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Originally Posted by Magnetoman
Originally Posted by Tridentman
If you are a relatively small customer of a relatively large foundry
But BSA wasn't a relatively small customer, and they owned the foundry. The JB Weld approach was their management choice.


Could say the same for Yamaha and their TZ motors too.
Loads of jap stuff was porous and needed sorting before use on the track.
Loads of hardley castings were porous as well so the yanks and the japs
chose the jb weld approach too eh?

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Discussion of the various types of hole/bore gages for motorcycle work seems to be material that you'll only read here. However, the relatively small number of responses and reactions to such material that I've posted in this thread in the past does make me wonder how much interest there actually is in reading this type of content on Britbike.

The digital photographs in that post were easy enough to take (once I washed the grease off my hands), but only after pulling instruments from the cabinet, laying them out in ways that made sense, putting them away again, and cleaning up the jpgs in Photoshop. Obviously, the time it then took to write the rest of the post to explain what the photographs show wasn't negligible. Not for the first time, this leaves me asking myself, are such posts worth my time and effort to write if there's no indication that more than a half-dozen people read them?

Returning to specific motorcycle topics, the first photograph shows a length of 1¼-diameter C544 being bored to eventually become the ~0.84" ID sleeve gear bush.

[Linked Image]

If the final wall thickness of this bush were going to be thinner than it actually will be I would have turned the OD first and then bored the ID. Anyway, since standard drill bits seldom create a perfectly straight holes 3½" long I drilled it with a series of four ever-larger bits until a boring bar would fit, use of which to machine the final bore ensured it would be accurately coaxial with the lathe.

As can be seen from the second photograph, I stopped when the bore was 0.8391".

[Linked Image]

The mainshaft has an OD of 0.8403" so this leaves 0.0012", plus whatever final clearance I decide on, for the Sunnen hone to remove.

With the bore finished I then, ahem, turned to the OD, as shown in the next photograph, having decided on a press fit of 0.0015" (the bush that I removed had a press fit of 0.0011"–0.0012").

[Linked Image]

As the next photograph shows, I was finished with the OD when it was the desired 1.0015".

[Linked Image]

With the bush finished, I carefully measured its ID at four locations in it, then pressed it into the sleeve gear as shown in the next photograph.

[Linked Image]

I then remeasured the ID and found the 0.0015" press fit had reduced the ID by 0.0006"–0.0008", leaving that much more for the Sunnen to remove.

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Acquire knowledge and impart it to the people.

How many persons constitute a people?


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MMan--- I find your posts interesting and informative.
I always look at your posts as a priority.
So--please carry on posting as you have done up until now.

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Originally Posted by Tridentman
please carry on posting as you have done up until now.
Thanks for writing that, but I have to discount it for present purposes since you're one of the meagre half-dozen I already counted as reading my posts.

The layshaft is held at one end by a brass bush in the main case, The present bush allowed more play than I decided I would now like it to have. Also, I plan to use additional oil with the semi-fluid grease and want to eliminate (or, at least, reduce) leakage routes. So, I pressed the bush out.

[Linked Image]

I then made another one with a tighter slip fit to replace the previous one.

[Linked Image]

The reason it appears in the above photograph that the ID if the new bush is larger than the OD of the shaft is because I cut a short length of the inlet with a taper to make inserting the layshaft easier. Also, I used brass rather than bronze because the layshaft doesn't turn in this Burman gearbox so bronze isn't necessary. I then coated the surfaces with Yamabond 4 and pressed the bush into the case.

Turning to the other end of the layshaft, the next photograph shows that with it installed in the new bush, the face of the "washer" that is attached to the layshaft will be approximately flush against the surface of the outer case

[Linked Image]

Not shown is that I can slip a 0.005" feeler gauge between the "washer" and the flat so the layshaft has that much longitudinal room (plus the thickness of any gasket material) to move back and forth if it were unconstrained at both end.

The next photograph shows the sealing issue to be dealt with.

[Linked Image]

Both holes in the outer case lead to the world so both need to be sealed. Slathering the shaft and locating peg with plenty of gasket cement (probably Permatex PermaShield, because it is non-hardening, rather than Yamabond 4), along with the light press fit the shaft itself has with the outer case, might be enough to stop any oil leaks. However, to the extend the spinning gears generate any side thrust on the shaft, I have to assume the shaft could be pulled back and forth in operation by the ~0.005" end float, requiring the sealant to be flexible enough to accommodate that. I could reduce the end float by any amount I picked by dropping a suitable shim in the brass bush, but reducing it to zero doesn't seem like a good idea. Plus, even if there were no end float at room temperature, there would be when the cases warmed up.

I could machine an O-ring groove in the case for the shaft, but that still would leave the hole for the locating peg as a possible leak route. At the moment slathering the shaft and peg with flexible gasket sealant seems like the only reasonable solution, but I welcome suggestions.

p.s. there's enough room between the end of the locating peg and the outside of the case to press in a short length of Al as a plug, which is what I'll probably do.

Last edited by Magnetoman; 05/19/21 6:33 pm. Reason: p.s.
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Originally Posted by Magnetoman
Originally Posted by Tridentman
please carry on posting as you have done up until now.
Thanks for writing that, but I have to discount it for present purposes since you're one of the meagre half-dozen I already counted as reading my posts.
Treat it as a small group tutorial rather than an undergrad lecture smile

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Quote
the relatively small number of responses and reactions to such material that I've posted in this thread in the past does make me wonder how much interest there actually is in reading this type of content on Britbike.

Although there may not be many responses to the material posted, I feel certain that many more people are reading it and will ultimately make use of it.

Therefore keep posting, we all appreciate your hard work and efforts to document progress.

Last edited by gunner; 05/19/21 8:47 pm.

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Please DR. continue posting on this thread. It is not wasted!!!
John

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Originally Posted by John Healy
Please DR. continue posting on this thread. It is not wasted!!!
John

Good Doctor........that should be enough right there?

We are blessed to have you and folks like Mr Healy, Shane and Tridentman on here........we probably don't say it enough but THANK YOU!!!

Gordon Gray

Last edited by Gordon Gray; 05/20/21 12:47 am.

Gordon Gray in NC, USA.........as Lannis says “Gordon is either all in or all out.....there’s no in between”
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Think, A Canticle for Leibowitz.


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Originally Posted by John Healy
Please DR. continue posting on this thread. It is not wasted!!!
Originally Posted by gunner
I feel certain that many more people are reading it and will ultimately make use of it.
There's no way to be certain of that. The thread has over 1M hits, but since there's no way to know how many of those might be real, there's no way to know how many people actually read it.
Originally Posted by Shane in Oz
Treat it as a small group tutorial rather than an undergrad lecture
The last time I had to face an undergraduate in a classroom was at least 35 years ago. Since then, my teaching was to graduate students in an advanced specialty class. However, the lessons learned from lecturing to those graduate students apply to this thread.

Some years the students raised questions, instigated lively discussions, laughed at my lame jokes, etc. while other years the students sat in deathly silence. The instructor was the same, the jokes were the same, and the yellowed lecture notes were the same, so the only difference was year-to-year fluctuations in the specific students who happened to sign up for the class. The relevance to this thread is, years where I had an active, engaged class left me energized at the end of each lecture, while the other years I ended each class feeling like the life had been sucked out of me.

Effective lecturing (as opposed to filling time by talking at a group of blank expressions) is a two-way street. When done live I can immediately see in the faces of the audience whether an explanation I just gave was a good one, or if I need to rephrase it and try again. Obviously, I don't have the benefit of seeing a live audience on Britbike, but I don't even have the benefit of more than occasional feedback from a small number of people. Taking my recent post on bore/hole micrometers as an example, lack of any response or feedback makes it impossible to know if the time I spent trying to explain those instruments actually succeeded in explaining them, or if no one even cared about the topic so just skipped over that post.

Like "what is the meaning of life?", I don't have an answer to this so, like "the meaning of life," I guess I'll just have to hope the answer comes to me at some point.

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Hi MM and All
Maybe the so called lack of response to OT incidental items is down to a split of reader interests , one group who know exactly what you are
writing about and the second who are either afraid to question the lecturer or realise they will never afford or get so badly addicted to the tools you are describing???
I have to say the thread had gone way off topic for a while but glad to see You are back on track with the Ariel
The finish line is now firmly in sight so it would be a shame not to finish the write ups on the engine and gearbox

On the "tool war" front I have a Fowler Bowers digital readout kit of 3 point micrometers that uses interchangeable heads with a range from 3/16 to 5/8in. reading to 0.0001in. and also metric at the touch of a button
The feature of the spring loaded heads is that " Manual feel" is removed and taper/ ovality can be observed as the measuring head is passed through the likes of valve guides and such.
I keep it safely stored away and only bring it out to play when such fine measurements are needed

John

Last edited by chaterlea25; 05/19/21 11:55 pm.
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Originally Posted by Magnetoman
The last time I had to face an undergraduate in a classroom was at least 35 years ago. Since then, my teaching was to graduate students in an advanced specialty class. However, the lessons learned from lecturing to those graduate students apply to this thread.
There are a couple of advanced grad students here, but most of us are undergrads at best. By and large, any comments I make are likely to be distractions.

The approach of either a "Tools and Techniques" forum, or dedicated threads on the "Projects" forum may pay more dividends.

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Originally Posted by Gordon Gray
Originally Posted by John Healy
Please DR. continue posting on this thread. It is not wasted!!!
John

Good Doctor........that should be enough right there?

We are blessed to have you and folks like Mr Healy, Shane and Tridentman on here........we probably don't say it enough but THANK YOU!!!

Gordon Gray
Thanks for placing me in such illustrious company, but while they are firmly in the "dazzle them wth science" category I fear I fall into the alternative.

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Originally Posted by Shane in Oz
Originally Posted by Magnetoman
Originally Posted by Tridentman
please carry on posting as you have done up until now.
Thanks for writing that, but I have to discount it for present purposes since you're one of the meagre half-dozen I already counted as reading my posts.
Treat it as a small group tutorial rather than an undergrad lecture smile

Originally Posted by Magnetoman
Some years the students raised questions, instigated lively discussions, laughed at my lame jokes, etc. while other years the students sat in deathly silence. .... The relevance to this thread is, years where I had an active, engaged class left me energized at the end of each lecture, while the other years I ended each class feeling like the life had been sucked out of me.....

OK, time to start calling BS, in the nicest possible way of course. What MM needs is a good internet brawl to get him back on track.

I'll start it off by gleefully asserting that IMO, it would be absolute madness to NOT o-ring that lay gear spindle. I'm expecting to see a lip seal conversion on that final drive gear as well. It's what I'd be doing.

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Quote
I'll start it off by gleefully asserting that IMO, it would be absolute madness to NOT o-ring that lay gear spindle. I'm expecting to see a lip seal conversion on that final drive gear as well. It's what I'd be doing.

I agree, it would make sense to add seals wherever possible top stop the grease leaking out.

I guess MM's issue is that he is acting as a conservator as well as restorer so is probably reluctant to remove metal on cases/shafts.

If an O ring or seal could be added to the bronze bushings then that might work.


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Originally Posted by Magnetoman
p.s. there's enough room between the end of the locating peg and the outside of the case to press in a short length of Al as a plug, which is what I'll probably do.
Just to add to Stuart's stirring, is there room to machine .030" or so off the end of the layshaft (probably to a depth of 3/16" or so) and fit a blanking cup in the case? That's a similar sealing approach to the closed needle roller bearings BSA used in the A65 gearboxes and shouldn't make much difference to the shaft support.

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Whats not clear to me is whether the bush is blind or straight through, if its the latter then could it be made blind thereby stopping any leaks? Alternately fitting a closed needle roller as Shane suggests might be a good idea.

I'm surprised there are any leaks between the bush and case, usually bushes are a tight fit and don't leak at all, maybe the bush hole in the case is distorted?

If you need to seal the bush in the case I would use something like Loctite 641 which is intended bonding of cylindrical fitting parts but allows disassembly, they claim it prevents loosening and leakage due to shock and vibration, see This Link


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Living all my life in a NYC apartment I have no knowledge of or experience working with a lathe, etc. so I have nothing to add,
except that this thread is the one I normally check first.
The only other thread I’d prefer to read is the long dormant one dealing with the restoration of a Spitfire Scrambler

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Originally Posted by Stuart Kirk
I'll start it off by gleefully asserting that IMO, it would be absolute madness to NOT o-ring that lay gear spindle.
Originally Posted by Shane in Oz
, is there room to machine .030" or so off the end of the layshaft (probably to a depth of 3/16" or so) and fit a blanking cup in the case?
Originally Posted by gunner
Whats not clear to me is whether the bush is blind or straight through, ... Alternately fitting a closed needle roller as Shane suggests might be a good idea.
As a reminder, there are two ends to the layshaft. One end already has been dealt with by a new closed-end, top hat brass bush that was a press fit in the main case, along with Yamabond 4, and in which the layshaft is a sliding fit. Consider that end now to be leak tight, until proven otherwise.

The other end of the layshaft, which we're discussing now, might have been a press fit early in its life but it is now a loose fit in a through hole in the outer case (0.6264" OD shaft; 0.6320" ID hole), with a separate 0.15" through hole for the pin that keeps the layshaft from rotating. The layshaft does not rotate so a needle bearing wouldn't be appropriate, although shortening the shaft and using a plug, like also is used on some pre-unit BSA gearboxes, would be a possibility.

I don't remember there having been a problem with leakage from the two through holes, but they are adjacent to the kickstarter cover from which much grease oozed after finding its way there from the unsealed bearing so it would have been easy not to notice. However, now that I plan to put more oil in the mixture, I need to address all potential paths as best as I can even though some previously might not have been a problem. It well could be that simply slathering on a non-drying sealant like Permatex Permashield might be all that is needed, but I can't argue with Stuart's suggestion of machining an O-ring groove in the case. That, plus a short Al plug in the end of the hole for the locating pin, would make both holes leak tight, until proven otherwise.

Originally Posted by Stuart Kirk
I'm expecting to see a lip seal conversion on that final drive gear as well. It's what I'd be doing.
I'm afraid a lip seal isn't in the forecast, for reasons seen in the following composite.

[Linked Image]

There are three potential escape routes to worry about: 1) between the main shaft and the bush on the inside of the sleeve gear, 2) between the outside of the sleeve gear and the inner race of the bearing, and 3) through the seals on the bearing.

1) Any oil that made it via this route would end up in the clutch, so I'll have to deal with that possibility separately.

2) Although it appears oil could escape via the splines, they don't extend all the way through the bearing and the face of the sleeve gear that is pulled up tight against the inner race will seal any oil that tried to escape via that path. If I wanted to get OCD about this path, the face of the sprocket also is pulled up tight against the inner race so I could put sealant on the splines, although at the expense of making it more difficult to remove the sprocket in the future. I don't plan to do this.

3) If oil makes its way through the seals on the bearing, and if I polished the extension on the sprocket, installing a lip seal on the case would stop any such oil from escaping. Unfortunately, as can be seen, there is no way to install a lip seal on the gearbox housing, leaving the seals on the bearing as the only thing standing between cleanliness and oilmageddon.

I'll return to the layshaft soon, but turning to a different matter for the moment, it might require looking at all the following photographs in this post to see the extent of damage the outer case suffered in its earlier life.

The next photograph shows that the stud that holds the outer stamped-metal cover in place was repaired at some previous point in its life, and that the nearby back edge of the outer case (at the bottom of the photograph) also was damaged, possibly at the same time.

[Linked Image]

The metal surrounding the stud serves as the stop for the kick starter at both ends of its travel so that may be a clue to how it got damaged.

It's most easily seen near the top of the above photograph that there is a ledge just inside the outer surface of the case against which, as the next photograph shows, the circumference of the stamped metal cover sits.

[Linked Image]

The next photograph shows that the metal surrounding the stud, against which the stamped metal cover is clamped, sits ~0.032" below the ledge, so the cover will be somewhat distorted when it's clamped down

[Linked Image]

Adding a ~0.025" shim would reduce the distortion while still clamping the cover against the ledge enough to keep it in contact despite vibration.

The final photograph again shows how the metal cover sits on the ledge, and better reveals the amount of metal missing from the outer case.

[Linked Image]

So, reconstructive surgery will be needed if the gearbox is to be returned to as-newish condition. This will involve TIG to add the missing Al, followed by files to profile the outer surface, rotary table in the mill to form the ledge in the new Al, and possibly a die grinder to remove any excess Al on the inside area of the case that the mill might have left behind.

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"...the only thing standing between cleanliness and oilmageddon."

Lol!


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If it’s any consolation, your posts cause me angst. Fumbling through life with 2 point bore gauges and no bench micrometer in sight. Only a worn thumbnail for a roughness tester... you get the picture.

I also vote for an oring if you can come to terms with removing metal. Instead of an aluminum plug, does a grub screw make any sort of sense? You could limit the end play if that matters at all?

As for the kickstart stop.... I would make a note of that so when installing the kickstart lever so it doesn’t hammer against the stop....so the lever bottoms out before it makes contact. Similar to the lesser marque....helps keep the cover in one piece. Assuming your K/S shaft has splines and allows you to do that.

AML.... you know they make apartment sized lathes. Watch a few of these.

https://www.youtube.com/channel/UC9UjDtkpr2I-5G51vMJZvnA

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Originally Posted by Cyborg
If it’s any consolation, your posts cause me angst. Fumbling through life with 2 point bore gauges ...
Knowing I'm causing distress for at least one person gives me schadenfreude, so I appreciate you sharing your angst. For your viewing discomfort, the next photograph shows the smallest of my 3-point hole gages measuring the diameter of the hole for the layshaft locating pin to be exactly 0.150".

[Linked Image]

Originally Posted by Cyborg
I would make a note of that so when installing the kickstart lever so it doesn’t hammer against the stop....so the lever bottoms out before it makes contact.
Since it didn't happen on my watch it's only a guess that the kick starter hitting against the stop caused the problem. As the photograph shows, the lever has to travel past the bottom in order for it to hit the stop and the only way that could happen is if someone started the bike by standing beside/behind it rather than when sitting on it.

[Linked Image]

At the other end of its travel the lever is approximately 180° from that in the photograph, i.e. leaning rearward by ~10°. Perhaps an inopportune backfire rammed it into the stop? In any case, the kick starter simply rotates on a plain shaft so there's no way to adjust the stops at either end of the travel short of machining the gear quadrant.

Originally Posted by Cyborg
I also vote for an oring if you can come to terms with removing metal.
It turns out that McMaster-Carr offers O-rings that are "Softer than standard Buna-N O-rings for a better seal in low-pressure applications," and a package of those in the necessary ⅝" ID is on order for delivery tomorrow. That package has the one I need plus enough others to allow me to rebuild 74 additional Burman Q-type gearboxes. I ordered the thinnest available, 1/16", for the machining to be minimally intrusive on the case. They're -016 in the standard numbering scheme used for O-rings in case anyone else is rebuilding a Burman Q-gearbox and wants to make the same modification.

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Unfortunately they don’t make seal twisters for bores that small, but you need a kit anyway.

As for the schadenfreude.... congratulations on achieving step one. Now we’re getting somewhere.

Last edited by Cyborg; 05/20/21 6:00 pm.
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Originally Posted by Magnetoman
Originally Posted by Stuart Kirk
I'm expecting to see a lip seal conversion on that final drive gear as well. It's what I'd be doing.
I'm afraid a lip seal isn't in the forecast, for reasons seen in the following composite.

[Linked Image]

There are three potential escape routes to worry about: 1) between the main shaft and the bush on the inside of the sleeve gear, 2) between the outside of the sleeve gear and the inner race of the bearing, and 3) through the seals on the bearing.
Very nice. Thanks for the much more explicit photos.

About that leak path #3, I think I see the problem. Could a 67-3067 BSA Gold Star type lip seal be modified to go under the circlip? It is made to be installed exactly that way.

If not, A seal holder could be made with a flange to fit behind that clip. Then you could use any appropriately dimensioned seal you liked.

And gooping the splines with RTV is standard remediation on leak path #2. I've been doing that routinely for years. Disassembly has not been a problem.

Leak path #1 seems to have been ignored entirely by many British motorcycle makers. I'm inclined to ignore it too but then, I haven't made my way that high up the OCD curve yet.

1 member likes this: Magnetoman
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