I've been taking my GPz550 for some track days, and rather than upgrade to a new bike, I'd like to spend some to upgrade what I've got a bit. At least spend a season on it. (Though I've been eyeing a Ninja 300 or SV650)
Maintenance has been all taken care of, but what next?
What suspension upgrades would you focus on? I have Racetech front springs already, and I'm looking into emulators or anti-dive block off plates. Is there a rear shock you'd recommend?
What tires are people running on our 18" wheels? Are people changing over to 17" wheels from some other bike?
Are you racing in a series? If so you need to check out what rules they have consider them in your upgrades. Corey Clough (think thats how he spells it) is a member on here and has a gpz 550 that he has raced. i would search for some of his threads.
Corry hasnt been racing his GPZ for a while ASFAIK, but he will be an endless fountain of info if you contact him.
I'll be more brief...
I raced mine for one season between other efforts, with medium level but cost effective mods, at least IMHO...
So first thing to check is your rulebook, class you can run, and in general how competitive you want to be....
mods can range from making it just track ready to full blown 680 cc kitted monster, $$$ and effort vary accordingly.
My middle of the road effort was basically:
1. Keep stock 18" rims and run Avon AM22-AM23 race rubber,
2. ZR-7 shock (cheap bolt on mod)
3. stiffer 0.9 kg/mm fork springs / blocked off antidive
4. upgrade front discs to 280mm gpz750 ones (cheap bolt on mod)
5. Brembo callipers + race pads all around (stock setup will be a serious limit / fade beyond “track cruising” level)
6. Marving 4-1 exhaust / R6 silencer (or better kerker/moriwaki
7. ZR-7 carbs
8. Stock cams degreed to 105 degs lobe centers
Regretfully, a well prepped 600 Ducati Pantah or FZ600 that are just two year older will run rings around it
Next step will be a 610 kit, megacycle cams and proper porting, but didn’t got to do it as I switched back to my CB500/4
Would these mods fit an 84-86? I’ve been looking for a bolt on front fork option or rear shock. These sound like great mods but I’m wondering if any would work for my 85 gpz550
Mine is an 84...the zr7 shock is a bolt on,
I kept the stock fork but dropped in there stiffer springs and blocked the anti dive.
Any other law I fork would be easy to install but you'll have to check ride height and trail