Time to rebuild my old GPz

[GPZ592]

So a new year is here and a (not so) young man's thoughts turn to.........................the next project !

So I dragged my old GPz 550 out of the shed determined to give it the rebuild I'd been promising to do for the last x years.

I bought my GPz550 brand new in '82 from Townsend's Motorcycles in Wallington (Surrey). It was my first sports bike and I loved it. We went through a lot together including a season of proddy racing in '85. Following a few "offs", I then re-sprayed it green and used it as my daily commute, but the years had taken their toll and the engine needing rebuilding so I took it off the road with a view to refreshing the engine and that's as far as I got.................until NOW !

On retrieving the poor old girl out of the shed, the first thing to hit me was the fact that I took it off the road in 1994 - 23 years ago ! To my eternal shame, it's been off the road more that it's been on it

Myself and a few Z owning friends are planning to go to the Coupes de moto Legande this year. down in Dijon in June. I had this idea that I'd rebuild the GPz in time for that trip. Having seen what I'm up against, I'm questioning my own sanity on that one.......................................

Anyway, to start with, here's a few photographs on what I'm looking at -

The day I bought my GPz

As pulled out of the shed

cobwebs are free !

Mark.

[ADRIAN H]

I can see you’ll be burning the midnight lamp. Good luck

[chrisNI]

Good project the small bore fours are the future - until they get priced out of reach. I imagine bits are harder to get too...

[Philippe]

Hi Mark
good luck with your project!
Give the old girl a nice face lift but remember, she's an old girl, treat her with respect!
Cheers
Philippe

[flateddie]

I had a gpz550 h1 brilliant bikes used to make my best mates 1000ST look a bit silly once the corners came into play

[Crofty]

I had a D1. Best all round bike!

[DavidZ1R]

I have a z550 a2, and I love it, just great fun to ride, some big boys struggle to get away on sharp bendy roads.

[Kwackman]

Good luck with the project.
I've bookmarked this topic as I'm interested.
I'm doing a little Z400J, so I'll happily nick any solutions to problems you work out!

[chrisw1]

Brilliant bikes .....here is mine for some some inspiration

[GPZ592]

Thanks all for the positive replies. As everyone has said - a brilliant little bike that is still "under the radar".

It won't be a rebuild to factory stock, as it's been modified in it's life already and I have a few ideas I'd like to try. I've also stashed some bits away that I've picked up from ebay & autojumbles, over the past few years in preparation for this build. Whether they all work or not remains to be seen

[GPZ592]

No time to waste, so I've dived straight in

First job was to strip the bike to a rolling chassis, so I can get it away to have the frame/forks/yokes checked for true, as unfortunately she's been down the road a few times. This also allowed me to have a better look at everything as I took it off and assess the condition of each item.

Surprisingly, for a bike that's been in a shed for 23 years, I only had 2 seized bolts

The difficult one was the rear bolt holding one of the footrest plates

But once I drilled the head off the offending item

and was then able to drill the rest of the bolt out and run a tap down the thread

Underneath there's a lot of rust, as expected, but it looks to be only surface rust thankfully and hopefully nothing too deep. I'll only know for sure once it's been blasted back to bare metal.

So the frame is now away to be checked for true, but there's still plenty more to be getting on with

[GPZ592]

FIrst thing I've started to look at is the electrics & loom. The clocks/indicators/switchgear all look as though they will clean up OK. The cases are all plastic, so no re-spraying or chroming necessary The lettering on the switchgear is faded or rubbed off in places. Luckily, you can get reproduction decals to stick on, which makes life easy.

I know the loom has a couple of repairs that will need sorting, apart from being dirty and with lots of the connectors corroded

I trapped one of the alternator wires under the sprocket cover once, which caused no end of charging problems

I also fitted a Datatool alarm, but removed in a few years later whan it failed. Unfortunately all the connectors were "scotchlok", so left patches of bare wire I had just covered up with insulating tape

[Philippe]

Hi
the electrics on an old bike can cause a lot of trouble! Clean all the contacts very good and check if they didn't get loose, you can hardly see it, just pull gently on each wire and then you'll know.
Good luck
Philippe

[GPZ592]

Thanks Phillipe.

There's a number of wires that have gone hard and a lot of the multi connectors are corroded, so the loom & electrics will need closer inspection.

I've put the electrics to one side for now, as the rolling chassis is back from Maidstone Motoliner As expected, it needed straightening with the frame, yoke and swingarm all out of line

They also found the top frame tube to be "dished" and straigthened that out too

So, I'm happy all is now as it should be and I can move on the the next phase.

As I mentioned at the start of this thread, this is not going to be a concours rebuild to factory specification. I have a few ideas on some changes I'd like to make to the bike and one of those is the running gear. I don't want to fit USD forks & huge wheels/tyres, but to try and do a few upgrades I may have done to the bike had I continued to ride it and not left it languishing in a shed !

The starting point is this beauty that i picked up off ebay some years ago (you need to look through the dirt & grime)................

I have no idea who the manufacturer is as there's no name on it. There were a number of companies around that time (Metmachex/JMC/Davida Moto) ? First one they made (550 - 1)?

It was in a job lot of GPZ 550 parts listed for the later "A" series 550, but the swingarm pivots are different between the "H" & "A" series 550, so it got no bids (apart from mine). I also scored a period Micron fork brace in the lot, so a good deal all round

Standard & aftermarket swingarm

Being a bit impatient, I took out the old swingarm and slotted in the aftermarket one, to see how it looked and if there were any potential problems and of course, there are
Firstly, I'll need to remove the centre stand as it fouls the swingarm. No big issue there, I was probably going to do away with it anyway. The bigger issue is that the swing arm is just fouling on the inside edge of the mounting plate for the front footrests.

It looks like if I grind away the inside lip of the mounting plate, then I will get enough clearance for the arm. It makes me wonder if this aftermarket arm was fabricated on a bike or just from some measurements and never trial fitted !?!

My whole thought process on this build it that whatever modifications I do to the bike, I did not want to do anything that is not reversible, so I could return it to standard parts if I wanted. So, I'm going to step away and think about it for a bit and take more measurements before taking an angle grinder to the frame...................................

[chrisw1]

I think I would use the standard swing arm ....... that one looks a bit too bulky for my eye