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Handlebar clutch switch as a brake switch?
Posted: Mon Mar 27, 2017 2:32 pm
by jjwithers
I'm building a bike that is a hybrid of parts.
The bike had the brake switch at the master cylinder but the master I replaced it with does not have a switch area.
I'm looking at the handlebar mounted clutch switch and the right side controls look like they would take the same type of switch.
The Fiche on MAX shows a switch for each side of the controls, but it only states it is a clutch switch for the left side.... I'm thinking I can get a second one and use it on the right side as a brake switch. Or is there something I am missing?
Re: Handlebar clutch switch as a brake switch?
Posted: Mon Mar 27, 2017 7:38 pm
by melville
Yes, I believe the drum brake bikes (R60/6 and maybe /7) were set up that way.
Re: Handlebar clutch switch as a brake switch?
Posted: Mon Mar 27, 2017 11:10 pm
by Seth
So yes, the clutch normally closed switch will work, but you'll obviously have to drill out the lever housing to mount the switch. You have to be sure the housing is thick enough not to break, assuming you're not using one that already has such a hole.
Although not as clean, my 75 Honda CB400F has a hydraulic switch similar to the original BMW switch mounted in a casting that connects the upper brake line to the lower.
Re: Handlebar clutch switch as a brake switch?
Posted: Tue Mar 28, 2017 1:08 am
by Bamboo812
I did that same mod, the switch fits under a lip on one end of the square hole, and the screw holds it in place. I seem to remember I had to lengthen the pushrod a bit to make it work. 1976 R90/6 with a /5 front end:
Re: Handlebar clutch switch as a brake switch?
Posted: Tue Mar 28, 2017 1:39 am
by jjwithers
Seth wrote: ↑Mon Mar 27, 2017 11:10 pm
You have to be sure the housing is thick enough not to break, assuming you're not using one that already has such a hole.
The throttle housing and brake lever has a section, with the hole and thread that looks like it will work for that switch.
And Bamboo812, you put drums on a /6? why?
Re: Handlebar clutch switch as a brake switch?
Posted: Tue Mar 28, 2017 3:44 pm
by Bamboo812
Hydraulics are over rated, and the original single disc brakes in that bike needed everything (including a new hub). BMW wants $450 for a replacement disc these days, too. Think about this; the only real difference between the R50/5 and a R100/7 is cylinder bore, not weight. Drum brakes, properly sorted, will stop either in the same distance...
Re: Handlebar clutch switch as a brake switch?
Posted: Tue Mar 28, 2017 4:51 pm
by jjwithers
Here is an update -
The switch works in my perch but the handle has an indentation in it so there is not a tab that activates the switch. I went through all my spare handles and the left side does not have that indentation, the right side handles do. So... i Drilled a small hole in it, tapped it, put a screw in it and now it will activate the switch.
Re: Handlebar clutch switch as a brake switch?
Posted: Tue Mar 28, 2017 6:54 pm
by Bamboo812
Ah, that's right. On mine, I machined a little metal cap for the pin to lengthen it. Edited my post for clarity.
Re: Handlebar clutch switch as a brake switch?
Posted: Sat Apr 08, 2017 11:06 pm
by jjwithers
I got everything wired today and the clutch swap into brake switch works!