to fit in the housing and an elongated nipple. Quite normal fittings.

You would need to lubricate the cable before use, I would flush through with WD40 to get the years of dust and bits out.

The advantage of an old stock item are that being genuine BSA it is the best chance of getting one to the correct dimensions and that the nipples at each end are brass soldered in position while some newly made ones have molded solder nipples. If you needed to move either nipple to adjust cable length you can do it with brass, with molded solder they just melt away when heated.

If you look at this cable one bay you can see the molding mark on the barrel nipple.

https://www.ebay.co.uk/itm/BSA-C15-1964-67-B40-1965-66-CLUTCH-CABLE-NEW-40-8612-60-OUTER-LENGTH/223476419749?epid=0&hash=item34083b8ca5:g:DtEAAOSwHIlZ1nTm

[Pete A10]

Don't know if the attached photos help with the cable routing Phil. I no longer have the bike so I have just marked up some photos with arrows to show where the cable went. I don't know if the route is genuine BSA or not, it just seemed to be a nice neat route and the curves were not excessive. When I first got the bike it had a very long cable that got caught round your left foot if you weren't careful.
Mine was a 1960 bike and the cable went through a hole in the back of the inner timing side case and the operating lever was actually between the inner and outer timing cases. Yours looks a lot more straightforward and much better accessibility but the route should still work ok.
Even though I bought an new clutch cable I found it was too long for the route I was using and I had to shorten both the inner and outer. I got caught out by what Julian S described - blowtorch on the nipple and it disappeared; luckily I had kept the old cable and used the original brass nipple soldered back on. Rupert Ratio describes the technique well.
You can get most types of cable and fittings from https://www.venhill.co.uk/cables-and-components

[Phil C]

Thanks very much for that, Pete. It looks like the route is about the same as I described I was thinking of. Seeing the photos is very useful.
Btw, very nice looking bike you had there.
Phil

[hoogerbooger]

FWIW my clutch cable stays on the LHS, runs under tank and pops out just above the top engine mounting bolt. Tank has a recess to clear the bolt that provides enough space.

[Phil C]

So that's what that recess is for?! I wondered why it was there. A while ago on this forum someone spotted on one of my photos that the headsteady bolt looked too long and we thought that might be the reason for the recess. I've since shortened the bolt and turned it round, but I've also routed a new rocker oil feed pipe close to the recess, not realising what it was for. Given that the recess is not only on my bike, obviously it has a purpose, and I guess making room for the clutch cable might be it. Anyway, thanks very much, hoogerbooger, that's really useful. I'll route my new cable like yours if I can, ie  assuming it fits when it arrives, and hoping my oil pipe isn't in the way. 

Btw, I see your rocker oil pipe is rubber. Probably more practical than my metal one.

Phil

[Phil C]

Btw, turning that bolt round might not be ideal - it looks very close to interfering with my decompressor mechanism. But as I don't use it, I guess it doesn't really matter.

[Phil C]

Looking again at Pete's cable route, I see his comes out from under the tank further back, which I guess keeps it out of contact with the hot engine.

I'll look at my options when I get the NOS cable.

Thanks everyone.

Phil.

[Phil C]

Looks like this hasn't gone too well. I ordered the ebay item via Julian's link, 40-8564. I now realise the Parts Service Bulletin he kindly posted said we should use a 41-8564 (reduced in length) instead of 40-8612. So I guess when I ordered 40-8564 I ordered the wrong item. I should have ordered 41-8564. Obviously I should have checked more closely.

Anyway, I got an email from the seller asking whether it was for a C15 or C25, as they were slightly different. I now realise he was talking about 40-8564. I replied it was for a 1965 B40F, 41-8564 (I now realise that number was not what I ordered in the first place!)

The cable arrived this morning. Not in any BSA-logo packaging, and no part number attached. I took the old cable off the bike, then offered the new one up alongside the old one, expecting the new one to be shorter. It was about 8 inches longer!

So now I'll contact the seller and ask if I can send it back.  Sigh...

Phil.

[JulianS]

Phil - I thought he was selling 41 8564 - 40 8564 is an exhaust lift cable certainly not a clutch cable. Sorry to confuse.

[Phil C]

Nothing to apologise for, Julian. You are always extremely helpful to me.