Some of you may have seen my thread trying to troubleshoot my bikes unwillingness to make spark and rev last weekend. The ECU was blamed when we swapped one on another to test and the spark seemed to respond better (using a timing light), even though it was still acting like it had a fuel issue. I got another ECU and took it to the shop this morning and he went to work on it. I dropped by after I got off work and heard the oohhhh so smoooth sound of my motor running just like it should.

The conversation that followed is the really confuddling part. My replacement ECU changed nothing. He spent the entire afternoon going through the wiring and testing everything from the signal generator up the wiring to the ECU. Except when he stuck a test light into the green/white wire that runs to the signal generator the bike smoothed out. Purred. Never would have suspected a thing was wrong. So he made up a ground wire and tried to replicate it, nothing. Then I showed up and we rummaged around the shop and put a couple different lightbulbs in there to give it some resistance, but it didn't work. So we took apart his light and tested the bulb inside it and got 30ohms of resistance. We found another bulb just like it and wired it up to run some resistance against that green and white wire and the bike acts like it's a virgin. Damned if we know why.

So anyway, the bike runs now. Obviously this is nothing more than a temporary fix, but I was wondering what on earth could cause interference that would only be resolved by adding resistance to that wire? I'm planning on buying new generators and the wiring that goes along with them so I replace that entire system more or less and see if that doesn't resolve the issue once and for all. My next question is, do you think I'm going to fry anything running it with my ghetto resistor for a few days until I get parts to fix it next week?

What's the wire labeled as in the manual?

Its still sitting at the shop so I can't check, but it runs from pickup towards the forward of the bike, to the plug on the igniter. The green and white one. So its just one of the signal wires. 

Told ya she's a temperamental b!tch. 
Sounds like something with the Veypor.  It's tied into one of the coils to read RPM.  Maybe the added resistance is helping to balance the circuit.  I dunno. 

Using a lamp bulb as a resistor; bright idea.

prs

http://www.gs500e.co.uk/wire.jpg
http://img.photobucket.com/albums/v300/tdan553527/Page26.jpg

Here are two diagrams. I still have to look at them myself but, I figured I should post em first.

Doesn't the tech have ohm specs for the parts of the signal generator? I would think something is wrong there. You said he tested everything FROM the signal generator TO the ecu (which you replaced) but did he check the generator itself. I don't know the part very well but it reminds me of my crank position sensor mounted INSIDE the distributor on my 84 Pulsar (thing got a little too warm being mounted to the engine and all). I see the older ones had three wires and the newer ones, 04+, have only two wires??? Is one constant voltage and one switched.
If it wasn't obvious, I wasn't YELLING, just placing emphasis. I suppose I could underline...   

I have the wiring diagram, tracing the wire is not the issue, knowing the cause of the interference is. The veypor pulls its signal from the wire that runs to both pick-ups, so it shouldnt affect this wire. Also, the veypor was on the bike for a while before this issue started up, so its a possible culprit but I'm doubtful.

I'm hedging my bets on the pick-ups starting to go out, so I'm going to replace them and see what happens.

The wiring in this thing is a mess, put nicely. You can buy harnesses all day long for $60 on eBay. I think when I park the bike for the winter I'll make brackets to hold the relays and run fresh, new, clean and uncut wiring. Its just a nice touch to have everything look like it was built that way. Having a rats nest usually doesn't scare me too bad, but now that she's decided to form some wiring problems I'm seeing the value in a good clean harness.

Sounds like you could use a new harness but will that fix it?

A new harness is just for posterity's sake.

This particular issue is centralized in the signal generator/igniter system. Which includes the ECU/Igniter box, the coil packs, the spark plugs, and the pick up rotor. I know the ECU is good, having done a swap test (I now have an extra ECU), I know the coils are good, I know the plugs are good, so providing that there is no interference from another system, and I don't *think* there is, replacing the pick-ups and their wires should fix this issue, just because they are the only piece of the puzzle that I can't prove are good, so the must be the cause of the problem.

I've got requests for pick ups out in the classifieds section, hopefully I'll find a set shortly and when I get back in there I'll trace every wire of this particular system and make sure there is no interference, or a short or a bad ground. The mechanic has picked through it pretty meticulously and didnt find anything, so I'm pretty sure I won't but its worth the time.

Ask the mechanic about the technical service manual, if suzuki put one out, which they should have, it should contain resistance values for just about anything that needs measuring. Somewhere in that system something is out, obviously, and it should show up on a meter. Is it a suzuki dealer your going to?