1982 GPz750 Phase II Making It more Unique.

Thanks for the support guys.

My right side is pretty sore but I'm doing OK. My wife wants me to stay home today but i don't think I need to.

GOOD NEWS! I just contacted Redhawk4. He lives about 40 mi away from me and he has the crankcase, crank, clutch assy, and a few other bits left over from a GPz he parted out a few years ago. So my mind is already scheming.

I was already planning on putting in a 550 6 spd gear assy. and I have the parts so that is covered. I was thinking of using a ZR7 top end so I just have to find those parts. Maybe I should go the 810 route. About the only other major component I think I would need besides what Redhawk4 has is a replacement Dyna ignition. The bodywork seemed in good shape except for the added dent to the tank as mentioned.

I'm thinking I might not have unpleasantly slammed the asphalt if I'd had a steering damper. I've been wondering for a time about getting one. Any thoughts?

That bites. I'm glad you are not seriously damaged. Based on your description, I'd say a steering damper would not have changed the outcome. Sounds like the rear tire lost traction for a second, then suddenly reconnected, pitching you and the bike to the high side.

I had a similar crash some years ago with my 750LTD. Pulling away from a stop sign, turning left. The rear tire suddenly shot hard right like I had hit ice (it was about 90 degrees and sunny). The damage in my case was not so serious, but I never figured out why it happened. The pavement was dry as a bone, the rear tire was in fine shape, and I was barely on the throttle.

It was actually a reverse low side.... if that's a thing. The rear went right I think I corrected, then it swung back left so fast and hard that it just smacked me and the bike down with a vengeance. I must have reflexively pushed off the pegs since there wasn't any injury to my legs, it would have busted my right for sure hitting that hard.

On reflection, the best explanation I can come with is that my tire must have picked up some dirt, then busted lose when I got to the far side of the intersection and hit the paint in the cross hatch marked crosswalk. I actually went down just to the right of frame in the shot of the intersection. I was trying to illustrate the amount of dirt or lack thereof that I had encountered. I didn't realize the spot I went down wasn't in frame until I got home.

It happens. I hit a light amount of blow sand getting onto the street. Rear tire started to slip out, I gave it gas and stood it up just in time. Glad you're OK.
Steve

I've gotten the little swish at the start of a turn before but this was different. I'd have to go back and look at the intersection again but I think the scenario I described was most likely.

I think I have located most of what I'll need to get her back up and running.

So far this is what I know i will be doing.

• Replace crankcase with KZ750R1 correct crankcase
• KZ550 6 speed gearset
• ZR7 oil pump
• ZR7 secondary shaft and starter clutch

I'll repair or replace everything else that's damaged with similar components.

What I'm unsure about is what to do about the top end. I messed up my head when I re-shimmed the valves the first time so I will be replacing that with a ZR7 head, which means a replacement cam cover. I think the cam profiles are similar but the compression is a little lower. This makes me unsure about what to do about the cylinders and pistons. Should I just use the cylinders and pistons I have? Use the cylinders I have but find high compression pistons? Should I use it and have it bored to 810?

Alternatively, should I get a set of ZR7 cylinders and pistons and possibly do the same mods as above?

Sorry to hear about your accident. Glad you didn't get too smashed up.

The 6 speed transmission mod has been discussed here before, I was planning to do it myself but the 750 have good tourque and a broad power band, so using a 550 close ratio box might not acheive a lot.

The later zx unitrack motor, or the bathtub cylinder head and cams would be the worth considering, particularly if you are going to 810cc from 738cc

Tyrell Corp wrote: Sorry to hear about your accident. Glad you didn't get too smashed up.

The 6 speed transmission mod has been discussed here before, I was planning to do it myself but the 750 have good tourque and a broad power band, so using a 550 close ratio box might not acheive a lot.

The later zx unitrack motor, or the bathtub cylinder head and cams would be the worth considering, particularly if you are going to 810cc from 738cc

Well duh!

I don't know why I didn't think of the early ZX750. They are pretty much the same engine. The 83 is included in the fsm and is even on the cover. I'll see if I can find something off one of those. I'm still not sure on the 810 option though.

You can blame daftrusty for the 550 gear idea. First gear is low enough that you can go up a tooth or 2 on the rear and still be plenty quick off the line, drop your cruise revs about a grand or so and really fly if you want to. The close 2-5 ratios are supposed to be great for the canyons. At least that's my take on what I've read.

Btw tyrell, do you still want that fender?

Sorry about the wreck and glad it wasn't worse.

Good luck with the rebuild, I'll be following along.

Nessism wrote: Sorry about the wreck and glad it wasn't worse.

Good luck with the rebuild, I'll be following along.

Thanks.

I'm pretty sure all the magic words I was thinking and saying while it was all going down, literally, was a significant factor in escaping more harm.

Well if you're going to redo it, might as well make it better than it was. :woohoo:
Steve