TOPIC:

hi, just purchased a 1980 z1000 of ebay, but it has a serious gear problem ( can only select 1st and neutral), ive whipped off the transmission cover and sump and removed the layshaft selector forks which arnt bent, the problem seems to lie around the sliding 4th gear- it wont let the selector drum rotate, however ive never worked on a big bike gearbox before so im not sure - any information on gearbox layout would be greatly appreciated, also is it possible to split the crank cases with the engine upside down without first removing the top-end ( dont know if theres any hidden bolts on top).......please help, i need this zed roaring down the road- soon, cheers mat.

Hopefully you are just dealing with the often-discussed KZ neutral finder feature. Briefly: you can't shift into second unless the engine is running. Hope that's your deal - check out this thread:

kzrider.com/component/option,com_joomlab...atid,2/id,3344/#3344

There are no bolts on top. You can split with top end still on. Ditto on hoping it is just the neutral finder balls. Engine must be spinning to get into 2nd gear.

RomSpaceKnight wrote:

There are no bolts on top. You can split with top end still on. Ditto on hoping it is just the neutral finder balls. Engine must be spinning to get into 2nd gear.

Rom:
I apologize for correcting you. I know what you meant. However, the author of the post may not so---
The output shaft also has to be turning.
Harry

so as i have the engine now - with transmission cover and sprocket off -if i remove plugs and spin engine with starter 2nd gear should then engege directly from first missing neutral ? cheers mat
also i was told when i bought the bike that third slipped when engine is revved hard could you tell me whether this is likely to be the selector fork or worn dogs, or anything else, thanx again

The engine turning over is not relevant, the part that has to be spinning is your output shaft. Spin your countershaft sprocket as you try to shift into second.

The other guys are correct the output shaft must turn. Sorry for confusion That is what I meant.

I knew better than to unsticky that thread

hello again, been tinkering with gearbox this morn b4 work- still cant get 2nd to select- the sliding 4th gear pinion just wont move far enough down the shaft to allow the fork and selector into position, so a couple more questions for you buffs:
-how fast does the output shaft have to be turning to disable the neatral finder feature;
-how far should the sliding 4th pinion move on shaft (mine moves down from against 1st until its free to rotate but it doesnt butt up aganst 3rd - this is the position it would have to take if the selector fork was on it and i changed to 2nd);
-should both selector forks for the layshaft be identical (labeled T-8)
im not sure if the previous owner had some dodgey work done on gearbox (i know there is a problem with 3rd) so im exploring all avenues, cheers again- mat

I gave it a pretty good spin with my fingers to get it to shift into second. You have to spin it fast enough that centrifical force throws the balls out of the holes in the shaft.

battymatty... It is sort of hard to screw up putting the shift forks in place when installing the lower case onto the upper case. I suspect your bike will shift just fine once running. There is a positive neutral finding feature that uses a ball bearing that MUST be spun out of a detent (countershaft) and I doubt you have spun fast enough to get it into 2nd gear. What is stopping you from starting the engine and trying to ride the bike to see if it shifts?

Now to answer your question... If you pull the engine to split the cases without removing your top end, you can do this but ALL engine covers have to come off which means a gasket set and scraping. You have to remove the stator cover, inner countershaft cover, kicker cover, clutch cover, inner points cover... the marriage line for the split occurs under those covers and new gaskets will be needed. You will want to replace the rubber plug on the stator cover if it seems moist with oil at this time as well and replace your engine seals which all fit into case covers. Jeff at z1enterprises.com sells seal kits. Once you pull the engine, I use a furniture moving dolly and flip it over after removing the top five case bolts. These are the ones located around the starter area. Then there are 17 lower bolts. Most are 6mm (10mm head) but the ones in the crank area are 8mm. You will need a torque wrench and the torque specs for all the bolts, you will need to also buy some semi-hardening gasket maker (I use Hondabond HT). I run a tap down all the bolt holes so it takes me a tad longer. It really helps to run a tap down the three threaded holes (8mm 1.25 pitch) used for splitting the cases, especially if the cases have ever been painted. These holes tend to crud up and make turning the 8mm bolts you will need to use to split the cases very difficult otherwise. There are two holes in the front of the engine and at least one in the back. I use socket head bolts and when you screw them in, the cases split easily and no banging is needed. Once you pull the lower case off, the transmission can be lifted out as a unit. Pay attention to the shift fork placement and do this while the bike is in neutral. You just drop the new transmission assembly in and button it up the way it comes apart. Oh yeah, the oil pump needs to be removed. Pay attention to not lose the oring between the cases. Also, there is at least one locating C shaped deal that sits on the big end of the cases under the transmission. This will usually just sit on the case when you lift the transmission off but it can stick to the transmission and you won't notice it. It is about ~2mm thick and about 30mm long and shaped in a C and just sits under the transmission. You will need to also re-engage the kicker but it only goes in one way. Don't force the lower case back on... it will fit easily back on if everything is in place properly. Once you have the lower case back on, the only "gotcha" is the kicker itself. Get the engine back in. Then, slide the kick start arm on the splined shaft and rotate the kicker down as far as it can go. This locates the kicker gear stop internally. Then put the spring on first twisting the spring around the shaft counter clockwise. THEN slide in the plastic or aluminim spacer. Check that the kicker returns properly before putting the cover back on. That is about all I can recall from memory... I haven't split any cases with the top end on for a couple months now.