kz750e Resto-Mod

I'm just going to replace the one oil control ring on #3. I just bought the extra sets of rings for (hopefully) years down the road when they are no longer available.
Because I needed another head gasket, (because I removed all of the pistons to closely inspect them all.) new wrist pin clips and 4 extra sets of rings, it was more cost effective to buy a whole new piston kit and a 5th ring set than it was to buy all of it seperetly. So I will have a spare set of pistons now.

When you mentioned the heavy smoke I kinda thought you'd find a problem with the spreader. I had something similar happen on a Wiseco piston that I used in race single that I was building. The spreader seemed too long, and kept popping the scrapers out during install. Eventually I intentionally clipped a couple MM off the end, and it went in smoothly. It was a race engine, so a little smoke wouldnt be a problem. Well, it pretty much turned my engine into an oil pump, and could probably have pumped the crankcase dry in 10 minutes or so. Needless to say, I didn't make the race the following day.

Those Cruzinimage oil ring expanders don't look like the ends are designed / formed properly....it looks like the angle the two ends butt against each other is not square enough, inviting a problem with overlap.

I hope you have better fortune in putting the pistons in this time....and quite happy that the cylinder bore didn't get scored by the defective ring....

I had only one spot of trouble putting in rings before - I managed to snap a 2nd ring once on a Honda while heavy hand coaxing the cylinder into place. That also nearly emptied the sump of oil in just a few seconds - better than an oil pump would have....unfortunately it also damaged the freshly re-bored cylinder...what a waste :pinch:

So I finally have my engine back together with a new oil ring expander for #3 piston. Thankfully it runs just as it should and now with no oil smoke! So I can finally post a video of it running to show my progress.
I have been riding around the subdivision because I have no insurance and expired plates, but I snuck it out on the rural road next to my neighborhood just to see how it shifts and to check my carb jetting. It has surpassed my expectations so far. It shifts through all six gears like butter and doesn't sputter or bog at any point on acceleration. It does seem to stutter very very subtly when cruising at 70mph. But there was a 25mph wind blowing the whole day I did my road test, so it could have been that. So before I make and carb adjustments I will need to get more miles on it.



Now I have the winter to reposition my exhaust into a more aesthetic spot. As it is now, it is designed to bolt up to the pillion rear support and because I no longer have that, the megaphone points straight backwards in a odd way. Not to mention my support bracket for it is about 20" long. So I "intend" to come up with a mid-pipe to ad more upsweep to the megaphone like the vintage race bikes exhausts.

The next issue is that my Zephyr 750 carbs I got on ebay had looked to be used as a hammer at one point. I thought that the damage was limited to the cracked float bowl and caved in diaphragm lid. But after several heat cycles on the bike, I noticed that there is a long fracture in the intake side throat of the carb as well. ( I of course only noticed this just as I was finished syncing the carbs, so It means I get to do that all over again.) So I have a set of cvk32's from a zx600c on the way to replace the Zephyr ones. I tried to find a replacement carb body to replace the cracked one, but I could find every one but the one I needed.
I cannibalized my spare set of zr550 cvk30's for parts so I will end up with a complete set of 32's and 30's when I have everything sorted anyways.

The speedo is +5mph just like the one on my Zephyr. Its because the Bridgestone tires are smaller in circumference than the stock Bridgestone's of the exact same size. So when I was at 4000rpm's I should have been going 65 mph but my speedo was at a optimistic 70mph. I knew I should have bought the slightly wider and taller Battlax tire instead of the stock size. Fudge!

My kick stand is so short that it looks like the bike has fallen over. So its off to the salvage yard to find a longer replacement.

And of course paint. I simply cannot afford to have a quality job done at this point, so it looks like I am stuck with primer for the foreseeable future. Unless some one wants my basement of gpz550, zr550 and kz750 parts in exchange for a paint job?

such a killer bike!!

So, I have a quick question That's somewhat related... I have seen several videos of rebuilt engines that have a moderately high frequency sound that increases with rpm. Watching the video, it seems to be emitting from inside the engine. Is this a cam chain tensioner?

I have a kz700 and have never heard this sound. I recently switched over to a manual tensioner which quieted down engine noise by a considerable amount. While at idle and riding, I can only hear my primary drive chain, carbs (with pods, which I believe are louder than the stock box) and my exhaust. Is this an indication of something lot being adjusted correctly or parts worn out?

Again, great build! Totally inspired me to do a transmission swap this winter.

I know exactly the sound you are referring to. I would have been scared of this noise if I hadn't also heard dozens of kawasaki's make this same noise in videos. The supercharger whine on mine disappears as soon as the engine warms up.
It is not the cam chain tensioner. I am using a manual adjustment style and I am 99% confident it is adjusted correctly. (Finger snug, then back it of a 1/6th of a turn.)
I'm pretty sure it is the straight cut primary gears at the clutch hub and secondary shaft. Both my clutch and secondary shaft are from different bikes, so the straight cut gears are making noise as they "get to know each other" so to speak.
I don't believe it is the transmission as it whines in neutral and when in gear.

Also, thanks for the positive comments!

Awesome build. The engine sounds great in the video.

Straight cut gears make that characteristic whine noise. That's just how they are. KZ bikes are famous for it.

Thanks! That makes a lot of sense.

That thing just sounds amazing and I've watched the video like, 5 times... I am now convinced I will one day have a kerker exhaust. Gotta save some pennies.

I got my 1994 zx600c carbs in the mail and proceeded to make two good sets of carbs from three.
Thankfully my research was correct and the Ninja cvk32 carbs are identical in all the important ways to the zr750 cvk's.
The pressed in air jets are both exactly the same sizes.
Main Air Jet - 100
Pilot Air Jet - 150
The needle jets were also the same, but obviously the needles, main and pilot jets were all the wrong sizes but that was all replaced with the correct sizes from my Factory Pro jet kit.
The idle adjustment knob was slightly different and two of the fuel pipe extensions that split the fuel between the carbs were plastic instead of aluminum like my older carbs, but that was all easily swapped over to the proper ones.
But once I stripped them down, soda blasted, carefully removed a snapped off pilot jet, and reassembled them, I had a perfect working set of carbs with no cracks.
It was a beautiful day today, so I synced the carbs and snuck it out into the country for a 15 mile test flight. As it is, I will not make any changes to the carb settings as it seems as close to perfect as I dare to get.
In sixth gear it cruises at:
55mph @ 3500rpm
60mph @ 4000rpm
70mph @ 4500rpm
77mph @ 5000rpm
Sixth gear is really a highway gear only, as it gets down in the lower torque range at 55mph. Which is what I was kind of expecting.

Fun with carbs



iMac computer stand repurposed into a float level checking stand.



All one color of primer finally

very nice :evil:

thanks for posting,
leon

What sprockets are you using? I'm getting close to those numbers with a 530 chain conversion equivalent to going up one on the front with a 630 in 5th.