The Silent Killer (Switch)

[mashermoto]

Burge, how far can you shoot a pellet

[tomterrific]

Everyone should be aware that kill switches on old motorcycles are a huge cause of breakdowns. I brokedown twice last year, once on my old XS which I am sorting and once on the old Triumph which is my long time rider. In both cases the kill switch was responsible. The Yam's switch was totally buggered and the Bonnie's harness pin connector had burned. In the case of the Bonnie I was coming back from Mid-Ohio and the bike died. I found a piece of wire beside the road and jumped the ignition, battery to coil. I returned home and rode the bike like that for a while until I fixed the harness. I put a little jumper in the kill switch in the Yam and rode it around until this winter when I decided to creak open the purse and $45 later I have a new hadle bar switch control from Mike's.

Tom

[pamcopete]

tomterrific

The following little mod will prepare you for a failure of the kill switch and get you home. It also works if you blow the fuse on single fuse bikes.

1. Connected an inline fuse holder between the ignition coil and the battery. Locate the fuse holder underneath the seat.
2. Put a blown fuse in the holder. (To keep the contacts from touching)
3. When the kill switch fails, or the main fuse blows, lift the seat, put a good fuse (10 A) in the holder and ride on home.
4. Do not operate the kill switch with a blown fuse as that will "back feed" the short and blow this fuse as well.

[eric123]

Good tip pamcopete

[tomterrific]

I just string a wire in there when it happens. It'll never happen again, right? ;^) Actually what I do is keep a jumper wire with alligators in my tool kit. I can use that wire to jump around lots of bad electrics.

I should fuse the jumper I guess, or a small resetable circuit breaker would be ideal.

Tom

[slide]

I eliminated my kill switch due to numberous bad experienes on other bikes, especially my Harley. On long trips I often ride with a trottle control to relieve wrist fatigue and often found myself inadvertantly shutting off the kill switch when moving my hands to a different position on the bars. Coast for awile until you realize what you did, and then, KABOOM when you turn it back on. Backfires at 90 mph are not nice. If the trottle sticks, pull in the clutch. Sometimes I think motorcycle riders would be far better off if they learned to ride on the older bikes that did not have all the gizmos and rather ride by relying on their skill and witts. That was just my $0.02 worth.

[pamcopete]

slide
I also try to be prepared to grab the clutch for any bad engine problem, even if it means overreving the engine with a stuck throttle. I still like to have the kill switch available so I can then shut the engine off if it hasn't self destructed yet, but in any case, you may want to retain the kill switch for insurance reasons and it case someone else rides your bike, or if you sell it. My little fuse / jumper mod also takes care of an open key switch or even a lost key (I used it once for that) . I keep the seat key in my wallet.

[crazypj22]

I just lube throttle cable to prevent sticking. ;D
Did have one freeze open once several years ago.
Was an old bike that didn't have a kill switch (around December 1975)
I'm still here so it couldnt have been serious ;D
PJ

[pamcopete]

The Cure

To eliminate the drop across the "Kill" switch and the "Key" switch, I installed a relay that provides a direct connection to the battery for the ignition coils. The relay is available at most auto supply stores and is normally used to power up auxiliary lights. It is rated at 30 Amps. Mounts on the mounting bolt of one of the coils.

[Six-Five-O]

Hey Pete...Do you have a brand and part number of the relay you used?

Thanks

John

BTW...I've stickyed this thread ;D

[pamcopete]

Six Five O

Here is a pic of the one that I use. These are generic relays made by a number of manufactures and usually displayed in the fuse and light bulb section of most auto parts stores. They are about the size of an ice cube and come with a mounting tab. They sell for about $5. You can also go to www.wiringproducts.com and look for their part # R-40AT for $5.95 plus shipping. This is a 40 Amp version of the same relay. The advantage of these relays is that the contacts are made from a semi precious metal that lasts longer and is more resistant to pitting. It's like getting a brand new ignition switch for $5.

[pamcopete]

Here is a graph of the performance difference between the "killer switch"/ "key" switch contacts and the relay.



A stock points coil is 3.9 ohms and a stock TCI coil is 2.5 ohms

[mkrusz]

pamcopete said:

Brotherhood of JB Weld Fixes Everything

Well, at least you will get more current to the coils without the "kill" switch. Got to get your priorities straight.

Go to Mikesxs.com and purchase a new switch and get a AGM battery.

Cheers, Spock

[pamcopete]

spock
Well, the ignition switch from Mikes is $28 and he doesn't list one for pre "late" '78 models. The bar switch with the kill switch goes for $46. (Free shipping! ) The problem has nothing to do with the battery. , but if you insist, an AGM battery costs $59. You should still clean the contacts on both switches if you are not going to replace them. I like the $5 ;D relay idea which bypasses both switches to the coils.

[mizadventure]

just wanted to chime in on the usefulness of pamcopete relay/inline fuse mod. w/ his kind assistance, I wired in the relay to deal w/ the voltage drop I was getting across my main switch & I'm darn happy w/ the result. no problems firing up and nice having the peace of mind that if I blow the main fuse (as if that would ever happen, right?) I can still get the b