I need to remove the cam followers and guides from the B21 engine.   Most of the later ones appear to have the guides screwed in and, most importantly, they have some flats on by which they may be tightened and loosened.

The B21's guides seem to be sub-terrain and smooth; no holes or flats to get a grip on.     

Any ideas on how they are held in and how they are removed?

I've recently had the need to remove the cams from my B21 single which should both be the same part number.

What I've found is that the inlet cam is numbered "65-2438"  and the exhaust cam number is of a very different form, specifically "A2-1".

The inlet cam is definitely the wrong part number for the bike (from a Gold Star I believe) but my question is is the "A2-1" number a later BSA equivalent number or is it an aftermarket part number?     Is there a conversion chart / table that shows the equivalents?

Any advice gratefully received!

A rather confused Alan

The threads on the crankcase studs that hold the pushrod tunnel and the oil filter gauze/sump plate in position are quite badly worn on my little B21 and I'd like to replace them if possible.

Simple question; do they just unscrew from the crankcase with the aid of suitably applied torque using for example a pair of Molegrips or is there more to it?   

Thanks

Alan

After my tail of woe regarding the piston and ring failure on my little B21 (See the Pre-war thread if interested) I want (no, need) to flush out the crankcase to make sure no debris remains - I DO NOT WANT TO BREAK THE BOTTOM END DOWN AT THIS POINT (which ultimately would be the ideal thing to do I suppose but it's not happening at the moment!).   

So, to aid me in this task I have a couple of questions if I may?

1) Can the oil pump be removed and put back easily from the engine with it in the frame and, perhaps more importantly, what points do I need to look out for e.g. shaft, gear or whatever alignment, gaskets, bolts to remove or not remove etc etc?

2) I think (if my understanding of the Parts Book is correct) that in my engine the timing shaft/wheels/cams etc have a retaining/bearing plate underneath the outside case so can I just remove the timing side outside crankcase cover to clean/make sure no debris is lurking there whilst leaving the valve timing etc intact?

With the oil pump removed for separate cleaning, my plan is to flush the crankcase through with paraffin or similar and dry/clean out with compressed air to ensure any debris is released and expelled.    Similarly, with the timing side cover removed that area will be similarly treated.

TIA

Alan

The old jokes are the best but in this case, the piston really is broke and it's no longer a joke

After covering two or three hundred miles on the little B21 the engine breathing became heavier and it became harder and harder to start when warm.   I also began to noticed a distinct lack of compression particularly when hot.   I checked the oil filters and found small pieces of debris and so, suspecting ring trouble (some of the debris looked decidedly ring like which was a bit of a clue), I removed the head and barrel.

It wasn't a pretty sight with all 3 rings in more pieces than you could shake a stick at but, perhaps more problematic, the land between the rings has been damaged and so clearly it's only use now is as a paperweight so I'll be needing a replacement which, might be tricky due to its age.   The bore escaped relatively unscathed but will need a re-bore just to be on the safe side and I'm just about to try and determine what size it currently is.

A  note from the parts book that it should have a 65-409 piston (and a quick Google for replacements didn't look particularly promising).  However there appears to be no number of that form on the piston but it does have the number 11563, "AE" and a patent number 616820 cast inside the skirt.   I think that might be a Hepolite number although that number appears to relate to a Triumph engine. 

So, my questions are:

1) Is it indeed a Hepolite piston?

2) Is it the equivalent of BSA's 65-409 or is it one that's been used as the correct one was previously unobtainable?

3) The piston has two slots, one either side of the gudgeon pin that separates the crown from skirt fore and aft - is this typical BSA or is it more typical of an alien piston?

4) What are the possible causes of the damage?  One suggestion is fuel wash which would marry up with the tendency for flooding as I believe the wrong carb is fitted which is bigger than it should be.  I had to drop the needle to the lowest slot to get the mixture somewhere closer to correct (although still on the rich side)?

5) And of course the big question, where might a source a suitable replacement?

TIA

Alan

The cylinder head on my B21 leaks somewhat and I've been reading up on the dismantling / reassembly process.   Apart from not being able to quite get my head around those weird head bolts, I'm unclear as to the need for a cylinder head gasket.    Looking at the parts list and the Haycraft instructions it appears that there isn't one (my interpretation of the statement "metal to metal" in Haycroft and the apparent lack of an entry in the parts list).   

Although still in one piece at the moment my engine definitely has a copper head gasket in place.   Might this have been desperation on the behalf of a previous owner to prevent leakage from a warped or damaged head joint I wonder?   If this is the case presumably I would need to get the head and possibly the top of the barrel skimmed?

Any informed thoughts and/or advice would be most welcome!

Alan

Hi  Everyone,

Some may have spotted I joined the forum a few weeks back and today I have received my BSAOC welcome pack so now I'm a fully paid up member from  the Herts and Beds border.

I've recently acquired a 1939 B21 De luxe which is essentially complete (minus a speedo, see my previous thread) but needs a bit of TLC before it chugs off up the road.    It came with a BSAOC dating certificate that a PO had got along with an age related registration certificate.   It claims to be an Empire Star (by the badge on the tank) and on a previous MoT certificate although from my (very!) limited understanding of BSA model numbering I've not found any official reference to the B21 ever having that title.   I understand that the B21 was made between '37 & '39 and there was the complimentary B22 series which did have the Empire Star name.  It appears that a crude categorisation between the two models might be; the B21 series had a hand-change gearbox and the B22 had a foot-change box although it's not as a simple as that of course. 

My bike seems to be a bit of a hybrid (albeit matching frame and engine) as it is a B21 with a hand-change box adapted for foot-change with an external positive stop mechanism!   This mechanism wasn't working when I got the bike but I've now disassembled, cleaned, lubricated and correctly assembled it  (well at least better than it was) and now all four gears can be selected although you'd be stretching it if you said it was slick!  The mechanism seems to contain all the bits that would normally be found in the box and they look identical to the illustrations in various manuals of the foot change versions (Ratchet plate, 2 pawls, 2 parallel springs etc) so it looks like it was an official mod or upgrade.

From what I've seen there didn't seem to be a 1939 version of the B22 just the B21 standard and B21 de-luxe, so is it that the de-luxe is in essence the B22 / Empire Star or is it more likely that a PO stretched a point and applied Empire Star markings to it just to make it sound a bit more imposing?

I note in the members handbook it says that there are handbooks for the B21 and B22 series in the library but they do not appear in the member's area on the website (It does say on the website that Pre-War are not available) does this just mean they've not yet been uploaded but they could be acquired in the interim by more direct means?

Anyway, I'm sure they'll be loads more questions on girder forks, BSA head bolts, BSA colour schemes and numerous other topics over the following months!

Any advice / guidance gratefully received.

Thanks

Alan

Hi, I'm very new to the forum and BSAs, having recently acquired a '39 B21.    I'm sure there will be many questions but to kick off;

It suddenly struck me after a good "look-at" that there is no speedo on the bike - I'd been hoping for a lovely Smiths Chronometric which I happen to think is an amazing instrument.   More importantly, I also noticed that there appears to be no speedo drive gearbox fitted to either wheel.

1) Is it likely that the bike did not have initially / has never had a speedo? (I don't know when it became a legal requirement to have a speedo)

2) Is there a cunning speedo drive output from the final stage of the gear box lurking somewhere?

3) If there is no provision for a speedo drive originally, is it possible to fit one and is it easy to do?

Otherwise I'll have to go down the route of crafting or purchasing an electonic replica.

Thanks in anticipation.

Alan