[Patch's]

I know what your saying about the increase in voltage and as you see I measured with 13.66, look at it this way the fuse box is behaving like a bottle neck - that will not change the voltage will rise as the generator increases output but it will not eliminate the the loss. When the bike is in the on position but not running there 10.75v (at the ready) at the coils and the ignitor no load the engine is not turning yet the battery has 12.2v (no charging). What I am saying is that I can get just shy of 12v at the coil if I remove the lights again showing it's not the gauge of the wire but loss at the fuse box!

You can divide the circuit into individual components which I did and still only get 10.75 so you can't say it's the wire size at the coil when that is what I measured at the ignitor!
As for the rest I agree the light mod I read you built and the coil mod is a very good fix so long as when the relay shorts it has full battery voltage output which means take the source before the fuse box.
I checked the residence and found no obvious faults every where in the loop.

[DClark]

If what you are saying is true, I would have gotten more than 10v of juice out of the head light harness- I did not. Hooked up relays with 12g wire, now get over 12v (maybe 13, don't remember). I saw the same result on my '96 Impala SS and my '03 Jetta- used relays to get more voltage to the headlights.
On the Katana, I never played around with taking the headlights out to see if there was a change in voltage because frankly, it would be irrelevent. Headights on with stock wiring, coils get around 10v, headlights on with relays, coils get over 12v, looks like a no brainer to me.
That wiring is small enough to cause a voltage drop, that's a fact. That's why home and car stereos should be run with run with at least 14g wire (12g is better).
You can even measure it yourself, connect a 20' length of 24 g wire connected to the battery, then measure a 6' length of 12g wire connected to the battery.

[Patch's]

I understand voltage loss and understand well enough ohms law, I am agreeing with the mods, I just wanted to know where, why and what was causing the loss, if it had turned out that I was measuring the loss in the loop because of the orange/white wire then I would just replace it but that is not the case, do you need a 12guage wire for 4 feet to deliver 4 or 5 Amps I don't think so but it want hurt, if you took the power for your relay setup after the fuse box then my guess is you will repeat the problem, take it from the battery or starter solenoid then you beat the problem and only compete for power with the starter for the 10 or 15 seconds.

[Kreylyn]

The Ninja 250 (88-07 anyways I know) does not turn the headlight on when you turn the key on. It won't turn on until the engine is turned over, and then stays on until the key is turned off.

I think I'll look into how that is happening and see if it's something that can be applied with a light relay mod on the Kats.

Krey

[Black Phoenix]

what sort of issues may come up with having a wider gap? just the possibility that it wont arc?
would this wider gap also work on a post 750?

[DClark]

what sort of issues may come up with having a wider gap? just the possibility that it wont arc?
would this wider gap also work on a post 750?

Yup, won't spark. It just won't be able to make the leap. The bike could have a fine idle, but when you get into the higher rpm range, it will be flat, might sputter too.
A wider gap will help any of these bikes, just make sure that you have the juice to do it. It is kind of like those motorcycle riders that do jumps- if they don't have the power, they don't make it.

[Patch's]

voltage loss mod at/for coils

Hi guys it has been 4 years since this post and I just wanted to add to it. I did mod the circuit at that time- but was spent trying to explain it; here is what I did and how reliable a fix it has proven to be over the years.
Simply put and as I mentioned early on in the post, the fuse box bus was the problem! I also had the same issue on another Suzi monster from the same era which provided me with the ambition to solve this!

It was this simple a fix: I cut the harness plug off at the fuse box-
I opened the up to gain access to the wires-
I crimped female connectors to each fusible circuit-
I dropped the accessory one at the bottom of the box (never used it)-
I bought a new different box at a local supply for $6.00 with 6 circuits-
The box was only ½” thick by 3 ½’ so I placed it right under the seat front
securing it to the tank bracket-
I ran the same main power circuit R/W wire to the new box bus.
That's it!

When we got the bike it could be a real pain to start, also I had found on occasion only 8V at the coils after hard starting attempts! When that would accrue (after many cranking attempts) I would read 11.7V ish; at the battery; I wrote that off as a overheated circuit because, the coils draw little amperage. So I concluded that the problem being- when extended cranking accrued the old circuits would heat and added to the loss I mentioned in the earlier posts! Add to the long cranking of course she would flood, bloody frustrating!

In addition I ran a 10g new wire to the head lamp connector, direct from the new box rapped to the harness exterior, no splicing right into the original connector!

The results have been solid, wet, cold or hot the bike always impressed as it would start right up even after winter- out door storage.
Total at that time 4 circuits just like the original with the exception of dropping the acc; the bus made the difference! My total loss across the coil circuit is ½ a volt, all conditions.

The wiring diagram in the manual is very good, easy enough to follow and you only have the wires at the fuse box to refer to. This mod is easy, cost less than $10.00 and the uncertainty has been ruled out.

Just this week we moved and replace the fuse box to accommodate some recent engine work and another mod, which I will right up next week.

stamp reads: build Sept. 1987 GSX 1100F
What an amazing bike, she has proven to be!

Patch

[retcol]

Your intermittent problem could be the spark plug wires and or caps, they can cut out when hot or broken inside the cap. I had a similar problem on a Honda 900 that i thought was coil related, but it wasn't and new wires and caps cleared it up.