Author Topic: Geabox casing mismatch s/a  (Read 512 times)

Online muskrat

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Re: Geabox casing mismatch s/a
« Reply #15 on: 22.05. 2021 20:49 »
G'day Jules.
I agree with Swarfy as to the stop pin. Should be a straight pin, no top hat.
Also the bare spline should have a shrink on sleeve to stop the quad walking on the shaft. The repros are one piece (shaft & quad).
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline chaterlea25

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Re: Geabox casing mismatch s/a
« Reply #16 on: 23.05. 2021 00:11 »
Hi All,
It looks from the photos that the quadrant is not pressed fully onto the shaft?
It's also the other end of the quadrant  that meets the stop, the spring end is shown?
I don't know if that makes a difference?
I put up a post a long time ago showing a flanged stop pin as part of a repair process
for damaged cases, i have done quite a number of them and have not had an issue
Maybe whoever did this one made the flange a little thicker??

John
1961 Super Rocket
1963 RGS (ongoing)

Offline Jules

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Re: Geabox casing mismatch s/a
« Reply #17 on: 23.05. 2021 08:14 »
thanks for the feedback and focus on the kickshaft, I can understand why that is, having read your notes, so let me try and summarise:
* the first thing is, that all these bits were already assembled when I got the bike (engine was blown up, so no go, plus miriad other issues with the frame etc!), but the bike was "whole" and theoretically driveable "just" with a blown up engine, so presumably it went together ok before, so why not now???
* assuming it wasn't assembled properly before (somehow??) then I clearly have to change something to make this go together and it seems that the quadrant is out of position to start with. It looks to have been pressed onto the "spline", but not far enough? should the quadrant align with the bottom of the shaft or just press all the way up to the shoulder/stop on the shaft? Looking at Musky's pic, it seems that it shouldn't go all the way up and there should be a "spacer" (?) there, so how do I get this quadrant positioned correctly please?
* AND Musky, the quadrant looks like its awfully tight on the "spline" when its been pressed into position, I cant see how another spacer behind it sitting over the splines would really make any difference to its holding location, thoughts?
* now the shouldered stop, John's comment seems to suggest that the gearbox has been repaired at some stage and I believe thats the case, the bushes are clearly not original through the box, and seem to still be in reasonable condition. I think the shouldered stop is probably a good thing wrt its function too per John's past idea, so if I (can!) push the quadrant further on such that it aligns with the bottom of the spline, it will clear the shoulder, but will that misalign the pinion?? (I'm not in a position to fully assemble the box yet, so can't check that, what are your thoughts on this alignment please?)
* Finally, Swarfy's ideas about shaft location between the 2 steel bushes makes perfect sense, I have a top hat bush in the inner case and a plain sleeve in the outer, the outer sleeves for both the gearshift shaft and the kicker shaft are "almost" aligned to the bosses in the case maybe just a slight protrusion (to take the thrust away from the aluminium boss?), are they correctely located? If I (can!) move the quadrant on the shaft further up so that the quadrant and bottom of the spline align, then I suspect it will need end float adjustment/shimming....
Soooooooo, whats your thinking with all this please? thanks for your help as always....here's couple pics of the quadrant/shaft

Offline Swarfcut

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Re: Geabox casing mismatch s/a
« Reply #18 on: 23.05. 2021 09:18 »
 Jules. That last picture is worth 1000 words, the quadrant is the problem.  The face of the quadrant and end of the splines should be level to give the most area of contact against the top hat of the inner cover bush. You should then find the outer cover fits and with the gasket in place the kickstart shaft has a small amount of end float and turns easily. The collar on the stop pin is of no consequence providing it is clear of the quadrant and does not obstruct it. If the bush in the outer cover needs repositioning, heat up the cover before applying any force to the bush.

  Early gearboxes have a flat return spring. This engages on the exposed shaft splines, a relatively poor set up. Later design is for a conventional coil spring, hooked over the quadrant.  The spacer mentioned  (Part 67 3173 Spindle Sleeve) fits on the shaft over the splines and helps to support the coils of the spring.  This is shown in place in Musky's picture. Obviously not used with  the earlier flat spring variants. Later quadrants have this spacer incorporated into the design as a one piece unit, but  fortunately for the coil spring design  of box they are all mix'n match. Early quadrants can be used with late boxes as long as a matching tooth type pinion is used. You can see that in this case the exposed splines serve no purpose and are a leftover from the early  flat spring design, adapted with the use of the sleeve to suit a later application at minimum cost. Later variants  of quadrant are a brazed up one piece part.

  Moving the quadrant on the shaft splines should require a fair amount of force.  If it's a sliding fit that could also answer why it all fitted to start with.  A press would be handy, a big vice may do it. Don't go smacking the shaft, that's the hooligan's way.

 The mystery of how it all went together remains. Tell us what you find.

 In use, never let the kickstart pedal return with a bang. That is how the stop and its location suffer, comes loose and frets the mounting hole in the inner cover.

 Swarfy.

Offline Jules

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Re: Geabox casing mismatch s/a
« Reply #19 on: 24.05. 2021 00:53 »
thanks Swarfy, to confirm, I need to have the quadrant aligned "just" to the end of the splines, NOT pushed all the way up to the top of the splines and, I guess that "spacer" is needed to support the spring, I dont remember seeing that on teardown either, particularly as Musky mentioned its pressed into place too....
I still cannot understand how it was ever assembled before  *dunno* *cry*, cheers

Offline Swarfcut

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Re: Geabox casing mismatch s/a
« Reply #20 on: 24.05. 2021 07:17 »
 Jules. Just to the end of the splines is right. In practice such a feat of precision may be difficult to achieve, Quadrant much above the splines.... too big to fit, as now. Quadrant below....should fit fine, but only the splines bear against the top hat. Dead level, best of both worlds. Then of course consider any end float and sod all that and position the quadrant to give the best free rotation with no appreciable axial movement. It will all depend on what you actually have regarding manufacturing tolerances, wear, castings, bush thickness, gasket thickness etc.

  A similar situation can be seen with the position of the layshaft fixed pinion on the layshaft. Here the design uses a circlip to act as a stop when the pinion is pressed onto the layshaft.  Pinion ends up marginally proud of the splines and takes the thrust against the blind bush. So here, above the splines slightly, no float, should be fine if that's how it ends up.

 Out of interest, your quadrant has so called pointy teeth. For comparision Musky's shows what looks like the  flat topped version.

 Swarfy.

Offline Jules

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Re: Geabox casing mismatch s/a
« Reply #21 on: 24.05. 2021 08:13 »
Hi Swarfy, thanks for the follow through, appreciated....I did a thread on my quadrant and the new pinion that was sent to me from C&S(?)earlier and you guys did a great job then explaining pointy teeth vs flat teeth and also identified that the new pinion wasn't right either!! so from that I decided to reuse what I have which is still serviceable abeit not as good as I wanted for full rebuild.
Which leads nicely into what I have done today on the assy issue.....
I found the spacer that Musky identified in his pic, but its a sliding fit not press on Musky??
I managed to press the quadrant on until it bottomed on the spline shoulder Swarfy, which gave a perfect alignment to the bottom face of the shaft bearing  *smile*, it actually moved relatively easily, which surprised me.
The quadrant still contacted the flange on the quadrant stop though because the stop flange was 3mm while the flange on the top hat bush was only 2.5mm. The flange on the stop I m/c 'ed down to 2mm and all clear, aaaaaaannnnnnnnnndddddddddd the casings fit together  *smile*, just the bearings and endfloat to sort now, thanks all  *beer*
PS I still have absolutely no idea how it could possibly have gone together before!! but then my memory is not as good as it used to be and I did tear this down years ago lol  *conf*

Offline Jules

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Re: Geabox casing mismatch s/a
« Reply #22 on: 26.05. 2021 13:24 »
PS just to close out this thread and info. for others who have to get another case like I did....I think this case must have been in the rejected pile and then used up later in life, because apart from the joint face mismatch I also found the gear selector shaft fouled on an internal boss! The boss that the selector shaft fork straddles had a greater draft angle on it such that at the bottom closest to the case outer, the fork fouled as the shaft rotated...anyway, here's some pics to close out, I'm hoping that the sealing surfaces will be sufficient to seal up on final assy. you can see the reduced seal from the texta line...thanks for your guidance on all this too  *good3*