Coil relay mod end all thread!!!!

[bonanzadave]

84601 Dorman 4 pin 30 amp 12v relay $6 something

Yep, I used that one for my RR sense wire. I was charging at 16 vdc with duanes RR. I used insulated crimp terminals BTW. The brakelight switch wire for the RR sense was at about 10.9vdc. Did the relay mod and now Im charging a solid 14.5.

I dont really have a problem starting and Im in no hurry to do the coil relay unless someone can tell me that it will help my gas mileage. Im at about 37mpg but back in the day I know I got better than 40mpg.

[don_gibb6512]

I used this relay: http://www.partsexpress.com/pe/showd...number=330-070

with this socket: http://www.partsexpress.com/pe/showd...number=330-075

and it worked great. I must admit, it took me WAY more than the 20 minutes referred to for this. I soldered all my connections and secured the relay mount on the frame, under the gas tank to minimize vibration.

I went from 10.28v at the coils to 12.15v Big difference.

[duaneage]

Anyone else had reliability problems with these relays? I was using a relay to bypass my crusty ignition switch. The first two (Bosch) burnt out in 3 blocks (but worked fine on the centerstand, even at redline). The third (no-name cheapo) burnt out merging onto a freeway but gave 3500 miles of service first. On all three the wire from one of the posts to the coil broke. On all three I was cruising at ~ 3k rpm. I've decided to replace electrical components in the future instead of bypassing them with relays. It was a failure from vibration and shock, not an electrical issue. I had mounted them on zipties tied to the chassis by the battery box. Maybe I just have bad luck.

That is the correct answer. Cars today rely too much on control circuits for ordinary functions, the result can be more problems.

[bonanzadave]

That is the correct answer.

Crap, Ive cleaned and applied grease to every connector on the bike. if I want that brake light wire anywhere near battery voltage Ill have to start replacing the wire harness.

[PAULYBOY]

I put an otherwise expensive Mercedes relay (a universal 4 pole relay with the three pointed star on it) on my 850, and a Pep Boys relay on my son's 450. He's put far more miles on his 2 puffer than I have on my 4 puffer, but thay're both still going, so someone must have gotten a bad batch of relays. Maybe they're the relays with salmonella, or botulism, or some other fatal contamination.....

[NetBSD]

Yep, I used that one for my RR sense wire. I was charging at 16 vdc with duanes RR. I used insulated crimp terminals BTW. The brakelight switch wire for the RR sense was at about 10.9vdc. Did the relay mod and now Im charging a solid 14.5.

I dont really have a problem starting and Im in no hurry to do the coil relay unless someone can tell me that it will help my gas mileage. Im at about 37mpg but back in the day I know I got better than 40mpg.

well i dunno about mileage but with 12v at the coils doesnt it improve the burn of the fuel in the cyl.? so you would have less wasted fuel. this is a ballpark so correct me if im wrong

[p_s]

I put an otherwise expensive Mercedes relay (a universal 4 pole relay with the three pointed star on it) on my 850, and a Pep Boys relay on my son's 450. He's put far more miles on his 2 puffer than I have on my 4 puffer, but thay're both still going, so someone must have gotten a bad batch of relays. Maybe they're the relays with salmonella, or botulism, or some other fatal contamination.....

The first two bad relays could have been from a bad batch--same brand from same store. The 3rd lasted 3k miles and then gave up on an on-ramp.

What I'm looking to hear is:
"I installed a relay 5k miles ago, no problems."
And I still haven't heard it. Motorcycles are a tougher environment for electronics than cars. And all 3 failures were at low RPMs on good roads.

I'm still waiting on a new ignition switch and I've hotwired the bike. The Suzuki of America buggies should be crossing the continental divide any day now with my parts. If I didn't have to ride on urban freeways I'd put in another cheapo relay for convenience until my NOS ignition switch arrives.

[duaneage]

Crap, Ive cleaned and applied grease to every connector on the bike. if I want that brake light wire anywhere near battery voltage Ill have to start replacing the wire harness.

The way to determine where it is being lost is with voltage drop tests across components. measure across switches and connectors and when you find 0 volts of drop, that is a good connection. Greater than 1 and it's suspect. Over 3 and it is going to get hot and melt something.

The relay may get around a low voltage condition at the end device but that resistance elsewhere is going to heat a connection and cause a problem.

What does higher voltage at a coil do? It does not change the spark heat or fire very much but what it does do is raise the recovery rate of the coil. Higher voltage across a coil increases the saturation level of the system and permits a faster cycle than lower voltage. In other words the spark is more reliable at higher speeds.

I used a second battery wired to a switch on one of my hotrod cars to increase the coil voltage to 24 volts when the throttle was wide open. Since it was only for a few seconds the coil was not damaged ever, but the engine saw 7000 rpm easily. When the throttle released the battery went back on the electrical system and recharged. Knocked another .2 off the quarter mile time in blind testing. Those were the days of .90 gallon leaded gasoline and 4 barrel Holley carbs.

[TheCafeKid]

Better question still for the people (person?) whos had them fail after mileage. Were you using the dollar or two more WATERPROOF relay? or just the normal one? Dunno if that could be an issue, but even a lil bit of dew or light rain water, condensation or whatever could have caused a problem.

[p_s]

Better question still for the people (person?) whos had them fail after mileage. Were you using the dollar or two more WATERPROOF relay? or just the normal one? Dunno if that could be an issue, but even a lil bit of dew or light rain water, condensation or whatever could have caused a problem.

I think just the normal one. But I took them apart and all of them had a broken wire from one of the control terminals to the coil, so I think it's the vibes that did it. The first two I mounted fairly rigidly to the frame and they lasted a few blocks. The last one I mounted loosely on a zip tie and it lasted 3k miles then failed at a very inopportune time. Noone else has had any failures, so maybe I did something wrong.

Also my relays were just bypassing the ignition switch. And I have a GS550ES, which is known for having bad vibes at 5k (noted in period reviews) and being smooth everywhere else. I usually avoid 5k, but that could have something to do with it.

[seuadr]

i left mine sitting free for that exact reason.. it's nestled between the airbox snorkle and the frame. when i get a chance, i'll make a double rubber mount for it.

[aruyle79]

what does this mod do exactly for performance? forgive me for being an idiot on this one.

[don_gibb6512]

what does this mod do exactly for performance? forgive me for being an idiot on this one.

Less than 12v to the coil can cause a weak spark and therefore not ignite the compressed gas/air mixture properly or completely. You get a "better bang for your buck" so to speak with 12v at the coil. Weak spark can also manifest itself as fouled plugs over time, which was the problem I was experiencing. I do have a noticeable increase in power in the upper rpm range now too.

HTH

[PAULYBOY]

What kind of rubber mounting options do some of us use? I would use a few things from the mercedes parts bins, specifically, an air cleaner mounting buffer, which is a piece of rubber about the same diamemter as a quarter, about 4 times as thick, with 6mm studs sticking out of each flat side. I'd drill and tap a 6mm hole somewhere, screw it in, put the mounting lug of the relay on the other stud, and use a 6mm locking nut to keep it there. Is that the kind of idea you guys are talking about?

[80GS750]

that would work.

any rubber mounting that will minimize shock will help out.