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Discussion Starter · #1 ·
I replaced my engine with a used one due to a 3rd gear failure at approx. 60,000 miles.
Now I am experiencing the same issue with my used engine a1000 miles after installation. It was said to have approx 25000 miles when I purchased it and installed it.
I do not abuse 3rd gear but I do lots of clutch-ups in 1st and 2nd gears.

Is this a common issue for this transmission?
If I tear it down to repair should I replace with stock parts or is there a better option?

I thank you guys in advance for any comments, thoughts or ideas regarding this issue.
 

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if u go to open it.. then i would just replace the gears.. open for one thing is a waist of time.. fix everything u feel needs to be, that way u feel more confident in your motor!
 

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The transmission issue on the '98 and '99 is a third and fourth gear issue. I rebuilt a bike with a catastrophic failure, but my bike which I bought new had a minor issue with 3rd gear. The '98 and '99 has third and fourth on the output shaft on a common bearing with a small snap ring outside each gear. This causes any thrust on either gear, due to worn dogs, to push on the small snap ring behind the other gear. The single bearing set-up with two snap rings allows the gears get a bit sloppy and let them slip until engaging fully, this is what happened to the transmission in the bike I bought new. Now the bike I rebuilt, the snap rings had been pushed completely out of grooves allowing third and fourth to be completely loose and grinding things all to hell. The 2000's and newer have seperate bearings for third and fourth and use three snap rings, the third one is between the gears, which are much heavier than '98 and '99. As far as I'm concerned if the bike is babied it will last fine but there are only so many hard 2nd to 3rd upshifts the tranny will take.
from http://www.kawiforums.com/zx-9r/90005-1998-zx9-good-bad.html

I have 22k mi and no issues yet...keeping an eye on 2000 tranny prices on ebay tho and gonna scoop one up when the right deal comes along just in case lol (another poster commented he knows a 98 with over 100k mi and no issues)
 

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Man, I have my engine out of my bike with the head off. If I had the money, I would rebuild it. I do know that the shifter can get sticky too and cause some problems when shifting. I.e. invisible neutral. Take off you foot peg and gear shifter. Take them apart and.clean and re grease. Mine was sticky and did not have much to little lube left.

To some people its a rocket.
To others it's freedom. (zx9r)
 

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Discussion Starter · #5 ·
So from what I’ve found out so far …I can do a repair to the poor design which will effectively make it as good as the newer designs ( 2000 and up).
Apparently the design issue is that 3rd dwags to 5th and the engagement is only about 1mm which then decreases as wear happens on the shifter fork and the circlips / spacers.

The fix is basically replacing the gear bearing to a two piece , installing more spacers and adding a new circlip. I found the details on another forum. I’ve discussed this with a well known machinist and he has been involved with this fix before, he also suggests undercutting the gear while we are there to assist with the engagement.

Now my issue is splitiing the engine….do I need to pull the cylinders etc?
Do I need to pull the flywheel / rotor..?

I’m hoping somebody can give me the basics to getting into the tranny shafts quickly with minimal teardown / strip….?

Thanks again all
 

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Dont kno but do you have a manual? Should tell ya. Im mobile now and cant search but posted the link to the thread with the manual in one of Clapps' threads in this forum not too long ago. The original thread is 2 years old.
 

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Anytime you have to get to the shift forks, drum, or gears you have to split the cases.
 

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Here is a link to my drop box for the Manuel.

http://db.tt/IQp2d3vG

To some people its a rocket.
To others it's freedom. (zx9r)
 

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I think it would be easier to just replace the setup with the traditional 2000+ gears or 06-09 z1000's myself.. at least its proven to work well, and great shifts.
Havent read much about using a 2 piece bearing and more clips.. let us know how you make out.
 
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