Splitting casses on '80 KZ 1000

My '80 KZ 1000G is jumping out of 2nd gear under hard acceleration. I have tried all the easy stuff like new detent arm & spring, and an overshift bushing but it still jumps out. My conclusion is that 2nd gear needs replacing or under cutting. I asume that I will have to split the cases. My question is, can I remove the engine, turn it upside down and remove the bottom half with out removing the top end? I just did a top end last winter, wish I'd have known about the tranny problem then, but bike wasn't running when I got it. Any help will be appreciated. Thanks in advance. Fasstdave61

Yes you can do that

I'd start with a shift fork change and you can do that without splitting cases. Pull the counter shaft sprocket (front sprocket) and the cover plate like you would to install the overshift bushing. Drop the oil pan. From that point you'll see how to go about it.

Les

Les: Thanks so much for your reply. I will try new forks, hope that does it, don't want to split the cases. This site is great, its been a lot of help.

Fastdave61

I'd replace all gears associated with 2nd gear. The gear dogs(gear locking tabs that lock with the other gear) get worn and no longer have a sharp edge allowing it to slip off and pop out of gear.

If you only replace one gear, you're doing it wrong so to speak. Replace the clips that you take off to remove the gears as well, once they are sprung, they dont fit as tight.
Also replace the shift fork associated with 2nd gear. If you miss a bad part, you'll be doing it again soon.

P.S. use 1104 or kawasaki bond on the cases for reseal.I use it on all covers even ones with gaskets, guarantees no leaks.

Sounds as so you will need to split the crank-cases. The trouble will probably be the rounding of the engaging pegs on fifth gear.
To save confusion the gears in trouble will probably be on the "Sprocket" shaft, also known as the "lay" shaft and/ or the "Output" shaft.

The gears in trouble are both the second gear, which is at the end closest to the sprocket ball-bearing end and the fifth gear which is the next to it.

On inspection you should notice a rounding of the pegs on the fifth gear and possible a rounding of the edge of the oval holes in second gear. If there is too much clearance (end-float) you may be able to use a slightly bigger "thick" washers (which are usually approx 4mm), which is between the above mentioned ball-bearing and second gear.

RegardZ.
PS. you can do this job without removing the head or cam cover. Also, just read the bike wasn't running when you obtained it. You will have to do a detailed check of the position of all spacers, particularly the "Thick" washer.

If the dogs are worn and you gotta replace the gears. I would just a whole other trans and have it back cut. And if i was you id get another mk11 trans there stronger. The mk11 have the a step on the gears unlike the earlier models.

Looking at the manual i can't see any reason why you can't split with the top end in tact, i used to do that with my CB7504, as for jumping out of gear, possibly worn dogs or bent selector fork or combination of both