I still can't get my B21 oil tight.     

The main culprits up the top seem to be the rocker feed banjos, the blanking plug in the hole for the non-existent de-compressor actuator and the top end of the push rod tube (circular with castellated nut type).

Nevertheless it's a lovely little bike to ride now I've fully re-built the engine and stopped it seizing up which, of necessity, has a slightly hybrid bottom end due to lack of a replacement late standard timing side crankcase casting.   I'm a mere beginner when it comes to BSAs but I do have a little bit of engineering nouse (45 years in the aerospace world taught me a couple of things) but previous owners ....... 

Alan

That looks tidy.     

The trouble I've found with my oil filter arrangement is:

1) As previously mentioned, you can hardly see what the oil level is with the filter in place and it's a very slow job topping it up!

2) It's all fine and dandy until you take the filter out when any detritus that has been caught has a tendency to drop out of the bottom filter and into the tank 

The moral of the story appears to be don't remove the filter unless you ar going to drain and flush the tank.

Alan

As a reference dimension; the overall diameter of the top cap flange = 43mm.

This is how the filter sits in the tank.  Note how little of the tank contents you can see and hence the non-standard, annoy the purists, but highly functional oil sight tube.

Photo #1 is what I found in the oil tank (along with a load of sludge, some old Wet & Dry paper .......   Previous Owners a?  )

I cleaned the perforated tube up and attached two brass rings to the ends to help stop the tube cutting through the felt.    My oil return pipe has a cup at the bottom that the filter sits in and the sprung loaded top cap seen in Photo #2.

Mrs Groupleader very kindly sewed up a new felt filter tube on  her sewing machine.  Photo #3.    The felt tube was wetted, past through the perforated tube and the ends of the felt were gradually persuaded to go back on themselves and then the assembly was left to dry thoroughly resulting in Photo #4.

You might be able to scale  the photograph.  Unfortunately I can't remove the filter to measure it until I do an oil change (as all the muck falls out of the bottom of the filter into the oil when you do so ..... )


Alan

This was the chap I was going to get to try and salvage my B21  Timing side case.    Some of his work is simply astonishing.

Usual caveats;  I don't know him, I've not been paid by him but I did speak to him a couple of times when I was trying to sort my problem out and I'm sure I would have been a satisfied customer if I hadn't found a replacement case which was the easier option!

"Badfoot Customs" is his (unusual) name.

badfootcustoms@gmail.com

07542 278116

This link features a relevant repair.

https://www.facebook.com/share/p/3J9qp1Mn6VBCwa3B/

Alan

Thanks Steve.       

We managed it in the end with a blade in the screw driver slot and some Molegrips.    I did need two pairs of hands; one pair to put the pre-load on the other pair to fiddle the selector shaft and layshaft bearings into position without disturbing the selectors.   After a couple of goes we managed to find all four gears and a neutral (although I suspect there maybe a few other neutrals lurking in there also - there were before  )

Alan

Funny enough I've just had to replace my kick starter return spring.   

I found it quite tricky getting the 1/2 turn of pre-load on re-assembly.  It needed a suitable tool for the screw driver slot and another pair of hands.    We managed to use a bit of plate and some Molegrips.  If I have to do it again I'll make a proper tool from bar material with a suitable "blade" on the end with a centering spigot and a hole for a Tommy Bar at the other end.

It seems to me that the design of the spring/quadrant gear is very poor; the coils get displaced as it rotates as the tang/end of the spring is only partially retained in/against the quadrant gear and the part of the spring that actually takes the load bears on a sharp corner on the gear.    The broken spring shows extensive wear on numerous coils.   I wonder were all that metal went?  Oh, I know, in the gear box.    Still it's a bit late to query the manufacturer I suppose!

Alan

I'm certainly no expert but have learnt a lot rebuilding my '39 deluxe model ......

The first photograph shows what it looked like originally with the static cam axles and the (very sensible) fixed outer support plate and the oil pump drive retaining nut with a shoulder that ran (I think, I can't really remember) in the bearing.   

Unfortunately you may recall that a PO had completely mullered the timing side casting and I was unable to find the required replacement so an earlier B21 standard case had to be substituted which has the live cam axles supported in the timing cover and no support plate.    The end of the crankshaft is not supported in the earlier standard engines and whirls around in the fresh air of the timing cover.   The older style cams are seen in the second photograph.     

The really Eagled Eye Expert observers will also note the later and incorrect mag idler gear still in use.   This is because the earlier, thinner, timed breather idlers seem to be rarer than the proverbial output from a rocking horse.      The replacement casting had to be modified to use the later idler stub axle thus dispensing with the timed breather (the original crankcase breather on the drive side is still there and in operation!) .   The older style timing cover shown in Photo #3 had to be modified to accommodate the thicker, later idler by machining off some of the projection on the inside of the cover.     It will be noted that there is no crankshaft bearing support in the cover between the two cam bearings.

I hope that is of interest if not use!

Alan

That's topical, I cut a new one out for my B21 only yesterday!

First time I've been in the (any) gearbox, necessitated by the one piece kick-start return spring becoming the two part version.

It's a game getting it all back in and working isn't it.    How does one correctly pre-load the spring and for that matter, check the end float of the main and lay-shafts?

Alan

That little BMS book is excellent if you can find a copy.

This link might also be of use ......

     https://bsa-info.nz/parts-lists/#Various

Alan

Wow!   What a superb bit of modelling!

Very nice indeed.

Alan

On my B21 the return is also on the outside and the rocker feed is from it ......

Here's a comparison of the two timing side castings with the potential replacement on the left and the original on the right.   Both have the same (basic) casting number and are marked OHV.     The main appealing features of the potential replacement are:

     1) The casting is intact, has good lugs and as far as I can see so far no cracks
     2) The bores of the cam followers are not parallel and the follower guides are as intended (thin-wall bronze(?) tubes for full diameter followers)
     3) Good, flat, non-scratched oil pump mating face

The main drawbacks of the replacement are as previously mentioned, the throat is slightly over size and the the head bolt holes are in the wrong positions.

One other discrepancy I have spotted is the timing wheel shafts each have two (bi-directional) helical oil grooves where as the originals have only one (unidirectional) helical oil groove.      Am I correct in thinking the bi-directional grooves would provide better oil distribution along the length of the shaft whereas a single groove will tend to force the oil to one end?   Is this likely to be a problem or an improvement?

The main drawbacks with the original casting are:

    1) Possibly holed case, re-instated with  very poor replacement lugs.   
    2) Numerous cracks between, for example, the main bearing oil way and the side of the casting
    3) Very poor oil pump mating face (would need re-machining flat and possible need for a spacer plate to replace the missing material)
    4) The register to prevent the main bearing rotating is missing and hence may well be the primary cause of the lack of oil/multiple seizures
    5) Great chunks of the casting missing (for example see around the inlet cam follower)
    6) Worn, non-standard cam follower guides and followers still stuck in casting - maybe the act of "forcing them in" caused a lump of the casting to break off?

Anyway, the replacement generally looks to be a lot better bet (at least to me at this point) providing the throat diameter can be reduced and, most importantly, the head bolt holes can be re-located in a manner that will be adequately strong enough to withstand the loads created in this most critical area.    Time will tell ...

Alan

Indeed.   I don't know what engine the replacement casting I have found is from, it is the correct casting number and the machining on it looks identical to the original with the two exceptions you have mentioned so some "significant" work required to make use of it.   But compared to the replacement B21 casting (that I haven't got ....) at least I'm in with a chance!

I also have a replacement drive side casting with the correct casting number but that is from a B23 which also has similar problems with the addition that, because it was a side valve engine, the tapping for the rocker oil return pipe has not been machined although that's a simple problem to solve in comparison.      However, at the moment, I'm trying to re-use the original drive side casting as it's major flaws are the "not very pretty" replacement lugs.   I can probably live with "not very pretty" lugs as long as they are mechanically OK and to do so would retain the engines identity (just shows you how silly the whole concept of "original engine based on the specific bit the number happened to be stamped on" is!

Alan

I'm with Chaz!

Quote from: chaz on 21 February, 2022, 20:52:56
Good job  its not life or death!!

The first time the doctor finally actually saw fit to see me he pronounced that he didn't understand my symptoms (I'd been going downhill for some months) and admitted me to hospital.   As I was going through the admissions procedure (in A&E) I collapsed with complete heart failure.  When I awoke I was told that I would be getting a Pacemaker the very next morning.

The only thing I think that is certain in this regard is that the quality and efficacy of the service that patients receive "from the health service" is, for whatever reason, entirely dependent on where they live, the NHS trust responsible and the specific individuals who deal with them.   There is certainly no "common standard" of care given or received (that's why some services are in "Special Measures" after all!)