Topic: K7/8 Transmission Gears in K0

[70CB750]

If you recall, Dorothy's main problem was the 2nd gear jumping out - I rode her 1,3,4,5 for two years or so

I have a set of gears from K7/8 - thanks again, Larry - they are in much better shape than originals.

Would there be any problem swapping all the K0 gears for K7/8?   

[MoMo]

   You're welcome, hope you can make use of them and good to see the old girl getting some attention...Larry

[754]

Use your old sprocket shaft.
 Make sure the 2 gears driving it match.. ie, not a 78 one and a 71 one.. different teeth count.

[70CB750]

Thank you, Frank.

I was tempted to go with the newer output since it has wider bearing, but I can still swap that.

[Stev-o]

I was tempted to go with the newer output since it has wider bearing, but I can still swap that.

The ouput shaft is longer on the later models [10mm?] and would cause drive chain misalignment.

[70CB750]

I was tempted to go with the newer output since it has wider bearing, but I can still swap that.

The ouput shaft is longer on the later models [10mm?] and would cause drive chain misalignment.

Yes, you are correct.  I have a Suzuki aluminum swingarm I want to use - will have to see how it all lines up.

[754]

73 and up have wider bearing.
 If you run the other swingarm, and with your skills you can probably run long shaft.
 But requires late carrier on the back  or modding yours.. i did mine  a few moths ago.

[Stev-o]

 But requires late carrier on the back  or modding yours.. i did mine  a few moths ago.

How did you mod the carrier, Frank?   

My current [stalled] project is a K5 frame with a late model motor.

[754]

Short version,
I backed the studs out about  5/16.. that took heat
Then I made 4 spacers  about .375 long , could make it out of 1 pcs of 3/8 plates but
Sprocket now has nothing to center it, so to do properly , put carrier in lathe , dial original lip, then turn the part where sprocket will sit and sleeve it.
 I put 1/4 inch of spacer on sprocket side, will make a 1 piece soon. And i wil, bump swingarm out slightly, hard to get the 1/4 inch in small notch on swingarm.
 You will have chainguard issues likely and  moving shock out slightly would help. Some type shocks have less clearance to chainguard.
 None of that is hard to do on a lathe, or you could go late swingarm but then shock should be spaced, and you will  be 1,25 inch longer.. that may affect fender and seat..

[Don R]

 I put a gs1100E swingarm on my kz1000. Before I bolted it on I checked it against a cb one and it appears to fit fairly closely. Good luck.
 I have a 78 backcut super sport trans to go in my K2 dragbike but I'll most likely use a 78F crankcase now. 

[70CB750]

K0 output shaft next to K7/8.    They look the same length to me.  Puzzled.

Also, there are no grooves in bearings on the right one, how is it secured in the case?

[754]

The adjustable oiler bolt s, i think is bigger than the thread in the end of K7/8 shaft, and I think no clip groove m if I remember right. And a different gear count if it was not swapped.
 The right hand shaft may he a K3-K6 which is fine.

[scottly]

The K7/8 shaft doesn't have a groove for the splined plate that locates the sprocket; it has a shoulder the sprocket sits against, with a single bolt in the center with a washer to clamp it against the shoulder. Notice how the K7/8 seal is mounted further out in the case; the case sticks out in that area, while the earlier case is flat.

[70CB750]

I guess this output shaft is older than??

But how come bearings have no grooves?  I know the axial forces are very small but still, what prevents the shaft from walking out, bearings and all?

[MoMo]

think there was a ridge outside the case that kept it in place.

[754]

78 case looks like this, can't tell what us a riidge in there.

[70CB750]

The K7/8 shaft doesn't have a groove for the splined plate that locates the sprocket; it has a shoulder the sprocket sits against, with a single bolt in the center with a washer to clamp it against the shoulder. Notice how the K7/8 seal is mounted further out in the case; the case sticks out in that area, while the earlier case is flat.

Yes, thats what Red output shaft looks like - 78SS.

[HondaMan]

K0 output shaft next to K7/8.    They look the same length to me.  Puzzled.

Also, there are no grooves in bearings on the right one, how is it secured in the case?

The shaft's shoulder is in a different place on the later ones, to allow for use of the wider late bearings.
I doubt the later shaft will fit: while I have occasionally found them mixed in the cases, they were mixed by Honda, who also cut multiple grooves into the cases to received the retainers. They come in versions like the 2 you show here, plus 2 more, one which has a grooved output bearing for a retainer (like on the mainshaft bearings). The cases used determine which output shaft/bearing set will fit.