Kawasaki Z650 Seventies Special
- Thread starter Bevelheadmhr
- Start date
We hit another hiccup when dropping the block onto the pistons, one of the oil scraper rings caught and damaged. Its really a two an job, but due to social distancing it had to be done alone. Also when the block is rebored, it loses a slight chamfer at the base of the liners which help the rings compress as they enter the bore.
Not a big problem normally, except the rings for these pistons are no longer available... oh well, I never liked the idea of using those (slightly) used pistons anyway, so now the engine is getting a new set of forged pistons instead.
On a more positive note, I've bought a mint front end from a 2001 Yamaha R6 which a mate is breaking
.. its 43mm forks, calipers and discs will be used on the Zed, in place of the 41mm Suzuki forks I've used so far. It means a new set of billet yokes, but that's ok, my mate Jeff has a few sets of half finished billet yokes, one of which can be used for the Zed. While work has started machining the pieces to make the billet clutch cover and points cover.
Not a big problem normally, except the rings for these pistons are no longer available... oh well, I never liked the idea of using those (slightly) used pistons anyway, so now the engine is getting a new set of forged pistons instead.
On a more positive note, I've bought a mint front end from a 2001 Yamaha R6 which a mate is breaking
The billet engine covers are progressing ok, the points cover is done, while the more complex clutch cover is around 80% done.. it needs its top bevelling and drilling to take an oil level site glass, before being polished. We're making three altogether, as its not much more work than making just one.
The next problem is how to add the famous 'DOHC' into the points covers, and perhaps 'Kawasaki' into the clutch cover. I was thinking about engraving DOHC into my points cover by hand, using a Dremel, but I doubt I could replicate the 'Kawasaki' logo accurately enough to make it worth doing.
I need to find somewhere who can engrave the covers, without charging a fortune, or maybe have a badge laser cut and inset into the cover. Not sure.
The next problem is how to add the famous 'DOHC' into the points covers, and perhaps 'Kawasaki' into the clutch cover. I was thinking about engraving DOHC into my points cover by hand, using a Dremel, but I doubt I could replicate the 'Kawasaki' logo accurately enough to make it worth doing.
I need to find somewhere who can engrave the covers, without charging a fortune, or maybe have a badge laser cut and inset into the cover. Not sure.
I etch my stuff. Saline etching, with copper sulfate and salt, is super cheap, really easy and relatively low toxicity. I use vinyl as a resist most of the time.
Thanks for the ideas, I looked at a few YT vids, one shows a method that uses sat water and an electric current (supplied by a battery charger). When I have time, I may experiment with some scrap alloy plate.
Meanwhile, the clutch cover is finished, bar some cleaning up and polishing..
Meanwhile, the clutch cover is finished, bar some cleaning up and polishing..
Not much progress the last week or so, still waiting for parts, though I did collect the ZRX swingarm from the powder coaters, they did a good job as usual, finish is gloss black to match the frame, which still needs more work before it too an be powder coated.
HerrDeacon
Over 1,000 Posts
Beautiful!
I always use the same place, which specialises in bikes.. frames, engine cases, wheels etc. I once asked how they got such a good finish compared to other powder coaters... The answer was that they paid 3 times the normal cost of 'normal' powder to have the finest ground powder available. Oh and they also blank off all threads and bearing surfaces etc.. saves a huge amount of time when you get the frame back home.
Quick mock up with the rear wheel and brake.. the wheel spokes will be painted, probably black or maybe gold..
Another small piece of the jigsaw done, the billet clutch cover is polished (I hate polishing!) and ready to go on the engine .
HerrDeacon
Over 1,000 Posts
Wow 
That looks awesome.
That looks awesome.
This ship has probably sailed by now but if not then you might find this trick uselfu when installing your cylinder. I'm a one-man show and know what you mean - having an extra set of hands around for some of these jobs would really help. I attach cable ties to the outer cylinder studs, and use them to gently lower the cylinder as needed. They're strong enough to hold the cylinder in place, but moveable enough to lower it when you need to as well. I've used this technique on both a single cylinder thumper engine and a heavy old CB750 inline 4. Works a charm.
It certainly helps if you have ab extra pair of hands, and eyes when dropping the block over the pistons, sadly that wasn't possible at the time due to the lockdown. Also boring out the cylinders means they loose the slight chamfer they have at their base, which is there to help get the pistons into the cylinders. I've now decided to have the block taken out to 75mm from 73.5, as 1170 pistons kits are available, unlike the 1120 pistons I intended to use originally. Meanwhile the head has gone off to Leeds to be rebuild by the Zed head expert in the UK. Hope to have it back in two weeks, when the engine can finally go back together.
Here's the cover loosely bolted to the cases..
Here's the cover loosely bolted to the cases..
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The Z650 frame was cut in half and widened by 20mm to fit the bigger GPz1100 engine, and also allow room for a wider swingarm / wheel combo. That done, lots of parts no longer fit the now wider frame. One such part being the iconic 'duck tail'. So I reluctantly cut it in half and used an adjustable alloy flat bar to rubber mount it to the frame. The adjustment means I can alter the angle of the tail section, or fit a completely different seat unit in the future.
Then a thin steel plate was used to hold the two halves in the correct position while they were fibreglassed together. The plate was held in place temporarily with self tapping screws, which once removed, the holes were filled.
Took quite a few hours to get it done right, keeping the curved profile of the duck tail. To finish off, it was painted with
gel coat, which still needs to be smoothed down before paint. In the pic the green paint is just a guide coat to help with that..
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Then a thin steel plate was used to hold the two halves in the correct position while they were fibreglassed together. The plate was held in place temporarily with self tapping screws, which once removed, the holes were filled.
Took quite a few hours to get it done right, keeping the curved profile of the duck tail. To finish off, it was painted with
gel coat, which still needs to be smoothed down before paint. In the pic the green paint is just a guide coat to help with that..
