Author Topic: S6 Electrics  (Read 3614 times)

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Offline Chris

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S6 Electrics
« on: 02 Feb 2014 at 15:18 »
HI All
 Can anyone inform me of the detailed construction of the electrical connection that runs through the lower top tube of the frame of the T/S 5/6 and derivatives. I understand that there is an insulator at each end with a brass screw terminal connected by a conductor Rod? or Wire? A detailed sketch would be appreciated. Also the original specification includes a BTH cutout I have one of these but do not know where it was originally mounted. It is on a flat steel plate with a single mounting hole in the overlapping end of the plate as shown in the illustrated parts list. My S6 is an early one with the battery cradle supported under the front of the petrol tank over the front cylinder. Chris.

Offline eddie

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Re: S6 Electrics
« Reply #1 on: 02 Feb 2014 at 18:35 »
Hi Chris,
             Regarding the wire through the top tube - my 1930 S6 also has this. It consists of a flanged insulator at each end that is a neat fit in the frame. Through this insulator there is a countersunk brass bolt (2BA?) with the head extended by about 3/16". This bolt is cross drilled on the countersink for a 1/16" pin and also drilled in the end to accept the wire. The insulator is drilled and deeply countersunk to match the bolt and slotted for the cross pin (the slot has to be deep enough to be clear of the cross pin when all is assembled). The bolts are then soldered to each end of the wire. The insulators are then fitted over the bolts with the pins located in the slots, and the insulators pushed into the frame (the wire needs to be about 1" longer than the fitted length). A locknut now secures the bolt in place and pulls against the countersink to spread the insulator and wedge it into place. Connection to this is now made with a ring terminal and second nut.
   Regarding the original BTH cutout - mine is mounted a sheet steel bracket (about 20 gauge). One end is joggled to clear the fixing screws for the cutout and is attached to the frame with a 1/4" bolt through the front frame lug (may be the end of the front fixing for the tyre inflator) (you have to be careful not to trap the wire inside the tube!). The other end of the bracket is folded down and profiled to rest on the top of the frame tube.
    Hope this helps,
          Regards,
                        Eddie.

Offline Chris

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Re: S6 Electrics
« Reply #2 on: 03 Feb 2014 at 09:00 »
Many thanks Eddie
Chris.

Offline aphex

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Re: S6 Electrics
« Reply #3 on: 03 Feb 2014 at 19:05 »
Hi , here's some pictures of the BTH cutoff.
Regards,
Sven

Offline Chris

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Re: S6 Electrics
« Reply #4 on: 04 Feb 2014 at 08:22 »
Hi Sven
Thanks for the photos and the solution to mounting the cutout. It looks a possible fix but I do not think it original as the hole in the base plate of the cutout is only 1/4" diameter and the spindle for the gearlever is larger so would involve drilling the base plate. Any other ideas as to what was original?    Chris.

Offline eddie

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Re: S6 Electrics
« Reply #5 on: 04 Feb 2014 at 09:05 »
Hi Chris and Sven,
                           The bike in the photos looks to be a later version of the S6 (Cast iron brake drums, battery mounted at back of petrol tank, and late type 4 speed gearbox). On my 1930 model, the BTH cutout is mounted vertically on the lower tank rail so that it is concealed in the petrol tank tunnel. The mounting plate for it is only secured at the front end, with the rear end profiled to rest on the tube. (On my bike, I have attached the rear of the mounting plate to the battery carrier, as I don't like the idea of one end vibrating against the tube - this could cause the onset of all sorts of electrical problems!). The 1/4" bolt that secures it goes vertically through the socket of the front lug for the lower tank rail (depending on the model - S6 or T6 - this fixing may also include the front mounting for the tyre inflator).

   Regards,
                 Eddie.

Offline Chris

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Re: S6 Electrics
« Reply #6 on: 07 Feb 2014 at 09:09 »
Hi All
Folowing Eddie's advice above I have now manufactured the brass screw terminals complete with their cross pins and having fed the conductor wire through the frame tube and have soldered the conductor into the end of each screw terminal. Eddie informed me in a personal email that the insulators were originally made from "Tufnel" but were prone to cracking and recommended the use of black nylon. I have some black nylon bar but too small in diameter to provide a decent sized head to match the frame tube diameter but using this just for a trial it worked. I will be attending an auto-jumble this coming Sunday when I will be able to obtain the correct diameter when I can make two matching insulator bushes of the correct size. Points to observe are that it is not very easy to feed the conductor wire through the tube as the gear change support goes through the frame tube leaving only a small space above or below it to thread the wire through. Also the lugs at each end of the frame tube can catch the end of the wire needing patience and twiddling to get it through. Because of these obstructions mainly the gear change shaft it is not possible to feed the conductor through the frame tube with its screws soldered in place. The screw at one end therefore has to be soldered in situ on the bike. The insulator bushes when finish machined can then be pushed into each end of the tube having pushed the screw terminals through the centre hole and aligned the 1/16" diameter cross pin with the slot in the insulator. This prevents the screw turning as the securing nut is tightened expanding the insulator bush to grip the inside of the frame tube. I will submit photos when the job is completed. 
Chris

Offline eddie

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Re: S6 Electrics
« Reply #7 on: 07 Feb 2014 at 10:00 »
Chris,
         The whole assembly can be soldered up off the bike providing you remove the gearchange shaft before threading the wire through the tube. (It might also pay to remove the front mounting for the tyre inflator!).

    Regards,
                  Eddie.

Offline Chris

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Re: S6 Electrics
« Reply #8 on: 07 Feb 2014 at 10:45 »
Thanks Eddie. Never thought of that. I had assumed that there was a tube right through the frame tube supporting the bolt. It would certainly have been easier soldering the conductor assembly off the bike. Incidentally another point occurred to me when assembling is that the 1/16" diameter rods must be shorter than the diameter of the insulator bushes and prevented from moving subsequently as they will short out the conductor to earth if they touch the inside of the frame tube. I secured them with Loctite. Regards   Chris.

 

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