KZ650B/750GPz hybrid

I've had several KZ650 projects started and for one reason or another they ended as quickly as they were started. I was working on this "77B1 again and said to myself "SELF, You ARE going to finish this one and see how good they are for your self! You've been reading about them in the forums for years. It is TIME!" One day while reading Craiglist an add in M/C parts was'82 GPz 750 engine complete $150.Turns out it was a guy I had done trades with before. I had a rolling KZ440 frame and engine. he wanted, so we traded. Bolted right in. Not rubber mounted like in the '82 GPz frame . I had an 750 airbox so no problem there. It's going to take a bit of work but doable. Some months later C/L had another add in there for some later cast wheels without the rimlocks and better brakes. Hmm I have a later style rear caliper in my stash...The add had a front wheel too. In fact I had to buy all 3 wheels, 2 rears and a front. I need the 16" rear wheel for the '80 and later disc,axle and spacers for the 18" wheel I wanted to use. The rear wheel rim is a wider one than the original'77s. I did have to get aother mount and stay for the caliper to make it work. Ebay was my friend on this one.
Another time I added an on-off headlight switch when I used a Rt switch from an early XS650 houseing. 4 corner running lights by adding the 2 filliment signal lights on all corners.
Some time in the last couple months, a thought of better braked for the front might be in order. Looking at ebay (again), was a front end from an '83 GPz with axle and spacers, brake caliper with lines and triple trees. I later got the upper yoke with "clip-ons". An order to All Balls for steering bearings to mount it on the '77 frame. Ebay again for new fork seals. Recently did the rebuild for the forks and assembled them on the frame. These forks are wider and use bigger diameter tubes. The fender I used from the original forks is too narrow to use. Hmmmm opportunity to make a a fork brace from angle aluminium to use as a spacer for the fender mounting. I'm going to have to use different means to mount the headlight. A electronic or GPS speedo and electronic tach mounted on a custom mount is in the future. IKON 7610 shocks maybe someday.
I'll try to load up some pics later. I believe there are some pics in the gallery of the bike with the GPz engine installed. It's since been moved into the mancave/workshop. More later as it happens......

Seems interesting, pic greatly appreciated. :whistle:

Here's some pics as promised!

Other things I have done is to use '81 650 CSR wireing harness and fenders. Pluged the exhaust vents on the valve cover with allenhead plugs. I got the idea fron this forum. I changed the fenders because I thought they were sportier looking than the longer 'B' fenders. I found the oil cooler at a swapmeet for cheap. I'm going to have to run the oil lines either up the center to infront of the cooler or up behind the cooler come over the cooler and cross the lines so to not have tight turns on the lines to the cooler's connections.Finish mounting the top and lower mounts.

The engine I bought was stored outdoors in a dusty yard. I was worried that there was dirt in the intakes and exhausts and no amount of air blasts from a air hose would get it all out the first time the engine would be started. Along with the question of how good the valves seal and shape of the valve stem seals. So tonight I took the head off. I was impressed. Pistons are not too carboned up. No dirt in the chambers. Head gasket came off cleanly. No rust on the cylinder walls!. Walls could use a light home. I will take the valves off and clean and lap them in. Change the valve seals. I've bought a top end gasket kit and it includes valve stem seals. I will probably order a new set of rings. New carb holders too. Since the cover where the output shaft is was cracked there is probably dust in the oil. The pan will be removed and cleaned. I'm not sure if the cases will be split or not. It's not out of the question.

Check those new valve stem seals, there are some junky ones out there. The consensus around here is that Viton seals are best. This is one of the rare cases that an aftermarket seal is superior to the factory piece.
The factory seals seem pretty good, but there have been reports of cheap aftermarket seal failing in a few hundred miles.

Interesting project. I have a 78 Kz650B2. I'm planning to upgrade it with the chassis from an 82 GPz 750. This will upgrade me to dual discs in front, mags, and a disc brake on the rear. Everything seems to fit on the stock frame. To you foresee any complications to this plan?

Interesting project. I have a 78 Kz650B2. I'm planning to upgrade it with the chassis from an 82 GPz 750. This will upgrade me to dual discs in front, mags, and a disc brake on the rear. Everything seems to fit on the stock frame. To you foresee any complications to this plan?

Stosho wrote: Interesting project. I have a 78 Kz650B2. I'm planning to upgrade it with the chassis from an 82 GPz 750. This will upgrade me to dual discs in front, mags, and a disc brake on the rear. Everything seems to fit on the stock frame. To you foresee any complications to this plan?

So, you are going to take a GPz 750 and put a 650 engine in it? :blink:

No. Sorry for the not being clear. I have a Kz650. I want to upgrade it with the GPz forks, mags dual disc front brakes up front and the swingarm, mags, and disc brake in back.

Stosho wrote: No. Sorry for the not being clear. I have a Kz650. I want to upgrade it with the GPz forks, mags dual disc front brakes up front and the swingarm, mags, and disc brake in back.

Ahh, that makes more sense.

Stosho wrote: No. Sorry for the not being clear. I have a Kz650. I want to upgrade it with the GPz forks, mags dual disc front brakes up front and the swingarm, mags, and disc brake in back.

That's basically what I did..
If you use the GPz triple tree you will find it to be taller. I did the taper bearing conversion with the help of "All Balls Racing" website help and it went smoothly.