B/M gearbox gears: 66-3212 vs 66-3215

[mikeb]

I’m attempting to refurb the B’s gearbox. It’s the old ‘round hole’ type about 1949.

By p/n, 66-3215 is the layshaft 2nd gear. 66-3212 is the mainshaft 3rd gear. Both are 25T, 9 dogs and measure identical with the same inner bush. See pic. Currently, the gear on the mainshaft has 3 drilled oil holes for lubrication whereas the layshaft gear has not. But:

this thread: http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1452064&cmd=show Says the layshaft gear (66-3215) should have the oil holes, so implies they are mixed up.
BUT! PES show 66-3212 (mainshaft - https://pesltd.uk/?product=66-3212) as having the oil holes and 66-3215 (layshaft) does not – the opposite.
Other online pics show random version of the truth. I also note there’s no oil hole on the layshaft first but there is on the sleeve gear. I’m looking for patterns – like reading tea-leaves.

Does anyone know exactly which is which? Or what is generally correct? And does it matter? I assume they’re way too hard to drill additonal oil holes. I was wondering about swapping their places anyway to change where the main force is on their teeth. (I’m replacing the bushes.)

All thoughts appreciated, Thanks

Mike

[limeyrob]

Vale Onslow (I believe its the son?) is listing both a 66-3212 and a 66-3215 new old stock on e-bay with photos.  Since Vale Onslow are in Birmingham and will have had these in stock and labeled right from the 1950's I would say the provenance is good and they are likely to be labeled correctly. Why not e-mail (ask seller a question) and ask which ones if any have oil holes?  The bushes look different.
https://www.ebay.co.uk/str/valeonslowmotorcycles
Search under the part numbers.

[mikeb]

thanks for the suggestion Rob. their ebay pics pretty clearly show 66-3212 (mainshaft) has having the oil holes and 66-3215 as not. ie same as PES, who should know their stuff. so that's the way its pointing.
Odd that all the BSA parts lists don't tell you and their diagrams overlook that detail tho have room to show it.
I might post a queston on Britbike and see if I get any bites - this being a bit out of lane for the A7A10 forum.

and - re the bushes looking different - in my pic the gear without oil holes has the bush removed.

EDIT: this pic https://britcycle.com/Products/66/66_3215.htm of 66-3215 shows no oil hole and a pic of the old packaging with p/n on it - so that adds wieght to 66-3215 = no holes.

EDIT2: and this shows 66-3212 with holes: https://www.brammotoren.nl/a-55725436/bsa-versnelling-bak-koppeling/bsa-66-3212-mainshaft-gear-25-tanden/ (other pages show 66-3215 without)

EDIT3: its only ebay but shows NOS packaging (with old written edit) - https://www.ebay.com/itm/394131878744 - 66-3215 = no holes

cheers

Mike

[limeyrob]

I would stick with the Vale Onslow info. You only need one good source, you don't want to get into a polling type decision where 3/5 say oil hole 2/5 don't, since some of the sources will be wrong.  More info does not equal a better decision once you have the right answer.

[mikeb]

Rob - i once spent 6 months in south asia where I learned that polling was a reasonable way to get directions when that was the only info available (no GPS back then). Agree that some votes are more reputable than others, so will defer to Vale-Onslow and PES.

Hence... 66-3212 (mainshaft gear) = oil holes
(unless someone like Julian S comes along and tells me otherwise!)

[mikeb]

Postscript: Some more of the mystery above revealed, which may help some fellow suffers with old B’s or WM’s.
Turns out there are various versions of the same layshaft – pn 66-3132 - or maybe other pns that at least look and measure the same - but differ. Some have a through drilling under the second gear into a centre oilway – mine does not (no drilling nor oil-way). All versions have a scroll to pull oil under that bush/gear.

Hence when some folk say the gear with oil holes should go on the layshaft they may be talking about a shaft with a through-drilling. Maybe that’s the setup on some WM20s – I don’t know.

Does it matter? Probably not. I put the gear with the drilled holes (66-3212) on the mainshaft and the ‘hole-less’ gear (66-3215) back on the hole-less layshaft, figuring if it has lasted 70+ years it should go a bit further. I’ll let you know how it goes in another 70 years.

[limeyrob]

I would blame the MOD. They had a habit of requiring lots of minor changes for their orders. Its was intended to improve reliability in hard service, but I suspect it was also a job creation scheme for the boffins.  It got so bad they created the COTS program - "Cheap Off The Shelf" to try and rein it in.