Gpz500 maintenance help

[pompousporcup...]

Hi all,

Had the bike a week now and have noticed some issues that need sorting. I expected it and tbf i like to tinker with things so am quite happy to sort them myself.

I have a few questions for y'all about what to do. I started by getting panels and some bits off to clean. Had a good go at cleaning and re-oiling this chain too which was farking messy! Anyway.

Firstly, fairing bolts.. the little allen key ones that hold the side panels on. Are they a specific thread pitch? I couldnt find replacement ones online but can get a couple off ebay fairly cheaply. Anybody know the size and thread pitch?
The rhs side panel bolt is farked so i cant actually get it off and don't want to forcefully remove the bolt if i can't get the correct one straight back on

Chain - needs replacing -_- will get round to it at the end of the month.

Secondly, there's an oil leak i cleaned the sump up a bit and got the majority of the gunk off the front/engine and this morning i noticed it appears to be coming out of the sump gasket, running towards the front and running down the shifter part too - hope that makes sense. Its not a lot but enough for me to notice if i leave it parked for a little while.

Is it simply a case of draining the oil and replacing the sump gasket are there other gaskets/rings that need to be done at the same time? Anything i should whilst i'm there?

Considered fitting a larger rear sprocket for a bit of added acceleration..i think stock is 42 teeth rear. Has anybody done this to theirs and if so what size did you go for? Any noticeable benefit to acceleration? Not too fussed about top speed on this bike.

To prove it happened
https://i176.photobucket.com/albums/w188/Sharpe2002/IMAG2058_zpsjgb8tmf3.jpg

Thanks
Dan

[DrSnoosnoo]

I have the ZZR which is pretty much the model on from the GPZ.

I'd have thought my experiences would be similar.

Fairing bolts, I just bought a bag of A2 M5 and M6 socket head bolts and they've fitted fine wherever I've needed them. (So standard pitch of the relevant bolt size)

Replacing the sump on mine was easy but very time consuming, as I had to remove my downpipes. I'd have thunk your downpipes would come to a collector just behind your sump, I may be wrong though. Check this out as I would suggest spraying penetrating jizz onto those header bolts for a good few days and nights before you plan on taking them off!
____________________
I'm Sam; Northern, Ginger, Lover
Did have: '95 ZZR600 '83 CG125 '97 ZZR1100 '15 Hypermotard 821 SP Do Have: '10 ZX10R

[pompousporcup...]

m5 and m6 you say. Will get a select in the right lengths and see. IF its standard pitch then all is well

I looked at the zzr6. If i hadn't won this one i'd probably have one too This gpz is so light and confidence inspiring (read forgiving )

Mine has an aftermarket SS 2 into 1 manifold on it, not sure what brand but looks pretty new (no pitting or anything..yet. Cleanest thing on the bike) Sounds great too..Shouldn't cause too much of an issue getting them off - come to think of it, it goes down the side of the sump so may be blocking access to one of the bolts.

[Dalemac]

Buy a thread pitch gauge. For £10 you will put it to good use over the years.

Oil leak, if its due an oil change then just change the oil and be sure to replace the seal.

TBH i always service bike when i buy it, regardless of whatever the previous owner says has been done. That way you know everything is OK.

A few other notes on the gpz engines:

They have a manual cam chain adjuster so be sure to check and reset this - is as simple as removing the tensioner, resetting and putting it back into the engine.

Also, valves are so easy to do it's no bother to check them at every service. Simply remove the rocker cover, measure accordingly and adjust. Tap and bucket so this is as simply as loosing, adjusting then re tightening. Make sure the engine is stone cold first.

They are inherently noisy engines so if the above has been done and it is still noisy then don't panic too much.

There is a Haynes manual for the GPZ500, buy that too.
____________________
YBR125 -> GPZ500S -> SL1000

[DrSnoosnoo]

If you can work it around not having to take the exhaust off it'll make your task easier.

I have 90% M5 but then a few are M6, I bought 100 of each at 20mm length (screwfix are quite cheap for them, cheaper than sellers on eBay). Some are too long and could do with being shorter but it hasn't bothered me for keeping plastics on.

I would have thought your bolts would be the same size as M4 are getting very small!

Here's some links for example:
M5 socket button
https://www.screwfix.com/p/socket-button-screws-a2-stainless-steel-m5-x-16mm-pack-of-50/62787

Then I also have M6 socket caps
https://www.screwfix.com/p/socket-cap-screws-a2-stainless-steel-m6-x-20mm-pack-of-50/19472
____________________
I'm Sam; Northern, Ginger, Lover
Did have: '95 ZZR600 '83 CG125 '97 ZZR1100 '15 Hypermotard 821 SP Do Have: '10 ZX10R

[pompousporcup...]

thanks guys Haynes manual just had for a fiver from halfords. WIN! Will have a read through that.

Had a ride around during lunch at work and cannot seem to see where the oil is coming from. Its either part of the sump gasket on shifter side OR where the shifter mounts to the block which then runs down the sump. Gonna brush everything and wipe it down duper super clean so i can try see where it starts.. there may be two leaks knowing my luck

Just ordered an oil filter, sump plug as thats had it from the look of it, couple of spark plugs, gear change gasket, sump gasket and gear select oil seal..Its got to be either of those 3 right

Does the gpz have a fuel filter at all? Anything else i may be overlooking? (I have 10/40 motor oil in the garage already.)

[Dalemac]

An air filter if it's due.

There is no inline fuel filter but there might be one in the tank. I never looked to be honest.

Does it run OK? If the bike has been sat for a while the petrol in the carbs will emulsify and cause the floats to stick, can cause all kinds of weird fuelling issues and even cause it to run on 1 cylinder. But if it runs fine then i'd not bother touching the carbs.
____________________
YBR125 -> GPZ500S -> SL1000

[pompousporcup...]

did actually get an aftermarket air filter too dont want to run stacks or anything yet. its a daily where fuel economy is king. I run stacks without a filter on my dual carb crx and it made it more thirsty..did sound nicer though.

Trying to get this thing "stock" and just get it running a bit better.

I couldn't see an inline filter when i picked the tank up off the frame but thought i'd ask in case it was hidden somewhere. - on that note, if i remove the tank, can i just keep it upside down so it doesnt piss fuel everywhere? or is it best to crimp the pipe and remove it off the carb side?

Previous owner said it was sat over winter without a start so no doubt there is a bit of muck in the carbs. It starts, idles around 1.5k and seems to pull really well above 4k onwards so for now it seems okay.. It is certainly a bit lumpy when cold so could be down to the carbs being dirty or not balanced properly - i plan to get that done by a bloke at the end of the month when i get a new chain.

[pompousporcup...]

One thing i did notice is the choke is pretty sticky..not sure if its the cable or the butterly yet as i havent got that far.. needed to get the tank off but was apprehensive about fuel pissing out everywhere so wondering on the best action to prevent that

Thought i'd broken something yesterday when it failed to start after putting the tank back on... fuel in the bowl ran out and it died.. almost killed the starter before i realise the stopcock was "off" - idiot

[stinkwheel]

You need a long, thin wall tube spanner (or the one from the tool kit) to get the plugs out. A socket wont fit. There is also a lot of grit and much which gets in the plug recesses that is tricky to get out. You don't want it inside your engine. Best way is to soak in WD40 for a couple of days then blast it out with an airline before you try removing the plugs. Other way is to get some blu-tak on a bit of dowel and a decent light to extract any grit manually.

External gearshift mechanism is under a seperate cover on those engines so an oil leak around the gearshift area could be easier to fix than it initially appears. Not necessarily from the sump, the external selector mechanism is under a cover with a paper gasket on behind the fromt sprocket. This doesn't become apparent until you remove the sprocket cover, sprocket and the deflector plate from in front of the sprocket then clean all the crud off.

That said, my vote is for it being oil flung up from the chain or running back from a leaky oil filter so be sure to include the area under the front sprocket cover in your clean-up. Remember oil can track backwards a long way along an engine. .
____________________
“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.

[pompousporcup...]

little update:

Filter is clean..well, there is a load of crap around it but no actual oil dripping.. Unfortunately cleaning off the sump/block has showed just how bad it was. I think the oil was being soaked up by a lot of the shit stuck to the sump but now that its clean it looks like its come out faster.

Appears to be coming out of the shifter fork O seal, running down the housing, along the side of the sump and collecting at the front (on center stand, so engine is angle slightly forward with back wheel of the ground)

It travels a fair distance before it actually drips to the ground

Is that fork difficult to remove? I can get to the two (iirc) bolts but the lower frame looks to be in the way for removing it

[stinkwheel]

Difficult to remove? Yes and no.

Compared to most bikes it's a thing of beauty and a joy forever.

It does however take a degree of wiggling and swearing and you need to take quite a few bits off first but it is removable, it is removable with the engine in the frame and it can be done without dropping the oil if you lean the bike against a wall so it's tipped over to the right (this also makes it easier to see).

You need to use the correct paper gasket when replacing the cover as the gasket paper shims out the mechanism. Too thick and you'll get play, too thin and it'll be stiff so either buy a proper one or cut one outt from 1/64" (0.4mm) gasket paper.

Once the cover is off, the mechanical seal should just pop out. Every chance you'll be able to source a new one from a bearing factors for pennies if kawasaki ones prove expensive. Make sure you clean and polish the shaft before re-installing and protect the seal from the splines by wrapping them in PVC tape.

Worth checking the hooks of the selector pawl aren't rounding off and lightly filing them back to a square edge if they are.
____________________
“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.

[pompousporcup...]

oo that looks a bit fiddly. Will probably make more sense once i have it all in pieces.. probably

Got a new chain and sprocket kit on the way now anyway so will see as i may as well do it as one job if its going that far

Thanks for the help guys.

[pompousporcup...]

1 more thing

I'm going to pull the carbs off and see what kind of gunk is in there. Is there good place to get replacement carb bits specifically for the gpz?? Rubbers/diaphrams/needles etc etc?

[stinkwheel]

Remember, you probably just need to take the cover off, not remove/dismantle the selector forks too.

I would leave the top-end of the carbs alone unless you have any reason to suspect there is a problem. A torn diuaphragm would be apparent without taking the lids off.

As a matter of fact, if there are no running issues, it idles well and pulls cleanly through the rev range with a kick up the arse at 8k prm, leave the carbs alone, you are more likely to cause problems than solve them. Or to paraphrase "If it aint broke, don't fix it.". If it's rattly at idle, balance them.

On a 1st gen GPZ, the one bit of major preventative maintainance I'd consider doing is binning the original alternator rotor and replacing it with an electrex one before the magenets fly off, trash the alternator and pickup coil electrics and dump a load of magnetic swarf in your oil. (poor quality glue was used to hold them on, fixed for the 2ng gen engines). So if you're determined to spend money and pull your bike to bits, that is a known issue with your model.

Down to if it's worth spending £150 on such an old bike. May even have already been done?

Your unitrack bushes will almost certainly need changing.
____________________
“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.

[Dalemac]

As per my previous post and Stinkwheel's post, don't touch the carbs unless there is actually a problem!
____________________
YBR125 -> GPZ500S -> SL1000

[pompousporcup...]

No stranger to carbs, although no expert either, but im not talking about changing jets or needles or anything like that. Just a check and clean up to try get it running a bit smoother as its lumpy down low and i feel like its holding back, even above 6/7k rpm.

Not intent on spending too much money either as it was meant to be cheap commuting but there are a few things that i feel HAVE to be done. The oil leak and overstretched chain/warn spockets fit into that catagory.

Found a 2 part rad flush pack in the back of the garage which i'l use this weekend as it has an erratic cooling problem. When riding, it never really gets above the second line (there is dead cold and then about half cm above there is the second line, big gap for what i assume would be normal operating temp and then "the red") When stopped in traffic the temp goes up and up and up above the half way point. I havent let it get above 3/4 either to see whether the fan will kick in. Could be the 'stat not working correctly. IF a flush doesn't solve it il look further into it.

[stinkwheel]

[pompousporcup...]

That is good to know, thanks thought it might be a bit odd as the idle revs move up to around 1900 or so after a 20 minute ride. Assume the engine is properly up to temp by then so need to see to that.

Are those gauze filters accessible?

She's is an old girl now. Getting on a bit but I love it. Getting my licence is the best thing I've done in a very long time.

[pompousporcup...]

The fun continues

On the ride in this morning just minding my own business when suddenly! a wild pot hole appears

Ground was wet and shiney. No point swerving, just along for the ride. Now my speedo doesn't work -_-

How robust is the speedo 'box? trying to sus out whether its likely to be the cable or the speedo gearbox thingamajig at the front

[wr6133]

[pompousporcup...]

[pompousporcup...]

[stinkwheel]

[pompousporcup...]

WOW waayy off tbf i'm posting during waiting times at work so must have skim read that and not checked what id written thanks for confirming

isnt that the lhs?