GPz550D1 Restomod - completed?

25 years ago a housemate passed his test and bought a GPz550D1. He promptly crashed it and decided that biking wasnt for him. It sat around for a while but when he decided to get rid of it I bought it. At the time it was running but had bent bars and some other cosmetic damage.

The bike then trailled around with me for the next 20 odd years. I checked it still ran and kept it under cover but never got round to doing anything with it. Eventually I was desperate for cash so decided to sell. Usefully, so much time had passed that it had gone from being considered a cheap hack to a valuable classic.

A friend who had just passed his test was looking for a bike so, just out of courtesy, I told him that I was selling a GPz550. I said that it really wasn't the bike for him as it was a serious project and would take a lot of effort to turn into a useful bike. However; he jumped at it and took on the project.

The engine was running (badly) but the carbs were pissing petrol, the running gear was rusted everywhich way and the electrics were fubar. We decided, rather than refurbishing 40 year old tech, to replace the running gear with something more modern and to rebuild the carbs and lash up a new loom. I did all the mechanical work: fitting a GSF600 front end, ZR550 swingarm and ZZR600 rear wheel and brake. The rear shocks were specced to give the same steering geometry as a 2006 fireblade and, handily, gave the bike a much more muscular stance. The bike was delivered as a functioning machine but needing a serious amount of tidying up. The exhaust promptly turned to lace, the can went missing somewhere, the carbs continued to be a mobile fire risk and the loom was, ah, characterful. Also the engine was leaking oil from a previously un-noticed crack in the lower case.

This is how it was returned to me at the start of lockdown, last spring. The plan was for me to make a new loom, rebuild the engine, sort out the carbs and mount a new rectangular headlight with the original fairing. Yeah, leave me alone with a bike in need of attention and stuff gets done; new horn, cleaned up and repainted oil cooler, new bars, mudguard reversed to look more period, new exhaust sourced and fitted, carbs completely stripped and refurbished, engine vapour blasted and ceramic coated. I sourced a new rectangular headlight from Hella and designed a bracket which was then laser cut and bent to mount the headlight, relays, USB charger and fairing all in the right place. Getting the fairing and the headlight to look right together, and on the bike, was a labour of love on its own.

The engine was in pieces when I got it so it was rebuilt and fitted with ZX550 cams. The carbs were completely stripped and refurbished, float heights were way off and the constant petrol dribble cured by polishing the float tangs, allowing the float valves to close properly. The sump was on and off several times as threads constantly stripped and needed helicoiling. When the bike was finally started there was a serious oil leak from the sump so, after running the bike long enough to flush oil through the engine, the exhaust came off and the sump was dropped again. This allowed me to check for debris and to refit with a new, genuine gasket. The oil leak was cured but you can imagine my reaction when the sump plug then stripped. It was carefully tapped and helicoiled in-situ taking care to catch all the swarf.

So; here she is. There is a constant list of things to do; the carbs need vacuum balanced, the oil cooler isn't quite oil tight, but she starts easily, idles smoothly and, to my eyes, looks fantastic.

Excellent job!

Wow Nice job

That's a sweet ride.

/A

Good stuff, and cool bike! Thanks for sharing.

Really nice work there mate, your mods look great.
You know you are going to have to do another one now don't you!:evil:

My second favorite GPz.
Beautiful.

Thanks all for the compliments! Much appreciated.

She's not fuelling right just now, can anyone give me some settings for pod filter/supertrapp (medium-ish restrictive) exhaust? Currently there's massively oversize jets, raised needles and air screws turned well out. Suspect it needs to be a little less extreme. 

@Mc Tavish: yes, I do have a space in the garage now so if you know of any projects lying around....

www.kzrider.com/forum/8-about-the-site/600635-signature#702657      Theres carb info here and anything else you might need for 550 info .

awesome job on the GPZ 550. Just beautiful.   My friend had one back in 1985,  we did a lot of riding and racing together,  when I had my KZ650....so many great memories of me and my buddy riding. 

Since the last post, the bike now has dynojet needles, ramair filters and revised jetting. Turns out that the cheap chinese filters were the problem. Now it's running beautifully though I'm not convinced that there's not some more to come out of it; seems to be running out of puff a bit early despite running rich on relatively small main jets (98s).

It's also got a new starter motor as a magnet broke up in the old one, and the oil cooler lines seems to be weeping. Gives with one hand, takes with the other...

With a bit more time on it I'm amazed at how well this bike handles; it's flickable and responsive but just feels nailed to the road. Honestly, it feels like it could run around lying on its side without being bothered.

It may be up for sale soon so I thought I'd give a heads-up here.

It's done! It's running well, handles beautifully, starts easily. My work here is done?

I would like to sell it but really don't know what it's worth or even where to advertise it. These bikes seem to have gone from obsolete old bangers to valuable classics in the past few years so it's difficult to know how to price it. Whatever it is I'm not expecting to get the money I've put into it back!

Any suggestions for prices, or where to advertise?

(Of course, ideally it'd go to someone on here who would appreciate it but I kinda need a vague idea of value!)