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Time to rebuild my old GPz

Work in Progress

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GPZ592
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Re: Time to rebuild my old GPz

#121 PostAuthor: GPZ592 » Mon Apr 24, 2023 7:36 pm

The problem with the oil cooler position and trying to modify the standard lines has rumbled on for the last few weeks with no success. I tried various local hydraulic companies but I was met with apathy and dis-interest. One well known company did say they'd have a look if I left the pipes with them so I did, but after 2 weeks of hearing nothing I returned to find they'd done nothing with them :( I had wasted too much time on this, so I ordered up a new aftermarket oil cooler/pipes/fittings, but even this was not straightforward. The sump on the GPz requires adaptors to bolt on to provide a AN/JIC -6 fitting. I'd used adaptors previously on my P&M with a GPz 750 engine with no problem at all. However, that was 10 years ago and after calling the supplier I'd used before, I found out the adaptors are now discontinued and sold their last set 3 years ago :( A frenzied search of the internet miraculously turned up a pair in Germany, which were promptly bought at great expense, but needs must :shock: I'll have to fabricate brackets for the cooler itself but at least I have a solution :)

Sump

Sump flange.jpg
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Those expensive German flange adaptors !

Flange adaptors.jpg
Flange adaptors.jpg (35.42 KiB) Viewed 36057 times


Oil cooler goodies !

Oil cooler goodies.jpg
Oil cooler goodies.jpg (91.36 KiB) Viewed 36057 times
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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GPZ592
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Re: Time to rebuild my old GPz

#122 PostAuthor: GPZ592 » Wed May 10, 2023 9:33 pm

More progress and the aftermarket oil cooler is now mounted and plumbed in . Getting the oil line to run between the no 2 & 3 header pipes and down to the sump pick up proved time consuming. The 550 is a compact engine, so not a lot of room to work and the Harris 4-1 makes it even tighter. It took quite some time offering up different angle connectors on the cooler & sump before I was happy the pipes were running right.

The first job was to install the adaptors to the sump, but I had to remove the silencer and loosen the header pipes to move them out of the way so I could get a spanner on the mounting bolts of the adaptors !

I then had to fabricate some brackets to mount the cooler and spray them black

Oil Cooler Brackets.jpg
Oil Cooler Brackets.jpg (36.79 KiB) Viewed 35999 times


And then mount the cooler to the frame

Oil Cooler mounted.jpg
Oil Cooler mounted.jpg (102.84 KiB) Viewed 35999 times


before connecting up the oil lines

Oil Pipes connected.jpg
Oil Pipes connected.jpg (124.49 KiB) Viewed 35999 times


The oil pipes look closer to the headers in the picture than they are in reality - honest :D

It was then a case of tightening up the exhaust headers before refitting the silencer and filling the engine with oil.

So now, it should be ready to fire up for the first time in over 25 years - fingers crossed :)
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#123 PostAuthor: Philippe » Thu May 11, 2023 2:44 am

Hi GPZ592

you did a great job there!
Let's hope that the engine runs smooth and everything works as it should.
You deserve that after all the good work you did.
GrtZ
Philippe
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Re: Time to rebuild my old GPz

#124 PostAuthor: GPZ592 » Thu May 11, 2023 7:03 pm

Hi GPZ592

you did a great job there!
Let's hope that the engine runs smooth and everything works as it should.
You deserve that after all the good work you did.
GrtZ
Philippe


Thanks Philippe. I'm hoping to fire it up this weekend - look out for the next update :)

Mark.
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#125 PostAuthor: GPZ592 » Mon May 15, 2023 8:16 pm

IT LIVES !

Yes, for the first time in nearly 28 years, my old GPz is a runner :D Annoyingly, one of the new oil lines I made up is weeping, so I'll need to remake that, but its not that much of a problem. However, there is something else that may warrant further investigation...............

I've run the engine up to temperature a couple of times to heat cycle the engine, so I can check the head bolts, exhaust clamps, etc. Once hot, I used a IR thermometer to check the header pipe temperatures and I found cylinders 1,2 &4 were around 200 degree C, but cylinder 3 was only 90 :shock: The carbs have been ultrasonically cleaned and reassembled with all new O rings/gaskets, etc but retain genuine jets/needles/needle valves, etc. They are all set the same for float height, slow running mixture screw setting, etc. Obviously, the engine has been totally rebuilt and all 4 cylinders give 170 PSI on a compression test. All new spark plugs & caps have also been fitted. All the plugs look the same - i.e. no 3 is not fouled up or wet ( see photo below). I did try moving the plugs around just in case I had a faulty one, but the problem persisted on no 3. I can't hear any problem in the engine note - it sounds fine to me with no misfire or hesitation.

My next steps will be to swap coils & HT leads to try and eliminate an electrical issue before looking into the carbs further. However, if anyone has any suggestions/pointers/ideas, I'd be grateful to hear them :up

Thanks.

Mark.


Spark Plugs.jpg
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#126 PostAuthor: Philippe » Tue May 16, 2023 12:34 pm

Hi Mark

congratulations with the running engine!
You'll find the reason why the N°3 cylinder is not working as it should, I'm certain about that.
If you have a spare spark plug, remove the cap from the third sparkplug, put the spare sparkplug in the cap and make sure that the sparkplug touches the engine to have a ground. When you start the engine and you have sparks on the spare plug, you know that it fires and that the problem must be found in the carbs.
Good luck!
GrtZ
Philippe
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Re: Time to rebuild my old GPz

#127 PostAuthor: GPZ592 » Wed May 17, 2023 7:43 pm

I think I've now found the cause of the issue, but still a bit of fine tuning to do :)

Anyway, I re-checked the coils & HT leads and they all tested OK and within specification. I did swap the coils over anyway, just in case ! the plug caps were new, but I did swap them over too, but the HT leads are all different lengths, so not easy to swap. I then went around and re-torqued cylinder head nuts - all fine there. Then I checked the exhaust clamp nuts and whilst the ones on cylinder 1,2 & 4 went half a turn or so, cylinder 3 went a couple of turns !

After all that, I ran the bike up to temperature, balanced the carbs again, then checked the exhaust header temperatures and now all 4 were within 15 degrees of each other :D So, it looks like a slight blow by on the exhaust gasket was the culprit.

Mark.
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#128 PostAuthor: Pizzaman » Thu May 18, 2023 5:45 am

Hi GPZ592
Just want to say what a fantastic job you have done on your GPz550!
One of my favourite bikes of the 80's
Great mods have made it so much better than new
Thoroughly enjoyed watching your rebuild, well done!
Pizzaman :roll:

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Re: Time to rebuild my old GPz

#129 PostAuthor: GPZ592 » Thu May 18, 2023 7:41 pm

Hi GPZ592
Just want to say what a fantastic job you have done on your GPz550!
One of my favourite bikes of the 80's
Great mods have made it so much better than new
Thoroughly enjoyed watching your rebuild, well done!


Thanks for the compliment - its been a labour of love and I'm nearly there ! Hopefully it won't be too long now before I take that first ride :D

Mark.
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#130 PostAuthor: GPZ592 » Mon Jun 05, 2023 8:43 pm

Well, the last few weekends have been spent running through the list of "little" jobs that I needed to finish up. You know the ones - they should only take a few minutes, but somehow they take hours !

First on the list was to remake the leaking oil cooler line, which meant draining out the oil, which in turn requires the exhaust to be removed as the Harris pipe, restricts access to the drain plug - ah, the joys of rebuilding an old bike :D I'm glad to say, that is now sorted. A myriad of other jobs followed - fitting a crankcase breather filter; fitting the fuel pipes; fitting carb filters and so on and so on..................................

Then last weekend something strange happened, I went into my garage and looked at the list of "jobs to do" on my whiteboard and there were none :shock:

Empty Whiteboard !
Whiteboard.jpg
Whiteboard.jpg (51.43 KiB) Viewed 35737 times


So now it was time to fit the bodywork back on and maybe, just maybe go for that long awaited initial run out on my old GPz - except my old GPz had a couple more challenges to throw at me :(

I started by fitting the seat cowl as I thought that would be a good place to start and it would allow me to then trial fit the seat and adjust it's mounting brackets if necessary. However, with the seat cowl fitted, the rear of the seat was sitting to high at the back and would not "latch" into the seat lock properly. After a bit of head scratching, I dug out a spare frame I have and took some measurements between the two. This showed my seat lock bracket was out of line and needed "tweaking" a bit. To save damaging the powder coat, i fabricated a bracket to bolt onto the seat lock bracket to give me some leverage to line it up. A couple of "tweaks" using a pair of mole grips on my fabricated bracket had it back in line !

Measuring the height the of seat lock bracket and fabricated plate for leverage.

seat bracket.jpg
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With that now sorted, the seat cowl went on nicely and looks the part :)

Seat Cowl.jpg
Seat Cowl.jpg (116.39 KiB) Viewed 35737 times


The tank was next, so I fitted the locking cap and the refurbished fuel level sensor and fuel tap. Before fitting on the bike, I put a little petrol into the tank on the bench, in case any of the gaskets leaked, instead the bench started to get covered in petrol from the fuel tap outlet :shock: The GPz uses the vacuum type tap that most Kawasakis of this era have fitted. Although I had rebuilt it using a new gasket kit, it obviously wasn't sealing. A strip down on the tap didn't reveal anything obvious, but I could suck air through the outlet pipe, which obviously shouldn't happen with no vacuum on the diaphragm. So I dug through my boxes of spares and found another tap. I cleaned this one up and then transferred the internals from my original tap to this one and tried the same test and got the same result ! I'm not sure exactly what to make of it, but I've ordered the genuine Kawasaki parts (instead of the "Tourmax" kit I used before) and I'll see if that makes any difference. I did also try searching for a replacement "manual" fuel tap, to do away with the vaccum type tap, but didn't find anything with the correct outlet orientation and size.

So I'm nearly there - just the fuel tap problem to sort and that's it (hopefully) !

Mark.
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#131 PostAuthor: Philippe » Tue Jun 06, 2023 3:38 am

Hi Mark

are you sure you've mounted all the parts in the correct way? Is the O-ring on the vacuum valve mounted? If that one is too small, it doesn't seal the fueltap inside. Did you mount the spring behind the valve?
You should also realise that the modern fuel is different from the old fuel. Try to put the rubber parts of the fuel tap in a jar with fuel for a few days so they can "swell", it might solve the problem.
Good luck!
GrtZ
Philippe
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Re: Time to rebuild my old GPz

#132 PostAuthor: GPZ592 » Thu Jun 08, 2023 9:30 am

Hi Philippe - yes the tap was definitely assembled correctly :smile

The new genuine parts have arrived and I'll fit those and see if it cures the problem.
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#133 PostAuthor: GPZ592 » Sun Jun 11, 2023 3:37 pm

The job for this weekend was to sort out the fuel tap leak after last weeks problems.

As I previously posted, I ordered all the genuine parts after the aftermarket kit I fitted allowed petrol to seep through when not running. Checking the OE parts against the kit, there didn't seem to be much difference, but the OE diaphragm came ready fitted to the plastic spacer, whereas the aftermarket kit only supplied the diaphragm and you have to fit it to the original spacer. Also, the "O" ring that seals against the tap body did seem to be a bit more "substantial" on the OE item, but measured up the same !

Tap ready to assemble
Fuel tap.jpg
Fuel tap.jpg (31.46 KiB) Viewed 35595 times


So the tap was cleaned (again !), the OE parts fitted and everything assembled OK until I came to tighten up the little screws that hold on the faceplate and one just turned :angry These are little M3 screws that are about 4mm long, so not much to bite into on the tap body. Looking at the holes, they're blind, but only go about halfway into the boss on the tap body. So, I drilled through the boss and tapped it out full length, which doubled the amount of thread and fitted longer screws, which then tightened down OK :D Another disaster averted !

You can see in the photo below where the screw protudes out the back of the tap body. I've ordered some shorter screws of the correct length !

Tap Installed
Tap Installed.jpg
Tap Installed.jpg (24.25 KiB) Viewed 35595 times


Then the big test - fit the tap and put fuel in the tank......................................... and no Leaks :D

I can now fit the tank onto the bike. Then it's just fitting the bodywork/seat and it's done !

Hopefully next time I post, the GPz will be complete and ready for a test run.

Mark.
"Racing is life. Anything before or after is just waiting" - Steve McQueen

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Re: Time to rebuild my old GPz

#134 PostAuthor: Z1streetfighter71 » Sun Jun 11, 2023 6:15 pm

Had one of these in black in my early 20's back in 1993 till i upgraded to the gpz750, loved that bike and cracking job on the restoration!

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Re: Time to rebuild my old GPz

#135 PostAuthor: GPZ592 » Mon Jun 12, 2023 7:10 pm

Had one of these in black in my early 20's back in 1993 till i upgraded to the gpz750, loved that bike and cracking job on the restoration!


They are great little bikes and thanks for the compliment :up
"Racing is life. Anything before or after is just waiting" - Steve McQueen


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