Hello - Finally working on my CT-1 gearbox - replacing the small 2nd gear pinion and wheel, and same for the 5th gear.  Tear down and re-assy seems to make sense but on the "main axle", all the gears are held on by 2nd gear - which appears simply pressed on.  Anyone have tricks to pull the gear...or reinstall a new one later?  If using a puller it would need to be tiny to get into position.
Thanks, JoeM 

Gotta press it of by supporting under the big gear in front of it. Just hope it goes back on as tight as it comes off. Pressing it on can be a headache trying to get running clearance plus a whisker. I used to tension the press up to almost moving guessing by feel-- knowing my press at work-- then belt the press base or bench with a copper hammer to move it incrementally. I do that with crank assemblies too. Sorry i'm over complicating it. Could just smack it off with a copper hammer while supporting the big gear. Na better not teach bad habits.

I'd probably replace the shaft too if pressing off the gear. 

I expanded the pic & little gear looks a bit chewed. Or it's my computer screen. If so, you might pick up a complete good trans for very little. Not sure what he difference is 'if any' between years up to "73, or 125 as well.

Thanks for the comments guys.  Yes, the small gear in lower right (2nd gear pinion) is spalled up pretty well so I bought a new one and its larger mate.  For what ever reason, 1st gears are fine.  My smaller 5th gear had a broken dog so also got a new one of those...but now thinking about getting its mate just because.  Also replacing the small "thrust" washers.
Regarding buying an entire surplus box of parts....always worried about same issues...but guess could get lucky.
I'll report again after I pull the 2nd gear..
Regards, Joe

Talking broken dogs. Just be sure the selector drum is ok & not broken the end off from a derailed chain bunching around the front sprocket. Smacks the end off inside the three screw cover. Then the drum cam float to the right & compromise the doggies & they get knotted, so something has to give.

It doesn't seem like you can pull off 2nd gear by putting the puller on the adjacent gear because there is a circlip in between.  See in diagram?  Looks like the only way to remove 2nd gear is with for tiny jaws and a lot of heat, true?
Regards,
Joe

I said in an earlier post that you need to press it off supported under the next gear along--the big gear. Sounds like you don't have means to press it of so shock treatment is how i'd do it. If you have a good vice & can sit it along to one end so the shaft drops down & clears, then bring the jaws up close--or if you feel the sliding gear is in the way & cant get far enough under the big gear for safe support--find two very solid steel pieces to slide in close to the gear across the vice jaws. Don't directly hit the shaft but use a block of solid alloy or copper & a 'bloody big hammer'. Just don't miss & hit yourself. I've never heated one but i 'think' heating it would heat the shaft also & may not have the desired affect. That's just my own ideas!!. To refit i'd go the same way. But then again freezing the shaft & warming the gear could work as i've seen others say when fitting bearings, which is slightly different, but!!.

I'm confused....so if I position the assy vertically so splined end is down, How possible to support under the ajacent gear (5th gear, (which is #6 in the parts diagram) and drive down on the small shaft end, because the oposing force will be halted by the circlip between the two gears.  And all the remaining parts, and another hidden circlip, can't be removed from the splined end because they are captured by 1st gear machined into the shaft, true?  Try explaining how to do it again please, but go slow and say where the two forces (supporting and push or pull) will go.
Thanks!
Joe 

Thats interesing as shouldn't be a circlip there. I'll go & have a think. Ok, had a think--that didn't help. Looks like i must be wrong which totaly stuffs all my theories, or they've drawn it wrong. I there's a circlip it must be visible. Still don't don't think it has one. So if you see one can you get in there & butcher it out of the groove then revert to my method. Every pic online shows as you say but--but but i dunno. I'll keep looking for a dismantled shaft online.