Help Needed to Identify Worn Transmission Parts

[bpdinse]

Hello all. I recently purchased a 1964 Honda CA77 that was cosmetically in excellent / original condition. After a carb rebuild and un-sticking the clutch plates, I found that second gear would not engage – it made grinding noises when driving down the road and trying to shift into it. Then it would simply not engage. No problems with third, fourth, and first. Shifting into neutral is no problem either. So, after reading here on-line and talking to LM, I came to the quick conclusion that I had some worn transmission parts and needed to get into the lower half of the engine case to see what was going on. Since this is the first time I have worked on one of these engines, I decided to get a second engine for both parts and experience. I tore into this one first. The problem motor is still on my bike.

I wanted to ask for some feedback from all you experts out there as to what is worn and needs replacing on this transmission. Again, it is not my engine that has a known second gear problem (that one will come in another week or so). I am trying to build experience and knowledge before getting into the other running engine.

From what I see here, I see worn shift forks. The darker color one that sits on the left side when the engine is inverted, looks worn. It is nearly flat. Is this one too worn and in need of replacement? The right shift fork has less wear. Is this one still good?

The shift drum channel looks okay to me in that I see no wear or shiny parts. Does the shift drum look okay?

The gear teeth look good to me. Does anyone see anything there?

The dogs have some bright spots on the flat surfaces but I don’t see any rounded ends. Not sure what to look for here. Anyone see anything worn here?

The dog engagement on second gear looks like it is at ~40%. Does this look normal?

Any other comments?

I have no idea how this transmission actually performs since I pulled it out of an engine with a seized piston. Interestingly, the engine case is a CA77E s/n (1964) but the head is a CB with two carb ports and the 180 cam/crank. The clutch has the metal centered friction plates so that is not a 1964. It looks like someone either put a CA77 case around a CB engine or used the lower end of a CA and upper end of a CB. I am not sure if I can use parts from this transmission due to this but I’ll look all that up. For now, I just wanted to learn something by getting your feedback on the questions above.

Thank you kindly in advance.

Best Regards, Brian

EDIT: I may have gotten the gears wrong - what I am calling first, second, third, fourth may actually be fourth, third, second, first. I'm sure someone will tell me - I am brand new to all of this!)

[bpdinse]

Here are more pictures...

[bpdinse]

Here are the rest of the pictures...

[rustywrench]

Brian,
I don't see excessive wear on the forks here, but I do see dogs worn on the engaging gear, power side. By that I mean that the engagement contact point with power on will round the dogs on the corners. These don't seem too bad but I would try to get a little more engagement on the dogs. I like 75% or more. Offset cotters can do the job to move the gears in closer. We can cover that in more detail later.
You are correct that you got the numbers reversed. Upper left is 4Th and lower right is 1st. Look at the first gear and check the side to side movement of the gear. If it wiggles a little,OK. Too much play and you have a worn brass bushing that the gear rides on.

As for your other second gear, I'm thinking maybe a bent fork or really bad dogs.These transmissions have a way of hanging up when you shift softly and then folks bang on the shifter with too much authority and bend things inside.

Kudos to you for opening an exploratory tranny to learn on. You are well on your way.Keep us posted on your progress. Rusty

[bpdinse]

Rusty,
Thank you for the feedback! I am very interested to get into my other engine now.

After your feedback on the dogs in the pictures I attached, I went and looked at other posts with pictures of transmissions. I see that the dogs in some show sharp corners while the ones I posted are not sharp - slightly rounded, rather. I now have a better feel for what they should look like.

I'd like to understand more about the offset cotters. I can wait until I have the actual pictures of my problematic transmission. I understand the concept just not sure of the actual implementation (different thicknesses to choose from? things to look for/consider? where to get them?).

I am also interested in crossing (or X'ing) the gears. Most of what I read had to do with a CB or CL. I think I only came across one post on X'ing the gears of a CA. It is not clear to me if I should do this and how on the CA that I have (I read one "yes" and one "no"). But the trans will be apart so I might as well do it if there is an advantage.

Thanks for the encouragement as well! I don't want to mess things up. The engine on my complete CA77 is in good cosmetic shape so I wanted to get a feel for things before working on the nicer engine. I think I am ready for that now.

Thanks,
Brian

[rustywrench]

Brian,
Good observation on the dogs. If I were to try to use this tranny, the dogs I would consider marginal. Usable but I would not expect much for very long.

I can't tell you about x'ing on the ca but I think the general opinion is not on the ca cuz of the longer legs on this bike. Makes a world of difference on the others though.


Keep up the good work,,,,,,,,,Rusty