Gearbox / Transmission Differences

[jnnngs]

Hi,

Just rebuilding an engine and noticed some differences in a couple of different gearbox countershafts I have.

See attached photos.

20181005_135728.jpg

20181005_135734.jpg

20181005_135748.jpg

In the pictures, the left countershaft came out of a Z, the right one I picked up with some other spares, not sure what bike it came from (but looked like a CBX one). There are some big differences:
- on the countershaft itself, the left one has a hole drilled in the top, the right one doesn't
- also, the cutouts in the 1st gear are very different shapes
- the dogs on the next gear (5th) are different - oval vs. circular
- and the cut outs on the next gear (3rd) are different shapes again.

I had thought that the right hand countershaft may be off a prolink, but according to the parts manual, the countershaft itself is different to a Z, but all the gears are the same. So that doesn't explain it - any idea what bike it's off?

I also noticed differences in three countershaft 4th gears I had when trying to align the oil holes when re-assembling:

20181005_155658.jpg

20181005_155705.jpg

20181005_155713.jpg

Notice how the internal machining is different - the slots that mate with the countershaft all vary relative to the gearbox dogs. The oil holes are all drilled in the same place, so it means that when you assemble them the holes don't line up with the corresponding oil hole in the countershaft. For two of the gears, the holes are close, for one it doesn't line up at all.

Why would they be different?

Paul.

[jnnngs]

Hi,

Anyone got any ideas on the above?

Are prolink gearbox internals different to earlier models?

Paul.

[daves79x]

The only difference I've ever seen or heard of in CBX transmissions is in the shift forks. The later ones have a better design. I'd say you have some non-CBX parts there. Someone else may have a different opinion.

Dave

[tevan]

The only difference I've ever seen or heard of in CBX transmissions is in the shift forks. The later ones have a better design. I'd say you have some non-CBX parts there. Someone else may have a different opinion.

Dave

I would bet anybody if Dave said this it is the gospel. He knows these bikes more then anybody hands down.

[jnnngs]

The only difference I've ever seen or heard of in CBX transmissions is in the shift forks. The later ones have a better design. I'd say you have some non-CBX parts there. Someone else may have a different opinion.

Dave

Thanks Dave. Maybe off a CB900 or something, very similar to the CBX countershaft.

The other point I raised on the oil holes not lining up - they are all Z countershafts which have been machined differently. Very strange.

Paul.