GPZ 750 wiring

Put the red meter lead on battery positive and black meter lead on coil red wire (meter set to DCv) crank the engine- anymore than 0.5v indicates a resistance in the coil feed (possibly kill switch, ign switch or wiring) there is a link in my signature that will take you to my fault finding guide. Focus on the section regarding resistance faults 

will the bike run if you use starting fluid?

meaning: will the bike run for a sec

i don't want you to keep the bike run for an extended period of time.

you probably should run a battery tester on the battery.

Wookie58 wrote:

Put the red meter lead on battery positive and black meter lead on coil red wire (meter set to DCv) crank the engine- anymore than 0.5v indicates a resistance in the coil feed (possibly kill switch, ign switch or wiring) there is a link in my signature that will take you to my fault finding guide. Focus on the section regarding resistance faults 

1.5v between the two, so this seems like it'll be a lot of fun

I've managed to get this to drop to 1.25 by running a wire wheel over the grounds and the connections in the starter button, I have 11v on the output of the starter at crank and it's all the way down to 9 by the time it gets to the starter button

So currently the battery will read 10.5 at crank, I have over 10 at the ign switch yellow, over 10 at the push button in, 9.5 at the black wire out, 9.5 at the y/r on the starter solenoid, over 10 on both main terminals on the starter solenoid. Bypassing the push button I get a little over 10 at the switch but still no go

You may want to check your starter motor after 40+ yrs it may look like this, give it a clean & change the grease for the (planatery) gears could be like concrete
         
good luck

notgoodwithnames wrote:

I've managed to get this to drop to 1.25 by running a wire wheel over the grounds and the connections in the starter button, I have 11v on the output of the starter at crank and it's all the way down to 9 by the time it gets to the starter button

So currently the battery will read 10.5 at crank, I have over 10 at the ign switch yellow, over 10 at the push button in, 9.5 at the black wire out, 9.5 at the y/r on the starter solenoid, over 10 on both main terminals on the starter solenoid. Bypassing the push button I get a little over 10 at the switch but still no go

As this low reading is at the coils, what have you done to resolve ?? If the res of the electrics are working as they should you might consider a by-pass relay (rational and "how to" below)

Ignition by-pass relay W - KZRider Forum - KZRider, KZ, Z1 & Z Motorcycle Enthusiast's Forum

I replaced the starter solenoid and am now getting good spark, it appears that was a rather large voltage drain, the good news is I now appear to be getting good spark, the bad news is now the bike is not pulling good vacuum through the carb again which is odd. The bike will now run for a few moments if I place my hand over the back of the carb to create vacuum then slowly die out after a second or two. Perplexing as I had done a full go through of the carb prior to stripping the bike and it ran great

We're getting somewhere bit by bit. The bike will stay running now but it only wants to run away. I currently have the valve cover ports capped off as well as each carb port individually capped, this setup was fine before but I'm at a bit of a loss as to why I seem to have zero way to regulate air now

When you say you aren't getting good vacuum I think you have it misconstrued. If you aren't getting good vacuum you probably would have problems with your combustion chamber, either being pistons or valves that isnt allowing the engine to suck air in properly. What you describe sounds more like your bike is running lean. If you can put your hand over the back if the carb that means your airbox isnt on? That would certainly make it run lean and hence poorly, describing the conditions you're experiencing. Covering the carb with your hand would restrict air making it rich. With the clean air system removed and all of the ports capped you should have no problem with the way its running if those caps aren't leaking in any way.