Triumph Rat Motorcycle Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
Hooked my normally closed kill switch in line with white wire to ignition switch. Everything works just fine with one minor prob. My kill switch works in reverse. When kill switch is off the bike has no spark. When switch is on, meaning flow should be interrupted, I have spark. I had this happen one other time on a 71 cb350 when I installed an aftermarket kill switch. I don't mind using the switch this way. Works just fine. Just wondering what causes this. I have heard the prob crops up when moving from "open switch" to "closed" or that the coil winding has something to do with it. Any thoughts?
Here is the switch I wound up using. Detent button switch. Decent quality and inexpensive. We'll see how long it lasts.
718495
 

·
Registered
Joined
·
125 Posts
Normally closed means the two wire are shorted all the time, in essence killing the ignition. You should have gotten a normally open switch. Then you would have to press the switch to short the ignition to ground.
 

·
Registered
Joined
·
5,172 Posts
In this case you are not shorting to ground. It is more like a on/off wall switch as you are opening the white wire 'power circuit'

K
 

·
Registered
Joined
·
72 Posts
I wanted to use the one wire dab button on the bars, but not by shorting out the points. ran the ignition through a relay wired as normally closed, and the dab button now goes to ground and causes a momentary open in the relay. I guess the tradeoff is now depending on the relay (and cheap spring) for ignition.
 

·
Registered
Joined
·
222 Posts
One other way to do it is to have the switch earth the coil when pressed. The coil is earthed until the points open which causes it to fire. If you hold the button down and earth the coil it won't fire no matter what the points are doing. Holding the button for a few seconds is enough to kill the engine. I like this option because it is completely independent from the wiring harness and associated handlebar or key switches. If there any issues with the switch you just disconnect it at the coil and nothing else is impacted.

Scott
 

·
Registered
Joined
·
15 Posts
Discussion Starter #8
Thanks for replies. The button actually does exactly what I want it to do. I want the button with detent. I want the on/off feature--not the cutout feature. Issues is that it just works in reverse. Which again, is not a big deal. Just curious if anyone knew the tech behind this common issue with aftermarket kill switches--a least a google search seems to show this is a common issue. Never heard a good response as to why it happens. Thanks for responses.
 

·
Registered
Joined
·
5,172 Posts
Alex

The way you are doing it is the way Triumph wired kill switches on 650/750 twins from 1971, an interrupt between the ignition switch and coils. On pre 71's they grounded the points but if I remember you no longer are running points.. Another switch you could use would be the style used on most Japanese bike up to the mid 80's anyway. Yamaha models come to mind as I was working at a Triumph/Yamaha dealer at the time. By the way you didn't miss much not getting to the New Bike Show Last weekend .

K
 

·
Moderator
Joined
·
6,494 Posts
Hi Alex,

My kill switch works in reverse. When kill switch is off the bike has no spark. When switch is on, meaning flow should be interrupted, I have spark.
Just wondering what causes this.
Confusion? ;)

You've installed it as suggested in post #4 of Kill Switch and Wiring If so, it's "doing exactly what it says on the tin":-

. "When switch is on", the "flow" shouldn't be "interrupted", the switch is connecting together the two wires to it; if one wire is connected to a White wire to the ignition switch and the other wire is connected to the White wire to the Boyer-Bransden Mk.4 e.i., the latter is receiving power (from the battery through the ignition switch) and the bike has a spark. (y)

. Otoh, "When kill switch is off", there isn't a spark, because the two switch wires aren't connected, and therefore neither is the e.i. to the ignition switch or battery. (y)

Normally closed means the two wire are shorted all the time, in essence killing the ignition. You should have gotten a normally open switch. Then you would have to press the switch to short the ignition to ground.
One other way to do it is to have the switch earth the coil when pressed.
Regrettably, Alex didn't link the information or his thread that I've linked. As his bike has an e.i., all of the above either won't work, will cause a short-circuit or will bugger the e.i. :oops:

Hth.

Regards,
 

·
Moderator
Joined
·
6,494 Posts
Hi K,

The way you are doing it is the way Triumph wired kill switches on 650/750 twins from 1971, an interrupt between the ignition switch and coils.
Aside, '68-on, when the kill switch actually disappeared from the wiring diagrams. '68 was the the first year C versions didn't have ET and, although the kill button continued to be illustrated/listed with other C-version parts '68-'70, it's the two-White-wire push-to-break button that could be fitted to any Triumph the same way I advised Alex in his earlier thread.

On pre 71's they grounded the points
Pre-'68, the kill button is push-to-make and, strictly-speaking. 'grounded' the points side of the coil(s), making an electrical path bypassing the actual points so, even if the points open, the coil doesn't produce an HT spark (as Scott described).

Hth.

Regards,
 

·
Registered
Joined
·
15 Posts
Discussion Starter #12
Ha ha. Well then, with that explanation, I guess I'm good. Thanks Stuart. The way some of these aftermarket switches are labeled "run/off" makes one think there is a problem in the wiring. But like I said, switch works fine. K I'm actually sorry I missed the show. I would've stopped by the Norton table and introduced myself. Thanks
 

·
Moderator
Joined
·
6,494 Posts
Hi Alex,

The way some of these aftermarket switches are labeled "run/off"
That sounds like it's 'open' in the "run" position and 'closed' in the "off" position? If so, it's still possible to use it with an e.i.; however, it has to be connected differently. Not difficult to do, I can advise if you want to change it?

Regards,
 

·
Registered
Joined
·
1,034 Posts
Do you have a LUCAS part number please...

K
Hi Kadutz,
You do not need a different part number, it is a hidden moisture activated feature on all Lucas kill switches.

What I am particularly pleased about is managing to procure some rare NOS stock. This will help no end when I accidentally let some of the original Lucas smoke out.
718571

regards
Peg.
 

·
Registered
Joined
·
5,172 Posts
K I'm actually sorry I missed the show. I would've stopped by the Norton table and introduced myself. Thanks
Well stop by next year if I'm still here I'll be there. Been at that show for the last ,40 years either visiting or working. I normally get there early on Saturday so I can get a good Gimp parking spot. Goes back to many years ago when there were various club sponsored breakfasts. Get in early see the show and get out before the crowds.

For information the attendance had to be down. At 1 pm on Saturday you could move around. No Triumph, KTM, Ducati, MotoGuzzi. Ural was there but I think only because of Randy. The side area where the Clubs usually are was closed and the Club booths were moved to the main area. BMW Owners club was missing. We were in an area with a commercial shop, Japanese Owners Club and Ton Up. Missed seeing Larry from Ton Up as I left at about 2p. Saw him at a Wake in December. Many of the big dealers who are normally there are no longer doing the show. Same with old smaller vendors Walneck pulled out a few years ago. Think Mikey Trikey moved out west for health. There used to be a guy that sold belts and buckles. AMA has abandoned the Circuit. Also missed seeing Cooch he was supposed to be in for the Illinois Freedom Ride booth. Had dinner with him last fall. He was head of Toy's for Tots Chicago Ride for many years. You know the ride you take with 50,000 plus of your closest friends. Outta time now.

K
 
1 - 17 of 17 Posts
Top