ignition coil relay mod

[LGR]

Thanks for the info on the ignition coil relay mod the bike has never run better and I bought it new in 1982.
I was able to buy a 5 lug Bosch relay (only use 4 lugs) and the pig tail/gang plug at my local automotive.
I ended up mounting it to the left hand sidecover frame lug with a piece of 3/4" rubber hose and 2 bolts this kept the wiring short and simple.

[LGR]

here's a side shot

[Steve]

Nice to see that your Band-Aid is working well.

It's still better to find where your voltage drops are and fix them, but this will keep you going until then.

It's possible that your voltage drops were early in the system, which means that your lights might be getting lower voltage, too.

.

[elevatorman71]

dumb question only because i havent done it myself yet. what are the positives in doing this ignition coil relay mod?

[bonanzadave]

Nice to see that your Band-Aid is working well.

So youre not a big fan of the Relay Mod ? Ive tried to reduce the voltage drops from the + Batt post, fuse box, connectors, switches with electrical contact cleaner.... the next thing would be the old wire harness. Increased resistance in the old wires.

[LGR]

dumb question only because i havent done it myself yet. what are the positives in doing this ignition coil relay mod?

It bypasses the huge loop of wire and switches that makes up the stock positive + ignition coil circuit and allows you to increase the wire size as well. My bike had 10.2 V at the coils with 12.2 at the battery now with the relay and larger wire that has a more direct path to the battery it has 12.0V.
A few years ago I had a no rev situation it stopped at about 3000rpm, just sounded like a rev limiter no back firing, nothing to really indicate it was anything obvious. I took the carbs apart, cleaned them no change, popped the rocker cover off to see if the cam chain had jumped any teeth and it hadn't. I had already checked earlier that it was firing on all cylinders. So after 2 days of checking everything it turned out to be the clutch lock out switch,(you have to pull in the clutch to start the bike) not sure if that just applies to Canadian bikes in 1982 or it applies to the US too. Anyway the switch was making bad contact, and the contacts were vibrating with the engine rpm.
So I bypassed the switch, but that still leaves the 30 year old ignition switch and the kill switch for the coil power to go through not to mention about 10 ft or so of minimally sized 18g wire.
Anyway always use a little dielectric grease on all your conections, I like Grote over the silicone based variety although it won't take the heat for spark plug caps.

I told a friend of mine how well the relay mod worked on my bike and suggested he try it on his 70's vintage cb350 Honda and he laughed because a few years ago he had a starting problem with his John Deer garden tractor and some one was selling a relay kit online to solve the problem, apparently they have a lock out switch for the clutch and seat and too much wire as well, anyway he bought it installed it and it's never failed to start since.

[elevatorman71]

who has the origional thread with directions?

[LGR]

who has the origional thread with directions?

this should help