1985 GPZ Won't Crank over Won't do anything.

Ok bought this bike for a guy that said just needed a battery and carb clean.

Got the bike home it was late, so put the charger on it the bike cranked. So we left it for the night after taking charger off. Came back a few days later and the bike wouldn't do anything,even after putting new battery on the bike. like the Kill switch was on. Messed with if for a few days and noticed some of the wires were burnt up so replace those wires. Then took kill switch apart to see that somebody sodiered a wire back and that ended up breaking off. So we put it back. So we use a screw driver to jump the starter relay and it will crank the bike over just fine like that.

The bike will crank and crank but not start. We put a little starter fluid into the carbs crank it over and it cranks and almost starts then it will start everyonce in a while for a second and then die. With alot of back fire of course. We made sure the fuel filter was not clogged we checked carbs and they had alot of gas in them. Pulled the spark plugs out make sure they were getting spark which they were and they had some gas on them as well. Really getting down to the bone here and don't know what to do.

The bike is also missing a spring for the kickstand so we leave the kick stand down.

Also now when we plug the gas tank back in the bike says *WARNING* Says the tank is on empty which we know it is not we put 3 gallons in there, and it also now says battery.

When we took the fuel filter out and flipped the tank over it was leaking out of the cap. Could this not be getting a good seal so its not getting a good vacuum?

Any help would be Awsome.

Trying to start the bike while on a charger (or jump starting from a car) is not a good idea as you will fry wiring and maybe other stuff (ask how I know). If the seller said you need a battery you probably do.

If the seller said the carbs need cleaning they probably do. Just because the carbs have fuel doesn't mean they are clean. These bike don't run with funky carbs.

My approach is to eliminate the most likely problems first. I wouldn't keep trying to start the bike until I at least cleaned the carbs and bought a new battery.

Sorry should have been more specific. We did buy a new battery, and we also took carbs apart. They looked clean. Looked like somebody cleaned them already thinking that was the problem and it wasn't so they dished the bike off.

clean them again..check for dead coils...bad ignition components...etc..lot's of stuff to check...hope you find the ggremlin..sometimes these bikes are riddled with them

Not sure of the ignition type on that bike,but take a look at it,and make sure you're not 180 degrees out.
Coils wired up properly?

I'm not familier with GPz but could it be valve clearance? Low compression and that bike is not going to want to start.

Sorry I am new to bikes...


How do I check timing on the bike? Also how do I check the clearance? I feel like a retard lol.

Also is there any place I can find a wiring diagram for this thing?

Here's a link for a free manual for your bike:http://www.thesparesnetwork.co.uk/forums/viewtopic.php?t=119
Hope that helps. Remember, an internal combustion engine needs three things to run: 1)Compression 2) Ignition spark 3) Fuel
If any one of these is missing and/or is out of whack the engine will not run. An easy way to check for compression is to remove a spark plug, place your thumb over the spark plug hole in the cylinder so that it makes an airtight seal, crank the motor over. If the air pressure generated by the movement of the piston is enough to blow your thumb off the hole then you should have enough compression to run.
Start with the simple first:
Be sure your spark plugs are good. I had a similar problem with a single cylinder 175 2-stroke enduro that had spark, but it was weak. Every once in a while it would kinda start, but just as quickly it died. As soon as I replaced the plug it it fired right up.

If your plugs are good, Your battery's charged, your compression is decent, and you know("plugs are wet") it is getting fuel then:

Judging by your description ( occasionally runs for a second with a "lot of backfire"), then dies, I think your ignition timing could be 180 degrees off. This would cause your plugs to fire out of time to the cylinders. Normally I'd tell you to swap the coil wires to the igniter box to flip the timing but since your coils connect to the igniter box with a 4 pin connector, there's no way to hook it up backwards which would cause the plugs to fire 180 degrees off( unless, of course, your wiring is rigged, but since I can't see your bike, there's no way for me to tell). So you could try swapping the coil spark plug wires' position (or alternatively, you could try flipping the ignition advance mechanism, which for some reason, I find too hard to explain how to do). On my '77 KZ 650 the cylinders are numbered 1-4 from left to right, the right coil fires cylinders 1+4, and the left fires 2+3. Your motor should be similar to mine, so the arrangement should be the same. Number your coil wires as they are connected now. Now try switching the plug wires so the right coil fires cylinders 2+3, and the left coil fires cylinders 1+4. Remove the coils from the frame if necessary. Be sure the wires are swapped perfectly. Now try starting her. If it starts, then congratulations, you've found the problem. If it doesn't, be sure you return the coils to their original placement and keep troubleshooting.
If you've ruled out a lack of fuel or compression, then I'd say you have an ignition problem. You'll have to go step-by-step and check your wiring for shorts, burnt fuses, or bad switches (which I kind of doubt since you claim to have spark), and once that is ruled out you can start checking components- your coils, igniter box, and pulser coils. You'll need a manual and a cheap multimeter (Harbor Freight sells on for $7.99)to test your components.
Now there is one thing I forgot to mention, and that is cam timing. Now I'm thinking that if you've got decent compression and the motor turns over reasonably well without bending the valves or damaging the pistons (which should be obvious!), the cam timing should be right, but this is one area I lack in experience, maybe someone else can help you out here. But I do know that in order to check your cam timing you will need to take your valve and ignition covers off and follow the procedure listed in your manual which usually involves lining up the timing marks on the cam chain sprockets with the top of the cylinder head with the 1 and 4 pistons at TDC.


I hope I've been able to help. Whatever you do, don't give up! Sometimes it can take quite a while to fix your bike, (it took me a lot of time, frustration, and some serious headscratching to bring my dead KZ 650 back to life- I ended up replacing my electronic ignition system, and now it runs great) but if you're willing to be patient and to troubleshoot logically, you will succeed!
Good luck!