Help...bike won't start! II

[jawise1980]

Hello all.
Ok...It's a '91 kat 750. There is a bad ground or an exposed wire somewhere around the tank. I've figured that much out. What I can't figure out is where that exposed/poorly grounded wire is. I've checked all the wires around the bike. Damn things naked as the day it was born.
The bike is dead right now. I get a neutral light sometimes when I have the tank elevated off the frame, but that doesn't help at all. That has just led me to believe that the wire in question is around the tank. When I do get that chance connection, it starts and runs fine, but we all know that the tank needs to be connected to the frame. So, I reconnect the tank, and the neutral light goes away. Tank touches frame when I have it lifted off and away from it's resting point, and thats when I achieve that spark/connection.
God does not want me to ride right now. It's been a week and a half or so, and it's getting very tempting to get my wallet lightened at the mechanics. I have the money, but DO NOT want to give it to them.
Any advice would be appreciated. Thanks in advance.
Jimmy

[md86]

You sure the tank isn't touching any bare wire when it's on , like say from the wires near the coils ?

[The CyberPoet]

From the sounds of it, the negative wire between the battery and the frame is corroded and providing excess resistance -- either at the battery, at the other end where it mounts, or under the insulation for the wire itself. The gas tank is not a critical part of the grounding scheme and in fact should not have any electricity running through it's exterior as a ground path or otherwise.

The second most likely candidate is under the wrapped wires that run along the right side of the bike towards the instruments and controls at the handlebars, in which case the problem probably lies in that bundle right where it goes by the right side of the valve covers. That bundle is prone to abrasion by vibration is not strapped down well, including wire-on-wire abrasion inside the bundle under the electrical tape wrap.

I hate wiring problems of this nature on old bikes, because the only good way to fix them properly is to simple start rewiring (replacing entire lengths of wire from end-to-end one at a time). An ohm-meter would also help you at this point, so you can measure wire runs before you both to replace them -- the resistance should be 0.0 to 0.01 on virtually any wire (continuity tone on most ohm meters); higher means it's time to replace the wire or that you didn't diconnect it at all the connections before measuring.

Good Luck!
=-= The CyberPoet

[jawise1980]

Update

Alright.
We are now going through all the wires testing the continuity. As we were starting out on this, we noticed that there was a bad connection at the point where the positive wire from the battery connects to the starter solenoid. When we jiggled it around, the neutral and oil lights would go in and out. So, that has been 'pinned down'. The headlight and taillight are still out, so we will begin checking those wires, accordingly.
I'm replacing some of the connectors, as they have become corroded or melted. I am constantly reminded of how old this bike is. Almost all of the wires have some questionable areas and will take a long time to check. Good news...The solenoid is good/operational.
Anyways...Back to the grind. I will keep you guys posted on any further advances. Thanks for the replies.
Jimmy

[The CyberPoet]

Electrical cleaner (spray), a stiff nylon bristle tooth brush, a bit of emory cloth (super fine grit) and dielectric grease is your friend. Any connector your find, spray it out, check it closely, brush or sand contacts as appropriate, and spray again, then slather with dielectric grease. It will keep future corrosion from forming in there (won't stop corrosion that already started -- if you find any, replacement time, or it'll spread down the wire over time).

Best of Luck!

Cheers,
=-= The CyberPoet