Thanks for the highly detailed description of how this works.
I’ll get back in this next week. I was moving shift lever up/ down while rotating the rear wheel on a stand.
I was really hoping that I didn’t have to split the cases since at first it seemed intermittent . This bike hasn’t ever been apart at all and was hoping to leave it that way. I was only going to use it for puttin around. Now I need to rethink this.
Thanks!

There's a lot more I'd try before splitting cases.

What I would do is remove the linkage and try to rotate the shift drum into each gear. You'll probably need to remove the shift detent plunger because otherwise you won't be able to rotate the drum very easily. Without the plunger/spring, it won't "snap" into gear. By turning the shafts and the drum you should be able to rotate the drum through all the gears... They don't shift through the gears easily like this... it's fiddly... and you can hit false neutrals... but you should be able to do it by rotating the rear wheel and/or input shaft as you rotate the drum.

The intermittent problem is often the shift detent plunger/spring... so you could also install it and make sure it helps "snap" the shift drum into gear. It doesn't seem such a simple part could cause a problem like this, but it does. Maybe something has happened to where it's sticking in the bore? Seen that. I also had one once where someone put the wrong spring in there and plunger wasn't even contacting the shift drum.

Also check the manual. I'm seeing the gaps between the stop pin and the limiting plate on the shift input shaft don't look too equal on your bike... could be camera angle... We can't see the gaps between the "claw" and the shift drum pins which is actually what you need to be concerned about. And then the manual shows a second adjustment to check at full travel. It's been many years since I messed with one of those but I do remember a friend having trouble after a crash and it took a bunch of tweaking the adjustment to get it to shift right again. (We didn't have a manual)





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Thanks Mark that does make me feel better about this. Then again I paid 400.00 for it, so I think that was a good deal?

When you saw the bore on detent plunger, what was wrong and what fixed it? Could the spring be worn and not be applying enough pressure?

Plunger and hole was crudded up and was sticking in the bore. Just cleaned everything.

Spring could be wrong one. You said it all looked good though. If you pull the linkage you'll be able to easily tell if plunger is working... it locks the drum into gear and takes effort to rotate shift drum. Without plunger, shift drum rotates relatively easy... note that I didn't say it would shift easy... still need to rotate shafts to get the dogs to engage the slots.

Could be adjustment issue or something bent/damaged in the shift linkage. I'm surprised the gaps to the stop pin look so uneven like I showed with the lines I drew on your picture.

I’ll check the distance and pull the shift shaft out and see if I can get some gears to change .

I know from what you said about the shafts turning and gears changing, but if they don’t change (gears) that would mean a stuck shift fork or something ?
Thanks in advance

I pulled the shift shaft out of the way and the claw so I could turn the shift drum with a screw driver. I also pulled the plunger out . While trying to turn the shift drum with the Phillips screw driver I can see shift fork trying to move the gear over. Unfortunately it’s still only moves same amount as it was together. I’m turning rear wheel at same time , so everything is turning. Something I’m not doing?

With it completely apart the shift drum should rotate easily? Mine only moves a little back and forth very little. I think something has gone wrong internally.

Sounds like my issue/similar but my bike has been sitting for many years.

I’ll probably end up splitting the case to see what the issue is. I was hoping not to.


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I wouldn't say it should turn "easy"... nor would I say "hard". I just grab the drum and jiggle/turn it while rotating shafts. Not sure if a screwdriver would turn the drum. Try turning it both ways too... you could be in first and at the end of the slots for that direction of rotation.

Look at a picture of a shift drum... the forks are pushed side to side by the grooves as the drum turns.

So as I try to turn the drum , it moves less than 1/4 turn. As I peer inside I see the shift fork on both shafts try to move their gears. How much should a proper shift drum move in either direction?