Hi, I’ve just bumped into this forum in my quest for information, I have a fairly tidy GPZ750 r1 twin shock. That I’ve owned for a number of years but not ridden it in the last two years. I’ve considered selling but decided to get rid of my GSXR 1000 instead and keep the GPZ but think it’s time for a bit of an update, so has anyone upgraded the suspension and I’m thinking new shocks, swinging arm and maybe wider rims and tyres, with larger discs and some better calipers. Engine wise I’m considering a wiseco big bore kit, and I’ve read about later cams from the unitrac models being the best with higher lift than the r1 , I think my engine is from one of these but cant find any way of checking my engine number to confirm this, Last on the list is a new four into one, I can’t afford a kerker but would like something like the old Harris performance systems from back in the day, so if any of you have successfully achieved anything like this I like to hear.

 

that is a beautiful Bike and actually more in the year range of what i had wanted, really love the look and the stance of that model! year, but I came across an 83 GPZ750 instead and it had mods as you have mentioned. As soon as i get it and the accompanying paperwork i can tell you more, but for sure he did the Weisco 810 Engine upgrade along with additional mods to the engine.
810cc Weisco piston kit, competition clutch discs and springs, valve job with new guides and assembled the motor with a manual chain tensioner, all that and more to the suspension etc!
I am in the process of getting all the info and will pass that on to you if interested. a small 3 ring binder is coming with it that has the list and receipts of all the mods.
Claims it runs fantastic and smooth wiht a great power range, also mentioned the cams but again I do not yet have all the info.