Sonic’s Workshop: 1990 Kawasaki ZX-7 Saga Part 2

Welcome back to part two of the ZX-7 story, THE TRANSMISSION THAT ATE MY WALLET. As I mentioned earlier in part one there are only two ways to go in a situation like this, new and used. I always prefer to buy new if at all possible. It usually isn’t.



I priced out the replacement parts from Kawasaki and as I expected they were out of sight. So it was off to the salvage yards to look for a well treated transmission in a wrecked sport bike. Yeah right, who am I kidding?

Well as it happens sometimes the simplest thing to find turn out to be the hardest and vise-versa. The first place I called, Ontario Cycle Salvage, told me that there was a good possibility they would have one. But I was cautioned to bring in the old set of gears to ensure the replacement ones would be an exact match. A very wise piece of advice since all tranny gears look pretty much the same until you start comparing the number of teeth, the shape of the teeth, the diameter, oiling holes, and thickness, etc. There’s nothing quite as sickening as buying what you think is right, in fact you’re damn sure you’re right, only to get home and find out you’re stupid.

Christian at OCS and I spent over thirty minutes in a cold back shed digging through box after box of used Kawasaki transmission parts. It wasn’t so bad because each transmission was complete and held together just as it came out of the bike – with thick wire ensuring nothing would be lost or out of order.

Just as we were both about to give up, we found one last transmission on a shelf above the boxes we’d just looked through. First look revealed it to be a ZX-7 transmission, but a ’91 instead of a ’90.

Back in the warmth of the store we carefully compared the two transmissions. Everything looked identical with the exception of the output shafts. The ’91 was definitely shorter than the one that came out of my bike, but only in the area that the sprocket mounts to, which was outside of the engine. The actual space occupied by the gears, shift drum and shift forks were exactly the same. I figured I would be able to exchange the worn gears on the transmission from my bike, thereby keeping the same input and output shafts, with gears from this other transmission.

Considering the price of a single new gear is about $150.00, and the fact that a salvage shop doesn’t move a whole lot of transmissions in December, I thought $200.00 for everything was pretty reasonable.

Now if you ever do a job like this, here’s two pieces of advice;

1) Don’t be in a hurry and,

2) Don’t take too long.

If you rush you’ll miss something and screw it up, while if you leave it apart too long, you’re most likely to misplace something and still screw it up. There you go, a win win situation! Of course, I ignored the second rule and left the bike for a short eleven months with pieces and parts strewn everywhere. I didn’t even drain the carburetors… Oh the shame.

So here it is, eleven months later. I lay out an old white sheet on the workbench and set about the task of swapping gears. This job looks scarier than it actually is. The key is patience and a calm work environment. It took less than an hour to swap all the gears and test fit the transmission in the engine cases. Never assume that it will be okay. It’s a big job to do this sort of thing and you don’t want to end up doing it twice because it now refuses to change from fourth to fifth. I must have manually moved those gears up and down a dozen times before I was convinced that all was as it should be.

I began to reassemble the rest of the engine replacing all the gaskets and seals in the process. No point in leaving the old stuff in if I’m already in there doing the job. It would be a bitch if I had an oil leak from a seal I could have changed but didn’t bother.

With the engine reassembled, it was time to load it back into the frame. Definitely a two person job, unless of course you want to loose some of your digits. Even with two people the job had its tense moments. Sweaty palms starting to slip, back muscles talking to you, saying things you don’t want to hear. All things considered however, it went in without incident.

Once the motor’s installed it’s not over though. All the stuff that makes it run has to be reinstalled and reconnected as well. As an added treat I had to strip and clean the carburetors that I had left full of gas and were now thoroughly gummed up! A few more hours later (and a half dozen cups of Red Rose) and it was ready to be fired up.

It’s always a bit tense … okay, it’s very tense starting an engine that’s been ripped out, gutted, and then put back. I’m always overly cautious at this point, checking oil and coolant levels more than once before I reach for the starter button.

As I depress the button, the motor cranks over and then fires up my heart always skips a bit. I figure I’ll be dead in a few more years if I keep up with this sort of thing. But all was well, the bike fired up and idled smoothly in the early morning at Sonic’s Workshop. It seems I do my best work in the wee hours.

But with the bike running, the truth still wasn’t known. Remember, it ran before, it just didn’t get all the power to the rear wheel! Now try to imagine the stress of 4 years and a stack of cash, and it all comes down to the test drive. What if I missed something? What if second and third are okay, and fourth and fifth are now a problem? All this raced through my mind as I edge it out of the driveway.

Once on the street I dropped it in gear and pulled away. First gear pulled smooth from the low to the top end and then changed easily into second. Second gear (the nonexistent on the first run) was pulling fine now, transferring the 750 cc to the rear tire without noise or slippage. Up through second and into third, same response – nothing amiss. Fourth and fifth performed the same as the rest … success! Finally, all that time and cash had paid off. I was out on a chilly afternoon in March on my ZX-7.

As usual, I could have bought a better one cheaper and been ridding four years ago. But as with all the trials I’ve had with my Virago, I feel that it only makes the relationship better. It will be the same way with the Ninja. There is a down side however. Now that I own a sport bike it’s been pointed out by more than one person I’ll have to pick up a matching jacket and helmet. Apparently it’s a fashion thing. Oh well.

Thanks for reading,


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