[mak68]

I bet if you check all of your harness connections and the Off/Run switch you will find where the break down in voltage is.. Fix that and you wont need the relay.

I went over the connections this past weekend while I was trying to find out why she wouldn't start (turned out to be the starter relay). I decided to check the kill switch, the start button, the clutch safety, and the sidestand safety, power to ignition too, went over the fuses and fusebox as well. Nothing corroded, copper clean. I also did a once over with the multimeter to test the circuits in between these points, it all checked out. The harness wasn't frayed or broken either.
That's not to say you're wrong, it's dropping somewhere, somehow, I just couldn't find drop in the spots I checked.

[DClark]

Wow, made a believer out of me! I thought the voltage drop was from the module.
With your relay and meter, you confirmed that it is the wiring. The wiring in the handlebar area is quite thin, maybe 22g. I measured an even greater voltage gain by handing relays to my headlights.
When all is said and done, you are probably getting a few thousand extra volts to the plugs.
If you are feeling a bit adventerous, you might to to widen the gap on the plugs slightly past spec and see how she does.I have a '06 GTO (has one coil per cylinder) and despite a higher CR than the kat 1100, has a huge spark plug gap, like triple the size when compared to the plugs on my kat 1100 (I don't remember the exact spec, but it looks huge). Obviously, there is something to be gained when you have an ignition that mimics Thor throwing down lightning bolts.
A racer told me that the beauty of a really hot spark is that it makes the engine more tolerant of less than perfect air/fuel mixtures, something that an old carbed bike could benefit from.

[KatKrak]

This Thread delivers!

-G

[suzukiray]

I told you! Ray.

[DClark]

How much voltage does a stock coil put out? I don't think we'll find out. But, I emailed Dynatek and asked them how much their dynacoils put out. They didn't give me the precise answer that I wanted (maybe they don't know???), but here is the response:
"The coil output is directly associated with the output of the ignition, in
relationship with the coil windings. Using the stock ignition, we woiuld
assume it to be around 25 to 32.5k volts at the plug. "

Wow, that doesn't sound like a whole lot!

[stella1100]

this mod really works. I had an 82 kwi 1100 and it ran like crap. I measured the voltage at the coils and was getting 10 on one and only 7 on the other. Did the coil relay thing and it turned into a different bike and started right up. These kats are getting old and corrosion and old wiring makes for more cable loss.

[ian6pot]

Keep in mind you dont need to see corrosion on cables to have a problem.
I work in automotive electrics and see this all the time.The wiring loom is subject to heat and cold and vibration and it will start to induce resistance within the individual cables, even though at first glance the cables look fine.

So to all those who have had the tank off and thought all looks fine, get a volt meter on it and then decide if all is fine.

[DClark]

I don't think age or corrosion is the issue here, I think the size of the wiring is.
When my bike was 8 years old and had just 7K miles or so, I installed relays for the headlight. I don't remember how much voltage I gained, but it was over 1.5v and the difference in light output was amazing.The stock wiring going to the headlight was very thin stuff, that's where the drop in voltage happens.

[DClark]

I just did the relay mod. My bike already has dynacoils and iridium spark plugs. Impressions?
Might be a bit smoother, hard to tell. I took it up a freeway entrance, the one that serves as my official butt dyno , but there was a lot of traffic so the butt dyno was closed.
Although I was a doubter on the first page of this thread and have see no real gains from this, I think it still has promise, I think to see real gains, you'll have to widen the spark plug gap to take advantage of the extra spark. This might take some experimentation. I have found that wide gaps give better low rpm running, but can have problems at high rpms due to spark having trouble arcing.
Unfortunately, I don't have time as the weather has been freakishly warm and nice and I'd rather ride that futz with plugs.
For my setup, I got a $6 relay at Autozone,$5 of red wire at Radio SHack and $4 worth of connectors. For a fuse, I connected the main lead to fuse I use for my headlights ( have relays for that too). I snipped the orange and white coil leads in the front of the engine and simply connected the red power wire to it. Yeah, I know that it is small wire, but it is only about a foot long, and I didn't want to take off the upper fairing and do it direct to the coils. The orange wire that I snipped that is on the right... I connected that as a trigger wire. I put the relay itself behind the battery under the air filter bracket tray, zip tied to another wire.
Yeah, it is rather ghetto, but it took me an hour and it works. I'll clean it it up first snow fall, honest.

edit: For grins and giggles, I went out this morning (42 degrees) to see if the bike would start without the choke. Fired right up! I gave a few twists to the throttle, it responded. It still sounded like it would need the choke cruising down the street, but I bet it would not need to run with it as much. This should help a lot on those sub freezing winter days, prevent spark plug fouling on those cold days I make a run to the donut store.
Oh, with bike running, I measured 14.8v at the battery. With + lead of meter at the coil and - lead of the meter at the - of the battery, I measured 14.5v. This extra voltage, going through my dynacoils is probably giving the plugs an extra 10,000v.

[bob393]

Great thread! I think this is what I need for those sub freezing days.

If I'm reading this right I'm getting the impression that it should help through the entire RPM range with more power because of the anemic stock wiring?
If so I'm sold on that fact alone!

[DClark]

I don't know if I can say I feel it in all parts of the rpm range or even at all.It does seem smoother to the ear, but don't know if butt dyno confirms. I did start the post "why does my bike feel more powerful?" in the katana forum, but can't exactly say it is the coils as I went down to seal level and back, 300 mile rt and it didn't feel more powerful. I look forward to cold weather the plugs won't foul.
One thing I will add is that I really, really, really should widen the spark plug gaps. I have them set on whatever the book says which is pretty damn narrow (speaks volumes about the weak ignition) and I'd be curious to see how the bike responds with more gap. I won't touch the plugs on my bike for awhile though, because:
1) Weather here has been freakishly warm and and I have tried to take advantage of it.
2) Bike sounds like it has a loose valve and I should do a valve check. I am focused on getting a new C14 and will adjust the valves later in winter, that's when I'll pull the plugs anyway.
Oh, the mod took me about one hour to do, cost about $10 for the relay and wire. The wiring job could have been prettier, I'll work on that in the winter too.