Last Updated on Tuesday, 06 September 2011 20:32 Written by Mik Tuesday, 12 August 2008 10:25

 

GPZ600R (ZX600A) Project rebuild

I originally bought a GPZ600R way back in 1986, I toured Europe a couple of times. Then due to moving from the UK to the other side of the Planet to Australia I sold my bike, When I arrived in Australia I bought a Yamaha XS400, I ended up eventually purchasing a brand new Suzuki SV650K5 (The K5 symbolises the year, i.e. 2005) You can see the bike from some of my pictures. I have done some mods to it, but anyways I digress, this sites about the GPZ600R not the Suzuki. Nothing has been more endearing to me than the original Kwaka. In February 2007 (With my wife's permission) I bought a 1985 GPZ600R from off eBay, The condition wasn't the best but it was running and sounded ok, although it was too bad to  ride it any distance. this is a list of problems found so far.

Project started January 2007.

Steering head bearings stuffed

Bearings front and rear wheels stuffed

Accelerator cables needed replacing

Fairing badly scuffed/damaged

Looks as though it has been dropped, with  damage to the usual suspects.

Front disk rotors worn out

Rear disk rotor maybe worn out

Leaky forks

No tread left on Tyres

Water leaking from the back of the motor via pipes.

I sourced most materials from off the internet through Google search, looking for wreckers around the world, and the parts that I couldn't source from Australia I got from either the UK or the USA. I found out that its cheaper and easier to buy parts from the USA Than from the UK. Parts from the UK take forever to arrive around 8 weeks, whilst parts from the USA to Australia take around 1-2 weeks. The best I had was a 4 day delivery.

First part of the project was to remove the front brake assembly along with the wheel and forks, I had to replace the seals on the front forks. The bike has 75,000k's on it. I got a set of seals from the USA and when they arrived (they just took 5 days) I stripped down the forks but couldn't get out the fork inserts without a special tool, now I could have made one up myself but being lazy I took the fork stanchion assemblies to my local bike shop and they replaced both seals for me for a cost of $100.00.

Update May 2008

Even though the seals replaced were new, I am still getting a slight leak, on one of the forks, the sliders themselves seemed to be fine, So I think that maybe the seals are not the best, they were not OEM parts. The next strip down I will order OEM Parts. I have now found that the seals are OK, The leak was coming from the connector pipes at the top of the forks and running down to the seals.

Whilst I am waiting for my disks to arrive I have proceeded to do the following, I stripped down the top of the engine just basically to adjust cams and have a look at the basic condition of the engine, the engine looked pretty decent with no obvious signs of wear and plenty of oil around.

When I emptied The coolant from the engine it was all rusty, pretty bad, I figured that this was due to the fact the bike had been sitting around for quite a time.(5 years to be precise) I replaced all the water pipes just by purchasing the rubber piping at Autobahn, I took my old stuff along so we could get a close match.

After starting the bike I did have problems with it when it got quite warm, it wouldn't start again, I purchased some Accel coils from the USA at a cost of around $180USD for the pair, wreckers coils were going for around $60.00 each coils set and new Kawasaki ones $170.00 each. The spark on the coils looked pretty weak so I figured (Like you do) That replacing the coils would fix the problem, well it helped but didn't cure the problem, I replaced the spark plugs with the new platinum plugs as these don't need changing often, when changing the plugs you also have to remove the water pipe that sits on top of them,  probably know some bright spark (no pun intended) may have figured a way of removing them without this procedure.

I stripped the ADVS System that it sitting at the bottom of the front forks, one of the adjusters at the bottom of the ADVS was broken so I sourced a whole spare unit from here in Australia. worked like a charm. These have been rebuilt with all new rubber grommets/washer.

All of my bearing needs were sourced from Pyramid Parts and a very reasonable price and delivery was quick cant recall if this mob were in the UK or USA.



Back to my engine problems I did a search on Kawasaki.org and found other people had the same problem. I replaced air filter and I poured about 3 small bottles of Carby/Injector cleaner into  the petrol and ran it through the engine (it was knocking so bad) but only for a short while, enough just so that I knew the carbs where full. I then let the cleaner stand for 3 days, then I replaced the mixture in the tank with nice clean petrol. and ran the engine again this time it was a lot better but I still had problems and wasn't confident that I could go out park the bike for a few minutes and restart it, I would start ok stone cold. whilst I was sat around the bike contemplating life and just messing I noticed a loud ticking noise Ship I thought the tappets that I adjusted  must have come loose, I wasn't looking forward to stripping down the top end again, so I got my trusty screwdriver shoved it at my ear and tried to get an idea to where the noise was coming from (My wife came in a laughed when she seen a screwdriver sticking out from my ear and attached to the bike engine.) when looking around I looked up and seen a bright spark arching from my super duper coils to the frame and it was this that was making the ticking noise, phew one relieved person.

When I was running the engine I noticed from the exhausts that one side was running a lot colder than the other side so I figured out that the carbies are out of balance, So I purchased a carb balancing kit for around $140.00 delivered from the UK (It was going o cost around $100.00 to have a mechanic do this for me.) these were called Carbtune Pro, they had 4 pipes one for each carburettor  and has steel rods (Not Mercury) in them. I followed the manufactures instructions in assembling them and after around an hour or so I managed to balance them quite well, it wasn't hard it was just fiddly. What I did find is the side that the exhausts was cold on was the side of which the carbies were totally out of sync. I now have a motor that starts well hot or cold.

I stripped down all my fairing panels and have sent them off to be re sprayed, I was asked if I wanted them just tidying up or like new, I opted for like new the cost for the following items will come in at around $1500.00 for the petrol tank,  fairing, bottom belly pan, the side panels, the seat wrap around and the front mudguard. I asked to keep the original colours. I sent them to a company in Spotswood, Melbourne, Victoria.. They should be ready around second week in July, I will post pics when I get them back on the bike.

Biggest annoyance, screws made from cheese. I have tried to replace all there where possible with stainless steel allen bolts..

I have the following to do before I get the bike back on the road.

Fit front disks and pads ordered....Done Aug 2007

fit rear Tyre and disk and pads ordered....Done July 2007

refit fairing painting in progress....Done July 2007

bleed front brake system...Done July 2007

bleed rear brake system....Done July 2007, still soft though.

New Fairing Screen...Done April 2008.

Long Term projects.

Either new original exhausts or re skin old exhaust system. I have now opted to buy a new OEM set cost around $2200.00

strip bike down and re-powder coat all framing work.

re-upholster existing seating. Done Oct 2007

Replace RHS handle bar, found it was broken from a fall in the past. I have not replaced this as yet just tightened up the fittings.

Basic Trouble Shooting

Is your bike too  Lean or Rich?

To check if the bike is lean (to little fuel for the amount of air reaching the engine through the carburettor) at any given throttle opening, partially cover the air-filter intake with a piece of duct tape; if the carburettor improves, it's running lean. If you suspect the bike is running rich (too much fuel in the air-fuel mixture)), remove the air box top or the air cleaner element; if the changes are for the better, the bike was running too rich.

Troubleshooting

A lean condition is the end result of too little fuel and too much air. Slightly lean conditions create ride problems. Worst-case scenario: Lean conditions can and do destroy engines. Holes in the pistons, burnt valves and trashed main bearings are the direct result of lean mixtures.

Rich mixtures are the end result of too much fuel and too little air. Rich mixtures waste fuel, contribute to carbon build up and pollute the air.

Usual Lean Conditions:

Poor acceleration; the engine feels flat.

The engine won't respond when the throttle is revved open, and it picks up speed as the throttle is closed again. (A too-large main jet also copies  this symptom.)

The engine runs hot, knocks, pings and overheats.

The engine surges or hunts when cruising at part-throttle.

Popping or spitting through the carb occurs when the throttle is opened. Or popping and spitting occurs through the pipe on deceleration with a closed throttle.

The engine runs better in warm weather, worse in cool.

Performance gets worse when the air filter is removed.

Usual Rich Conditions

Engine acceleration is flat and uneven and loses that "snappy" feel.

The engine's idle is rough, uneven or lumpy, and the engine won't return to idle without "blipping" the throttle.

The throttle needs to be open continuously to maintain acceleration.

Black, sooty plugs, a sooty exhaust pipe and black smoke from the tailpipe that stinks of unburned fuel.

Poor fuel economy.

The engine works better when cold. Performance falls off as it warms up or the ambient temperature rises.

Engine performance improves when the air cleaner is removed



The common solution to get the bikes to idle is to adjust the idle screw, while this given an immediate goal it doesn't correct the problem and you end up with the symptoms described. Kehin carbs are more difficult to tune than a Mikuni, but once done an adjustment of the air screw will take care of most conditions.

BUT....on most bikes, there is a screw independent of the carbs. It's usually close to the throttle cable and in most cases is a thumbscrew that can be turned by hand. What this thumbscrew does is limit physically how far the throttle plates close. Regardless of the carb setup, if the throttle plates close too much, the bike will stall, and if they are open too much, the bike will rev.

If you have a multi carb setup, if they are not balanced the idle is going to be erratic regardless, On my Gpz600R I bought a Carbtune Pro from around $140.00, It took me approx an hour to do, but afterwards the bike starts and runs a lot lot better. one way to tell if your carbs are UN-Balanced is to warm up the engine and place a hand at the back of the exhaust outlet (not touching the pipe) and if one side feels  colder (or takes longer to warm up) than the other exhaust you can be sure you need to balance your carbs. It is not a hard job to do. Out of a 10 I would rate it at around 3-4 in difficulty.

The Kwaka had a hot start problem, it would stat fine when cold, but I couldn't start it after the motor was armed up to temperature. I balanced the carbs then the starting procedure I use is as follows.

Turn petrol tap over to prime until you can smell petrol, open the choke to approx half way, then hit the starter button slightly longer than usual, now works every time for me. but bikes being different you may have to work out your own starting procedure. It may be you don't use the choke at all, or you use full choke. I did this at home so I wouldn't worry from being stranded.

 

 

Bottom end rumbling.

One common problem that seems to be an inherent feature of GPZ600R'S is a bottom end rumble, rattle, or knocking noise, even my bike has this and the consensus seems to be that so long as the noise disappears when the bike is revved above 2000rpm that this shouldn't be cause for concern, and again one of the main things to do to reduce this rumbling sound is to make sure your Carbs are balanced and make sure that your valve clearances are correct you can check the setting here..

 

 

NEW FAIRING (update July 2007)

It finally arrived, couldn't wait to fit it, any ways managed to get everything back on without any real dramas and I also bought new Yamaha Fairing screws as Kawasaki didn't have any. After I fitted the parts I took the bike for a quick ride up the road and on the way back into the driveway The front forks clunked out, uhho I thought this is not good. got the bike back into the garage and pulled off the tops of the handle bars to expose the screw cap on top of the fork stations, took them off and out came the spring. I measured up and the height was only 120mm, I could have sworn I had put in the correct ml of fork oil. It turns out that I did, but after reading around the internet and service book it also says that fork oil level should be 335+-2mm, Stupid me though I first measure with a wood dowel forgetting the displacement theory. So anyway got a coat hanger, stripped it and re measured I was well low, so I topped it up to 340mm height and hopefully everything is now ok. I used 15 weight fork oil. with the slight extra height and weight I don't think I will bother putting any air in the front, but will decide when I have been on a longer, much longer ride. I have fitted new sintered pads, but I originally wanted std pads for the rear brakes, but ended up getting the sintered for the same price, mainly because the shop didn't have any of the other pads in stock. After I fitted the rear pads and re fitted the complete rear wheel then after tightening the rear nut the whole of the rear wheel locked up, just wouldn't turn. So I checked and re checked the chain, it seemed ok, I thought maybe I put some of the parts back together wrong. but before I decided to remove the whole of the back wheel, I decided to loosen the brake calliper and pull it off the bike, after doing this it looked ok, so I refitted thinking that the wheel will be next to come off but it turned out after the calliper refit everything went rotated smoothly again, must have been a brake pad/calliper problem but I don't know what exactly.

 

Next Project

I am nearly up to the stage where I can get the bike registered/roadworthy, I still have a couple of projects to do such as the disk rotors and the seats to be re upholstered. and of course the exhausts.

Problems found after first test run.

I had accidentally hooked up the inlet and outlet tubes that go from the radiator to the small bottle in the lower fairing and it was leaking after stopping the engine when it had been running for a while.

I had to re bleed my front and rear brake callipers as I felt they they were not hard enough, although it could be the old brake lines that need replacing.

I also had to recheck the oil in the front forks as they was a loud clunk when going down the curb, I measured and found that there was only 120mm and they should have been 340mm +/- 2mm, I placed the correct amount in the forks and the suspension is now a lot  lot better. the fork oil I used was a 15 weight. I am not planning to put any air in them due to the heavier weight oil.

One thing I did find is that compared to the SV650, The GPZ600R needs a bigger fist full of revs to get it to go at any speed, So I suppose I will just have to compensate my riding style when switching between the 3 bikes.

 

I have managed to get the bike from out of my garage and go for a ride, I still don't think my front forks are set up correctly, they are ok when riding normally on normal roads, its just that going down a curb that is still "clunks" Maybe I still have to play around with oil levels etc, Tip if you know anyone with a car you may be able to borrow and use a dipstick to check your fork oil levels if you have one long enough. maybe the oil I put in was too stiff for the bike. The bike runs absolutely true when you take your hands off the handlebars although I don't recommend you do this at any speed and certainly not when there is other cars/traffic around. I had to re bleed the rear brake calliper, it took a lot of foot pressure for the brake to react, I think I also have to re bleed the right hand front fork calliper and when I pulled up I had a feel of the disks and the right hand side was noticeably cooler than the left hand side disk rotor.

I have a permit from our local roads authority so early next week (Beginning of August) I will be putting the bike in for its roadworthy, I don't think I will have any problems, if there is It may be because the indicators flash too quickly.



AUGUST 2007

Mid August and my front disk rotors finally arrived courtesy of my local bike shop. I will now have to take off the front wheel/mudguard and change them, while I am at it I will also replace the existing rotor bolts with new bolts and use some loctite to finish off the job, a screen has been ordered in smoke colour, not the original as that was a clear screen. I would say that within the next 6 months the bike will be as new.

I found out when registering the bike for the road, that it was over 5 years ago that it was last used on the roads so all that time it has just been sitting somewhere gathering rust and dust. The bike passed its roadworthy with flying colours and the tester was very surprised when he rode it and told me "it felt like riding a new bike" He did pick up on a loose handle bar, at sometime this had obviously been dropped and broken as when I pulled the accelerator bar apart  to have a look the handlebar was being held by a grub screw, the original was just a tight push fit. the screw itself cant come out as the braked master cylinder backs onto it. This will be just another thing I need to add to my TODO list. you can check out the pictures of the new rotors on my pictures page.

 

SEPTEMBER 2007

I have had the seats recovered, which was done for only $110.00 although not too happy with the finish but they will be ok for the time being.



I also installed a new fairing screen which I am very happy with, BUT being the lazy bugger I am, when I attached the old screen I only done up half of the screws, and had it our for one or two rides, when I came to putting on the new screen a section at the top of the fairing was broken, you cannot just glue these on they have to be welded, well I did this but didn't do a good job, will have to put it on my to do list for next winter

 

October 2007

I have just fitted a Xenon high brightness front light globe (Bulb) The high beam works by magnetics raising and lowering of the bulb itself. Gives off a far brighter light than the old OEM. The kit came with a ballast, and a control box. Had to get additional info with regards to the wiring but once received the missing diagram It fitted like a treat. the light now glows brilliant blue.  



The GPZ is not running the best of the last week or so, being a little un reliable with starting. I have re balanced the carbs but it hasn't made much difference so now I am back to riding the SV.  I have bought a 4 pack carb kit from the US and when I receive them I will pull off the Carbs completely and give them a good cleaning and refurbishment. I just have to remember to take lots of pics when pulling them apart.



Nov 2007

The GPZ is giving me problems by not being able to start from Cold, I thought I had solved this problem, anyways after pulling the tops from off the carbs I have found that one of the rubber diaphragms has a rip on the edge of it, which is what I think may be the problem. I have bought another set of Carbs and I either plan to fit them if they look good enough or I will cannibalise them to use as parts for my original set. I also bought a 4 set kit from off eBay to re condition the carbs but it turned out that it was the wrong kit for my bike even though the advert stated my year and model.

 

Picture taken 11th may 2008.

also over this same weekend, I dropped the forks down from the triples as to improve handling.

 

Latest update May 2008

I accidentally broke the fairing screen, I think I must have fitted the screws too tight when originally fitting the new screen. The lug (ear) on the fairing also snapped off. I have has the fairing repaired and a new screen is now fitted. The new screen was around $100.00 less then the Eramax. The Eramax screen seems to be made of thinner Perspex than the new screen. I fitted another set of carbs due to performance and starting problems, a set that only had around 20,000ks on them. after fitting I still had some problems starting in certain conditions so I went back and reset all the valves (I thought that this was contributing to the starting problems but just didn't want to do it. Anyways I bit the bullet and now the bike runs like a dream, well almost its now running rich so I have going to have to do some fiddling with the replacement carbs set up.

 

 

April 2010

I have ordered another front tyre, the last tyre I got took 12 weeks to arrive due to the fact that the rims are only 16inch. take this into account when doing your project. I ordered and fit some Front brake lines last week in the transparent red from HEL. Renewed the brake oil and bled them.

I have ordered parts (New Old Stock) from the US which will replace existing parts including foot pegs, RHS Exhaust (still looking for the LHS) LHS hand grip, key ignition and handle bar electrics.

I bought a product called "wow black" which news any plastic (mainly black) on your machine and brings them up new looking. but I am a little upset as the RHS of my fairing has a craze of cracking starting to go through it, so will be looking at that item before too long.

I have an old GPX in my back garden that I am stripping down and the plan is to use parts that can be sand blasted and re powder coated, then fit them to my bike. I will take of the parts identify the parts numbers and make sure that they match up with the GPZ parts numbers.

Just bought a replacement battery as its been 3 years now and the old girl getting a little harder to start these days (Bit like the missus really)

I wanted to replace the ignition switch nut of course its still original and was held into position by pins and a special rivet washer, I never really tried to remove it as the other bike has a black yoke cover with the screws holding the ignition switch in place, I removed this and found it was the same part number and hence this is one of the parts being blasted and powder coated.

I have taken a heap of parts to the Powder Coaters and having them sand blasted and powder coated pearlite silver and gloss black.

I found that one of the fairing inner cowl screw holders has dropped off, so now I have to see how I am going to fix that up. I am also going to be taking my new old stock petrol tank to the powder coaters and have him respray it.

 

I am soon going to re set the tappets and will take a lot of pics and post them in a section here. I will also be balancing the carbies.

 

June 2010

I have a spare bike, i am now stripping this bike down and sending parts out to be re powder coated.

I have sent off the following, wheel, swing arm and parts, fairing holder, radiator fan holder, tank stop, centre stand, seat connectors and other smaller parts.

The centre stand was a pig to take off.

I have also purchased all materials to do my own chroming and plan to chrome various nuts/bolts and other bits. have a look at "Chrome your nuts" through the menu on the right hand side of this page.

 

Here are pictures of before and after powder coating my Wheels.

Wheels removed in original condition.

 

 

Wheels after powder coating.

I am very happy with the final result.

As a matter of course, I changed the bearings, The other bearing where only 2 years old and had not done many miles, but as I had to remove the bearings in the first place and a new set of 4 only cost me $20.00 then it was worth replacing the old ones with new ones. I replaced both the front a rear bearings.

 

 

In July I am sending my new petrol tank out to be resprayed as well as having some repairs to my fairing, the fairing has started to develop some cracking and I need to get this repaired I have also lost a lug from the RHS that holds the black fairing shroud.

 

October 2010

Well after my trip around Europe finally got home and my Fairing has been painted along with my new petrol tank so I fitted these and had a problem of seals drying out whilst my bike had been sat there for 3 months without petrol running through them. I had leaks coming from my pet cock and from the carbies, I changed the seal on the pet cock and let my carbies stand with petrol in them and also gave the carbies a couple of hard taps witht he end of a screwdriver. After a couple of days I was able to ride my bike without any more leaks.

I have a couple of more projects I want to get done and these are take off the swingarm and have this re powder coated along with new bearings being fitted, I dont have the tools to drift out the bearing so I am having that part done for me. Then I will concentrate in getting some new exhausts custom made as my exploration looking for a new set around the world has so far failed.

 

January 2011

I had new exhausts custom made and tried to keep them looking close to the original as possible.

 

March 2011

Removed swing arm and had it along with a few other parts powder coated, refurbished the rear brake caliper and fitted new chain/cogs

 

September 2011

Reset tappets, done a service and had the rocker cover polished up.I also replaced the platinum spark plugs with new platinum plugs, well worth the expense.

replacing new petcock. (nos)

I am thinking of putting it onto a dyno to check the power output and to see if its running lean/rich

 

 

I might later break this page up into individual years.