GPz 900 problems

Having issues with my 85 GPz900.

One day it will start and ride to work and home again with no problems,

But tommorrow it will start and operate beautifully for about 15 minutes

then it starts cutting in and out, tach needle bouncing around then

the engine dies. Motor will then turn over but no go. Feels electrical.

Would the side stand switch cause this or maybe a relay/ fuse, or maybe

the cdi box?

thanks

could be all of the above, eliminate them 1 by 1, start by cable tying the side stand switch pin shut, i think glen has a dodgy cdi connection on his zrx that has cuased alot of trouble.

does it mess around if left on the side stand at idle, if it's does prob not the side stand switch.

good luck sorry i couldn't be more helpful.

Follow the main earth lead from the battery -ve terminal, to where it bolts into the motor. Undo this bolt, give it a good scrub, spray some wizards piss into the threaded hole, screw the bolt in and out a couple of times - give the terminal at this end a really good scrub with some steel wool - then bolt it all up again.

This will eliminate one of the biggest problems with GPz900's electrical issues. If this works - great. If not, then you may have an alternator that is on the way out.

Do you have a multimeter to test the voltage across the battery terminals when the bike is turned off, and then running ?

Have to get the 900 home today to check some things. Already pulled all wiring conectors
apart and put back together to clean them after previous episode. Have to admit have not checked voltage at
battery when it starts jumping around but had checked volts with on board tach/volt gauge
about a minute before it done it yesterday. Gauge showing 14.

Battery seems fine, motor turns over nicely on starter after it stops, just no vroom vroom. If the bike does go leaving it idling with side stand down doesn't seem to worry it. Its just when your 2 or 3 km down the road
it bucks a few times at first like your turning the switch on and off then gets worse till it dies. Its not the running out of fuel type dropping cylinders stop, its the on off throw you over the bars and snap the chain type. Not really trusting it at the moment, last two times i've used it i ended up pushing. Not fun, at least the XS650 is getting some use, although i do enjoy the GPz

Took tank off yesterday and checked fuel tap for operation, works. Rigged up small tank to start bike so i could get to coils and cdi while its running. 900 started[ of cause] and idled on center stand for about 10 min the died. Hooked timing light to spark plug, turned motor over on starter and no spark. Checked connections, side stand but still no joy. Wondered around for about 10 min came back turned it over and hey presto spark. Ran another 1 min and died, no spark.
Did note the igniter box has a Mitsubishi insignia on it, typical, is the box able to be disassembled and inspected for faults, or does anyone know how to repair them.

i don't know how to inspect it myself but this guy does change overs, i have used him before for a cdi and a pick up coil in the stator.

http://www.bettabikes.com/services.html

give the cdi a few taps when it does it, may come back for a minute, good luck.

.....Did note the igniter box has a Mitsubishi insignia on it, typical, is the box able to be disassembled and inspected for faults, or does anyone know how to repair them. ......

If you do manage to get the Igniter box repaired, can you bung up the details here ?

I had a very similiar problem with the Igniter box on my '83 GPz1100 - it also had some weird issues with running & starting. All fixed when I changed the igniter box to a spare one. The '83 1100 uses a Mitsi igniter as well, I think it is the same one as your 900R and also the 1000RX from 86/87 ?

I have never taken one of these apart...........but its only a matter of time

Well don't have to worry about fixing ignitor box, its not the problem. Changed it, entire fuse panel and side stand switch and it still doing it...... .
Checked, cleaned tightened all wiring connectors and earth leads, checked clutch, stop and ignition switch for operation, but still no joy.
Measured air gap on pickup coils, fine.
Unless its the pickups somehow failing together, i'm just out.
Think its time to take it to the kwaka dealer, i'm Spent.......

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For $40 go buy some new leads and give that a try.
Mine had pots missing and poor power, massive flat spots.
New leads, plugs and a carbie balance and all is good.

except for the effing rain....

Fixed it, finally.

Pickup coils where the problem, don't ask why both where failing at same time, as
I don't know. Changed them yesterday and went around the block with no problems,
so today with weather a bit better went a bit further and made it home.

After changing ignitor, side stand switch, fuse panel, trimming the ends of
the spark plug leads and new plugs there wasn't much left.

Found Ron Sullivan very helpful, just over the border at Murwillumbah and
parts very reasonablly priced,[ not like some]. I recomend if you require parts
for your 900 email him with a request, you can get him at crystalcreek@internode.on.net

good to hear you have sorted out the problem I emailed Ron the other night about some GPz1000RX parts, but he has already sold all the fairing panels but he did get back to me really quickly so that is always a good sign.

isnt it funny how the last thing you try is always the problem glad to hear your mobile again.I also have delt with Ron through ebay and found his service very acceptable