The Free Kawasaki Z650 Project

I've bought a complete head in good condition, which I'll use in place of the worn original. Thankfully, Z650 used parts are so much cheaper than those of the bigger Zeds, the head I bought being around a tenth of the price of a good Z900/1000 head. The cam chain was so loose it had worn marks in the cases where it had been flapping around. The crank, pistons and transmission were all in excellent condition, except for the 1st to 2nd shifter fork which was very worn.

Cases now welded up and machined, next task is to remove the black finish, as the engine is going to be plain alloy. Started with a test of some paint stripper, which seem to work well. So once the paint has been removed, will have the cases and the rest of the engine vapour blasted. I'm told vapour blasting is aggressive enough to remove the engine finish on its own. I'd prefer to leave it black, but a sneaky question showed my friend prefers silver alloy engines, so silver it has to be. The bike will be a surprise birthday present for his 60th in a few months time.. so have to get it done by then.



Testing the paint stripper
The next task is to remove the black finish, as the engine is going to be plain alloy. I spent hours with paint stripper and wire brushes, but wasn't happy with the results, so packed the whole lot in the car and took them to a local specialist who will case the cases a ceramic silver finish, similar to that done on my Z1000A1 engine.



Next the clutch basket showed some back lash, due to wear in the rubber bushes inside the basket. The rivets holding on its back plate were drilled out to access these bushes. A mod will be done to eliminate the back lash, by inserting 1mm thick tubes into the holes in which the bushes sit, this will lightly squeeze the bushes and so remove their loose fit.

Love the KZ650s. It looks like this one is in the right hands.

They're nice bikes, I know one with a turbo and another about to get a tuned GPz750 turbo engine. This particular bike needs to be completed asap, as its going to be a surprise birthday present to a friend... who happens to like green and whose fav bike is the Z650.

Been busy polishing the engine covers and making a start on building a new electrical system with upgraded parts, eg coils will be replaced with those from a Honda Blackbird.


The wiring on the bike was in a bit of a state, and to be fair I didn't spend a lot of time removing it, just cut it off the bike. So I knew I was going to have to start again and make my own harness. I have used the German company Moto Gadget's M unit on several bikes, but at £350 for the M-unit and £200 for their handlebar switches, I decided to look elsewhere. Ditto for Dyna coils. I found a cheaper, simpler version of the M-unit called the D box built by the German company Axel Joost, so bought one and will use it at the heart of the wiring harness.

For the coils, I was told that the coils from a Honda Blackbird were very high spec, similar to the Dyna coils, but second hand they were a tenth of the price. I bought a pair, and had to make a pair of simple brackets to mount them to the standard mounts on the frame. Only problem was that the tank wouldn't fit, so mounted them under the bracket rather than above, which shouldn't be an issue.

Had a part of the seat latch from another Zed, but not the bracket that mounts the latch to the underside of the seat, so made one from alloy plate.




Standard coils..

Blackbird coils..
…had to make a pair of simple brackets to mount them to the standard mounts on the frame. Only problem was that the tank wouldn't fit, so mounted them under the bracket rather than above, which shouldn't be an issue.

Both the ‘78 C2 and ‘79 B3 in my garage have their stock coils mounted below. The Kawi parts diagram shows the F1 coils under the brackets as well.

However, my ‘78 Kz1000A2 and my dad’s ‘73 Z1 are both on top.

Just an FYI.

Later, Doug
Yes I realised that later, but on my bike the original coils were mounted on top of the frame brackets, they fit in either position I guess.
With many changed components.. gauges, rear lamp, rectifier/regulator, switchgear and coils from a Honda Blackbird.. similar spec to Dyna coils. I had to make my own wiring harness. With the D-Box wired up, next needed to mount the new rectifier/regulator, in place of the original, which was two separate parts.

I made an alloy plate to mount the rectifier and a 10amp circuit breaker then used the one existing thread mount on the side of the battery box, along with drilling another to mount this plate. The circuit breaker is being used as a insulated distribution point to send 12v power to various components around the bike. Such as the gauges, speedo sensor and coils which are not powered directly from the D-Box.



The D-Box needs to be told a series of yes/no questions to program it. It is put into this programming mode, by turning on the ignition switch with the brake applied and the left indicator turned on. List of questions below..

However at this point I hit a problem, as when I did this, everything was dead, no power to anything. If the the bike is turned on with just the brake or left indicator turned on, all is well, but with both then nothing. Very frustrating, as I need to tell the D-box that I'm using switches not momentary contact buttons etc.

I haven't found anything online about this problem, so will have to write to the manufacturer in Germany if I cant find a solution soon.
The problem with the D-Box is solved, seems I downloaded the wrong version of the English instructions from their website, one small change is the way you go into the set up mode. I am impressed how quickly I got a response back from Axel over in Germany, excellent customer service.
The bike had to take a step back in performance, but a step forward in practicality. The rear shocks were from a ZRX1200, which at 365mm are more than 40mm longer than stock. This gave a very high seat height.. I was on tip toes, and the bike leaned over dangerously so, on its standard side stand. So, sadly the ZRX shocks had to go, to be replaced by replica shocks, The bike is being built on a tight budget, so didn't want to spend anymore on remote reservoir shocks.


Just bought this.. 1978 Z650B.. an import from the States, with a believable 12,000 miles on the clock. There is a sticker on the front forks, which says New Jersey 1980..

Got all the electrics working, but no spark yet.. got new coils and leads on the way, which should hopefully get it running. Then the restoration / mods can begin..


I only have around 8 weeks to get the red Z650B back on its wheels if I restore/mod it, so no time to waste.. day 1...

Been a busy week, while waiting for the frame to be powder coated. I painted a few small parts that I didn't take to be powder coated, including the swing arm. I didn't take the latter as it was in good condition, with little rust and perfect bearings. The bearings would have to be removed, and no doubt destroyed in the process, as if it went for powder coating, as in the oven the grease will melt and perhaps ruin the finish. Used etch primer followed by a few coats of smooth black Hammerite, which gives a hard wearing finish, similar to powder coating.

I've also cleaned up the points cover, which had some deep scratches, still got to polish the other engine covers, but at least they are in good condition. Also had the cam cover vapour blasted, which cleaned it up, but not so much that it looks new, as that would make it stand out compared to the rest of the engine.

I'm waiting for a big order from Z-Power to arrive, along with some stainless fasteners for the engine. Also found someone on Ebay who makes new side panels from ABS, which have stronger than OE mounting lugs. Was cheaper than some of the used side panels on Ebay too.

Should have the new stainless engine bolts finished by Saturday, while the rear wheel and engine spacers have been replicated in stainless.




Cam cover before


Spacers old and new
Today collected the frame from the powder coaters, and got my nuts welded.. on the end of the 10mm stainless bar which will become the new engine bolts. Next they need to be put in a lathe and the heads skimmed.




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