Where have all the second gears gone?

Lost second gear in my 78 1000, so i decided i would swap in a mkii motor until i had time to do a rebuild on the motor.

Pulled pan, second gear has chipped teeth and worn dogs, tried a third motor from a 79 A3, same thing no 2nd gear.

Guess that means time to split cases, change trans, cam chain and guides (one has a piece of guide floating around in pan) and do a full refresh

second gear wheelies kills alot of them.

leon

Thats funny!!!! Started selling 2nd and 5th OP shaft gears back in early 1976. It was the first time the dealership I worked at sold any trans parts for the Z1/KZ motor. By the end of that same year we were selling the shifting fork for 5th, complete shift drum, and those two gears on a weekly basis!! Then about a year or two later we started selling output shaft bearings too.

I still till this day can rattle off all those trans part numbers along with all the bottom end gasket and o-ring part numbers. After a few months, I never even bothered to look the part numbers anymore. I would just go and grab the parts from their parts boxes!!! It got real old real quick explaining to a customer why he needed 2nd and 5th when it dropped out of 2nd not 5th!!! God I made some good money off all those dummies that powershifted leaving every stop light in town!!!!

Well the only motor that had 2nd at all lost it within a hundred miles or so (didnt get to beat on it really) and being mkii motors i figured the other two would be good to go.

So far I have 3 1000's with not one good tranny out of the bunch, the only one i've had that actually had all its gears was the j model

As long as you did not powershift, a stock motored Z1/KZ trans was near bulletproof!! Now drag bikes, and turbo bikes were a little harder on the trans gears. But all most people did was get the dogs undercut.

All the Z1/KZ900/ KZ1000 (73~80) trans gears are all the same. Only difference in all the transmissions is the 79/80 output shaft is a bit longer. Those are the shafts that use the shouldered counter sprocket nut, and the lock tab has the spline pattern on the ID of it.

Back in the day you could buy a complete close ratio transmission with both shafts for like 180 dollars for the KZ motor from Kawasaki. 13254-001, was the part number on the box. All it said in the price book was "mission assy". Yoshimura sold that same trans for over 600 dollars, but it came in a Kawasaki box with that part number on it!!! Plus all the dogs were undercut from the factory. GREAT road race trans!!!

Well apparently someone in Indiana Illinois and Michigan don't know about that near bulletproof statement. Getting some sticker shock from ebay on transmission parts. Looking like a small buttload of cash in parts, gonna have to wait and do it right back to the little 550 for now i guess.

And i just finally got the chance to ride this bike, getting it to idle right alone was a pain.

Dr. Gamma wrote: As long as you did not powershift, a stock motored Z1/KZ trans was near bulletproof!! Now drag bikes, and turbo bikes were a little harder on the trans gears. But all most people did was get the dogs undercut.

All the Z1/KZ900/ KZ1000 (73~80) trans gears are all the same. Only difference in all the transmissions is the 79/80 output shaft is a bit longer. Those are the shafts that use the shouldered counter sprocket nut, and the lock tab has the spline pattern on the ID of it.

Back in the day you could buy a complete close ratio transmission with both shafts for like 180 dollars for the KZ motor from Kawasaki. 13254-001, was the part number on the box. All it said in the price book was "mission assy". Yoshimura sold that same trans for over 600 dollars, but it came in a Kawasaki box with that part number on it!!! Plus all the dogs were undercut from the factory. GREAT road race trans!!!

Sorry to question your knowledge dr. But not all z1/900/1000 gears are the same.Didnt the 1980 mk11 motors and maybe some of the 79s, had a wider contact patch on the gears. I know when i built my motor i had the wider contact patchs. Also if your going to rebuid one of the engines and didnt have to have factory, i would rebuild the mk11 motor. If its a 79 it could be a toss up. Some of the 79s had mk11 cases but kz internals. The 1980s where all mk11 motors. They had the bigger trans gears, bigger 1016 16 tooth center cranks. They had stronger cases along with a few other diffrences like cam chain link length and charging diffrences. The mk11s are deffitenly stronger motors stock.

Go check your Kawasaki part numbers on some old mircofishe, or even the part numbers on Kawasaki.com. From 1973 (Z1) to 1980 (KZ1000A3A) It is the SAME part numbers gear by gear. How would you order the "wider" gears if the part numbers are the same?? Don't think you can call Japan and ask to order some of them special wider MK II gears!! Now if you ran across a bike with the close ratio trans kit, those gears look a little different than the standard trans gears, plus most of the ratios are different for each gear too. If the gears were wider or changed in any way. the would have a different part number. The MK II output shaft, and shift drum are a tad different but they will fit the early model motors.

I can't see the factory in Japan ever making a run of "special" gears just for a production run of MK II's. Thats not how the Japanese manufacturers work. I can remember when the Z1R (KZ1000D1) came out everybody said it had a close ratio transmission. WRONG just a rumor. You can take a '73 Z1 trans and drop it into a '80 MK II case and vise versa.

Yes the cases are thicker in places, and the crank is stronger and has a bigger 16t center pin. Plus the camchain is 124 link and the cam gears have 2 more tooth on them. But the cams are the same part number for a '76 KZ900 as for the MK II's!!!

never said the cams were diffrent but iam pretty sure that some of the trans gears in deed did have a lip that made the contact pattern wider than on others. The gear ratio is probably the same but the have a wider contact patch.

Here take a look at this. I know when i built my motor. I had a very reputable guy tell me that the trans i had i didnt want and proceeded to tell me and show me the diffrence and there is.
kzrider.com/forum/2-engine/368399-z1900-vs-kz1000-transmission check that out.

Also i know they did use stuff for limited runs like the crank, The alternator which is completly diffrent than a 78 and lower. So there is stuff they only used for short runs.

Fat guys and missed shifts kill second gears. Any project I have now I pull the pan and look at the trans before I use it. Easy to see when you know what your looking for and alot less trouble to find it early.

Or, you can just take that transmission out and buy the billet gear parts from APE and send them out to get back cut. Take that crank and also have it indexed and welded, not cause you need it but for good insurance, besides a balanced crank and pistons frees up the HP you have already, think of it as a balanced load in the washing machine vs a load that is unbalanced and you get the idea. Then, later if you decide, 1075 and nice cams would be perfect or can go big on top and not worry about down below if it can handle that power. Nothing wrong with that.
The gears get worn out from people who don't know how to shift, from beating on it as second gear is the money shot gear and gets the most use and usable power, and well, if the gears are backcut they lock together much more easier and can take more power without slipping out. If you are going to split the cases might as well spend a little on the stuff that improves it, no?
It's only time and money. I'd try and find a MKII motor as the webbing on the case is stronger and get stuff you can build up that is already strong. Not saying that any other motor is less but Kawi did improve things and made them better in 80 than in 73. Take the best and blend it all together.
I would like to add that I have broken many a second gears but never in a kz and I have beat on my 79 and my 80, well over 20k miles easy on both bikes in two separate seasons each. I have never been easy on my bikes but I have always religiously maintained them. I can say that these are the best bikes I have ever owned. I have broken second gear from just redlining my zr1100 and I know that everyone and their brother's have done the same as well. They were known for weak trans since new. I always shifted smoothly but usually always ran up to redline before shifting. I either hit a pothole or it just bent the fork and jumped out of gear. Either way second was gone. My midnight special was worse. I shifted from second to first and it just got all crazy jumping up and down a few times before I was able to do anything about it. It went about 5k miles later. So, some bikes are known for their weak second and some have just been abused. Kaws usually have been abused for that gear to go out.