GPZ500 common issues?

[MikeyBrown]

Hi all,
I'm thinking of buying a '91 GPZ500 with 17k miles on the clock, ready for when I pass my mod2 (one is going cheap in my local area so I thought I'd pick it up if it's worth having)

I was just wondering if there are any common traits and/or problems with GPZ500s of this age? Are there any parts in particular I should check over before buying it? (other than the basic bike-buying checks)

Thanks in advance
MikeyBrown
____________________
Past Bikes: '97 CG125, '91 GPZ500S, '01 FZS600, '07 S/Triple, '99 ZX9R, '82 GP125, '83 GP100, '03 SV1000S, '98 ZX6R
Current Bike: '07 FZ1N
Trackdays: Darley Moor - 15/6/12, Donington - 28/8/12

[gfiandy]

Hi,

GPZ500 is a tough bike but it does have a few weaker points:-

Exhaust down pipes rust - If they havent been changed check them they will probably need to be replaced soon. Check the balance pipe underneath as this is often the first part to go.

The swing arm bearings wear, unlikley at 17K but it is possible.

If oil changes have been ignored the CAMs could be worn but this is unlikley. They should be good for 50K. The engine always sounds a bit rough but if it doesn't pull well this could be the problem.

The frame and swing arm rust this rarely becomes bad enough to cause problems but worth checking.

The paint on the engine tends to lift off, doesn't cause any problem just looks unsightly.

I think this year is the earlier type with the 16 inch front wheel this is a bit quicker turning and slightly lighter in feel than the 17inch (I have had both) but it becomes a bit twitchy on worn rubber and the bars tend to shake; so if the fronts near the limit recon on replacing it. You don't want to be dealing with a twitchy front end whilst you learn.

Faring tends to crack arround the front indicators. (Usually because it has been dropped.)

Front brake is barely up to the job. If you find its a problem fit good brake pads (EBC green stuff) and a braided hose. If this hasn't already been done.

Rear brake on earlier bikes is a drum, the drum sometimes goes out of shape or cracks internally. If its bad you may feel it as pulsing on the brake pedal.

Don't be put off by this list, all bikes have problems and you probably won't find any of them. An excellent choice of first bike.

Regards,
Andrew
____________________
ANDY

[MikeyBrown]

[Dazbo666]

I had the '91 GPZ500 as my first bike, and I dealt with a few of the problems mentioned, but learned LOADS in the 2-3 years that I was riding it...

Did a temporary fix on the exhaust balance pipe until I could afford the s/s replacements.
I also upgraded the front brake line to Goodridge braided
The main headache was at tyre changing time... mainly because of the 16 inch wheels, the choices were limited, and so was the stock at local dealerships. (Bridgestone BT45's recommended for summer and winter riding).
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1st bike (Sept'06 - May'10) : 1991 GPZ500S / Current bike (since Nov 2009) : 2003 Suzuki Bandit 600N
Word of the day : DILLIGAF

[Glenben92]

Rear shock is a weak spot, i've heard.
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57 Huoniao HN125-8 - , 97 Kawasaki GPZ500S -
99 Yamaha FZS 600 -
Mod 2 Passed - 01/10/2010

[gfiandy]

They are not hard to get but I don't think there are many options.

I always used BT45s and found them good but make sure you keep the pressures right or they pocket (wear just either side of the center line) which doesn't help their performance or life. (Most pressure guages on pumps over read by at least 2psi so its worth getting an accurate pressure guage.)

I think its a 100 / 90 16 if I remember right.


Bridgestone Bike Tyre 100/90H16 BS BT45 F TL 100 x 90 x 16 £61.08 £12.22 £73.30
Metzeler Bike Tyre 100/90H16 ME LASERTEC F TL 100 x 90 x 16 £66.00 £13.20 £79.20
Pirelli Bike Tyre 100/90H16 PI SPORT DEMON F TL 100 x 90 x 16 £67.20 £13.44 £80.64
Avon Bike Tyre 100/90V16 AV ROADRIDER F TL 100 x 90 x 16 £68.76 £13.75 £82.51

These appear to be the options. I have only ever used the BT45 as it is the origonal fitment and the prices are all about the same.

Regards,
Andrew
____________________
ANDY

[stinkwheel]

That model has a problem the glue that holds the alternator magnets on.

There is a risk that a magnet could drop off, hitting the moving alternator rotor and taking it out along with the ignition pickup coils while contamiunating the oil with magnetic dust.

This is a messy failure if it happens. it's not terribly common but common enough to make it worth looking for a later model if you can.

Post '94 models do not have this problem.

A lot would depend on price. If it's good and cheap, you can take a gamble. I've had both models and found the earlier one to handle slightly better and it seemed a trifle pokier (may just have been my one though). The drum rear brake is considerably better than the rear disc on the newer model.

Standard exhausts rot very quickly. They eventually go under the bit of trim where the pipe meets the silencer can and that's them screwed. If I was buying second hand, I'd be looking for one with an aftermarket exhaust already fitted (or budgeting for one). Motad Nexxus pipes work well on them.

The starter solenoid has let go on all three kawasaki 500 twins I've owned, the ignition switch has also packed in. Not expensive to replace though.

The plastic unitrak bushes are loose from day 1 leaving some vertical play on the swingarm. This can lead to an MOT fail if the tester isn't aware of the problem (if they know about it because they've fitted new ones themselves in the past, they are inclined to give a bit of leeway), I've had to wrap the pins in PVC tape to get them through the MOT before today. The other option is to remove the mainstand before the test which makes it almost impossable to check.

On old models, the flashers are rigidly mounted to the fairing. If it's been dropped, they'll punch a hole out of the fairing round the mount. Check round this area for repairs. The newer model has flexible rubber mounts.

They are a good first bike. Plenty of go about them if you keep the revs up, very frugal on fuel if you don't. Pretty cheap to maintain too as compared to a 600 IL4.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Kickstart]

Hi

Big problem is the magnets on the flywheel coming off. Seem to last 20k~25k before they fail, and when they fail they can take out the stator as well.

Suspension linkage bushes are knackered from new . Seriously, brand new bushes had enough play on ours that some MOT stations would get arsey over them.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[MikeyBrown]

Thank you for your advice on these gpzs. The problems that have been named with the alternator, can they be noticed just by checking the alternator? Do they make a noise or...? And can the problem be rectified before it goes wrong?

And the swingarm havi play in it, again is there anything permanent you can do to change it, or would i just have to bodge it for the mot?

Also, would you actually recommend this model of gpz, bearing in mind the price i have been offered it for?

Thanks again,
MikeyBrown
____________________
Past Bikes: '97 CG125, '91 GPZ500S, '01 FZS600, '07 S/Triple, '99 ZX9R, '82 GP125, '83 GP100, '03 SV1000S, '98 ZX6R
Current Bike: '07 FZ1N
Trackdays: Darley Moor - 15/6/12, Donington - 28/8/12

[Kickstart]

Hi

You can take the alternator cover off and check manually, but not sure how much warning you would get. Unlikely it will give any warning by noise or other signs. We had had them fail twice. First just refused to crank over occasionally for a few days first (put in gear and push it forward and it would then crank over).

The other just had no charging ability. Ran with the lights on it would flatten the battery, but with the lights off it did manage to charge. Think it had just chopped a wire on the stator.

Edit - oops, forgot about the suspension.Problem is that even with brand new bushes there was getting on for half a mm of clearance between the steel bush and the plastic bush. Fresh grease seems to make it acceptable for a few days. Only real longer term solution would be to make some slightly larger steel bushes to take up the clearance.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stinkwheel]

[whitedevil]

There are 3 things defective on all 1st gens- the flywheel, the CCT, and the transmission.
You're also limited on 16" tyres.
Unless you're good with a spanner and can get it real cheap i'd go for a 2nd gen.

[stinkwheel]

Tyres wouldn't bother me at all. They run best on BT54s and that's what you can get.

I actually found the 16" model handled better than the 17" one.

What's the problem with the transmission? I know the teeth on the selector mechanism round off after a lot of miles (mine went at about 65k) but they are easily replaced with the engine in the frame.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MikeyBrown]

[whitedevil]

1 the transmission can have a fault where the bike will pop into neutral while engine braking in second gear.


2 the stator can loose magnets causing charging issues (can substitute generation 2 engine parts to fix)


3 the original Cam Chain Tensioner that came with the version 1 bikes was prone to failure. Kawasaki redesigned this for the second generation bikes. The redesigned tensioner will fit the first generation bikes. Replacing this can help prevent the serious engine damage that would result should the original tensioner fail.

[stinkwheel]

[Kickstart]

[whitedevil]

https://www.ex-500.com/index.php?action=dlattach;topic=12936.0;attach=28069

[Kickstart]

Hi

Locked board, but the flywheels are different. Kawasaki did sell an updated flywheel for the older shape gpz500 of a similar design to the later one.

From memory the early and late GPZ500s have a different number of ignition pickups, hence the incompatibility. Early ones had 2 pickups and late ones had 1 pickup. If you use the late flywheel you will need the single pickup and the cdi unit / wiring to go with it.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stinkwheel]

[Kickstart]

Hi

Just registered to check that link.

What they are doing is chopping most of the ignition trigger off the new flywheel to use on the older bike.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[MikeyBrown]

Okay, so I've been down to view the bike and to be honest it's better than I expected

The paintwork isn't perfect but I'm aware I'm buying a 20 year old commuter as opposed to a 2 year old sportsbike. It's in an acceptable state anyway and the bike overall is good for the age+mileage. The body work is all there with no cracks around the indicators and really there is very little rust on the whole bike

I've checked the swingarm and it seems sound and it also has the Motad Nexxus full s/s exhaust so no rust to worry about there

We've decided on a price, which is £500 and they'll MOT it when I'm ready to use it on the road which I suppose is a bonus.

I'm fairly happy about it so I'm going to go and give them the dosh tomorrow (all being well) in exchange for the bike and paperwork

The only issue is that the centre stand rattles a bit but I can live with that and there is a slight cam chain tensioner rattle on tickover, but the mechanic said it's not that bad and he's 99% it's just cam chain tensioner related and on top of that my uncle says that he can sort that out if need be
____________________
Past Bikes: '97 CG125, '91 GPZ500S, '01 FZS600, '07 S/Triple, '99 ZX9R, '82 GP125, '83 GP100, '03 SV1000S, '98 ZX6R
Current Bike: '07 FZ1N
Trackdays: Darley Moor - 15/6/12, Donington - 28/8/12

[Kickstart]

Hi

Suspect there is a missing stop for the centre stand. If you are desperate the tubular rubber bungs sold as door stops will do the job.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[MikeyBrown]

[Kickstart]

Hi

Yep, something like that. Trying to remember how the stand sits on the GPZ, but on many bikes the stop is on the exhaust, so when you change the exhaust you lose the stop.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing