Shifting issue

[tahoethumper]

I’m still on the homestretch of my Super Rat rebuild before I put it back in the frame, and I’m finding that the only shift I’m having an issue with is from 5th to 4th. The rest of the shift pattern is good. In order for me to get out of 5th and down to 4th is if I just grab a hold of the end of the control shaft and slightly help pull it outward while engaging the shift lever. It then pops out 5th and functions fine.
I messed around with the “measuring” method of the shifter arm and got it close, and then proceeded with the “trial and error” method to the point where it shifted as good as it could. I should also note that upon engine reassembly I inspected the control shaft and control shaft springs, and found none of them to be broken or collapsed, nor was the shaft bent.
Any suggestions as to what I should try and do?
Thanks.

[Bullfrog]

You have bumped into a symptom which seems to show up ONLY when there is excessive free play/wear/"slop" in the shifting mechanism in the shifter cover. The extra wear lets the shifter components move to "non-designed" relationships and they simply can't pull the control shaft back "out" of the 5th gear position. It is time for a shift cover rebuild.

NOTE: There is an "emergency"/short term "fix" which can get you back into normal operation for a while. A small "O"-ring can be stretched and fitted into position between the control shaft spool and the end of the counter shaft. The "O"-ring serves to limit (by a teensy bit) how far the control shaft can go "in" . . . and that little factor may get you going for a while. (I first heard of this tip from super-go-fast Hodaka racer, Jay Lael.) If I remember correctly, the "O"-ring must be made of 1/16" or smaller diameter material. Mayhaps Jay will jump in here if I've got that wrong.
Ed

[tahoethumper]

Ed, that is a very interesting, temporary fix. It makes sense that an o-ring would act as a stopper and prevent the control shaft from going in too far. Is the excessive play caused by the end of the shifter arm wearing smaller, or by the slot on the ratchet wearing larger, or both? I would be more inclined to replace the part that has failed rather than all of the components. Which parts would you replace on a rebuild? Thanks again!

[socalhodaka]

I’m almost done with a new video of Greg(California Hodaka) rebushing a shift cover with a new and improved bushing that he and Jamie McAdams came up with. It will be done in a couple days.

[DG29]

Kelly hit the nail on the head. Where the shaft slides through on the cover is the part that fails. It is many times well worn and the cover can even be cracked on the inside causing the bore to be even larger. The permanent fix is to machine the cover to accept a bushing and then machine that bushing to the proper size. I did one in my neighbors garge/machine shop a few years back. Most recently I had another one done by Greg at California Hodaka. If the proper bushing material is used the shifter cover will never have the issue again.
Just my .02

[Bullfrog]

I have a slightly different view of things. I fully agree that excessive wear of the foot change shaft bore is BY FAR the most common cause of shifting problems. However, excessive wear of other components can cause the symptom which was described at the start of this thread. In fact, my memory is that Jay experienced that exact symptom with a shifter case which had just been re-bushed.

Excessive wear on/in any of the following locations can lead to the symptom:
- new bushings, but worn foot change shaft (still sloppy fit - bushing must be large enough ID to accept "un-worn" portion of foot change shaft - but then worn portion of shaft matches up with bushings and is still "loose")
- wear of the ball end of the shifter arm/wear of the slot in the ratchet it matches with
- wear of the shaft/bore where the sliding pin fits in the shifter arm
- wear of the faces of the sliding pin or wear of the matching faces of the control shaft spool
- wear of the shaft/bore of the pivot hole of the shifter arm

Most of us haven't fully worn out a shifter cover/shifter mechanism by wearing out all, or even most, of those locations . . . but it can (and does) happen.

Ed

[hodakamax]

I'm with Ed. Some of these items don't show much wear, but the combination of worn parts all add up. It's usually all of the above.

Maxie

[MTrat]

On a side note. What, if any, advantage does the later 2-piece left side cover/shifting mechanism have over the earlier one piece style?

[vmxken]

I can vouch for the 'o' ring temporary fix. It worked a treat for me until I got a rebuilt shift mechanism/cover. I even had the correct 'o' ring 'in stock'....in other words I found one on the bench that looked like it may work and it did.