[4Nines]

I have the original carb for this bike that I am looking to rebuild and put back on. It currently has a newer Amal monobloc on it that doesn't look too bad, but I would rather run the original if I can. Neither carb has any sort of filter on them. Does anyone know what the original bike would have come with or what the most period correct and protective filter I screw onto the carb? All the pictures I can find online of original bikes don't really seem to show any sort of filter assembly.

 

[Teazer]

They originally had a rubber connector (one on ebay now) connected to a frame mounted filter box. It's so long ago that I rode one that I can't remember what they looked like but I'm pretty sure they fitted beside the oil tank, but I could be wrong. I know my DB32GS just had a bellmouth/velocty stack on the GP carb. Funnily enough I also remember those really short stack type screw on inlets, or was that on the A10?


Good question.

 

[4Nines]

My original carb looks exactly like this less the bellmouth: AMAL Pre Monobloc Carb 276 004R 276EF 1c Ariel KG Std 1950 52 GWO Complete | eBay

I wouldn't mind running something similar to that, but I don't really want to ride it without some sort of filter as well. Would a wire mess screw on with some foam in it work?

 

[4Nines]

Hmmm this look pretty nice!

276 Gauze Intake Assembly Stove Enameled - The AMAL Carburetter Company

 

[goldy]

They are a great old bike...air filter was optional. The carb should be an Amal 376/84

Parts for 376/84 for B.S.A B33 (Export) 500 O.H.V. - The AMAL Carburetter Company - The AMAL Carburetter Company

 

[4Nines]

They are a great old bike...air filter was optional. The carb should be an Amal 376/84

Parts for 376/84 for B.S.A B33 (Export) 500 O.H.V. - The AMAL Carburetter Company - The AMAL Carburetter Company

I was wondering how to figure out which one I had! Although, the link above says that the year is 1957 to 1959. My bike is a 1950. Do you think it's still that same carb?

 

[goldy]

Yeah...not much changed on those old girls at least as far as outward appearance goes. I just finished up a long term B31 project for a friend of mine; he has a B33 also...fitted with that carb, works perfectly.

 

[4Nines]

That's great to hear! So I guess I should just order that Amal air intake from them direct? Does anyone have any experience ordering directly from Amal and having items shipped to the US?

 

[goldy]

Being from Canada, I can't vouch for US customs, but I've never had any trouble getting anything from England up here...if fact the stuff I get from across the pond usually gets here quicker! I think the little air intake would look nice on it, at least it'll keep the birds from getting sucked into it.

They could also be fitted with a proper filter:

Part # 65-9196 Filter
# 65-1237 Adapter
# 65-9198 Elbow

 

[4Nines]

Thanks for the info! I will pull the carbs apart tonight and see what all I need to order

 

[4Nines]

The primary clutch seal is leaking pretty bad and needs to be replaced. So I bought a gasket kit to fix a couple other leaks and decided to pull the primary clutch. Once I got into pulling the clutch I noticed that the sprocket on the crankshaft has a shock spring on it. I thought once I got the nut loose that the spring would have enough play in it that I could just pull the but off the end. This doesn't seem to be the case and the nut still feels like it had a ton of pressure on it and I'm worried that it will strip the end of the threads and shoot off if I go too much further.

So do I need some sort of tool or spring compressor to remove this nut correctly?

 

[goldy]

Clutch seal? Aren't there just felt washers in there? and most of these things have a master link in the primary so you don't need to take the front sprocket off.

Anyhow, if you're going to do it, here's what I do: Loop some stainless steel wire around a couple of the spring sections. Screw the nut back down, then twist the wire loops down to hold the central part of the spring under compression. That ought to release enough pressure from the nut to keep it from shooting off the crank and hitting you in the balls...works for me and my family jewels are still intact.

 

[4Nines]

There's a massive leak behind the primary clutch. I figured there was a seal behind there that held all the oil in the transmission that has dried up?

If I do indeed need to remove the clutch cover completely then your method sounds like it will work well

 

[goldy]

No, all felt...one small felt ring that goes in a little metal ring around the transmission mainshaft and a bigger one that goes behind the slider plate. There is a seal on the transmission...does it smell like gear oil?
You sure you weren't running too much oil in the primary case? Anyway, I'm sure you'll sort it out.
Of course, oil shouldn't be 'pouring' out of it, but keep in mind you are riding something akin to Alley-Oop's dinosaur.
Love these old machines!

 

[4Nines]

Thanks for the help! I've been tied up this week, but I hope to get some more work done on it this weekend. I had the primary case cover off and there was still a huge puddle the next day under the bike. I can only assume that it's the seal around the transmission main shaft.

So it's just felt rings eh? If this is the case then I do need to remove the primary case correct or are these rings replaceable by just removing the primary clutch?

 

[goldy]

Well, lets see now...If memory serves me correctly, I think you ought to be able to change the felt washers just by removing the clutch basket, but if it's the transmission seal that's leaking, you will have to remove the entire primary drive and inner cover.
These things have a tendency to 'wet sump' as well when sitting unused. This can result in additional leaks too.

 

[4Nines]

I will remove the clutch basket and take a look. I have a feeling it's the transmission seal, but I will investigate closer and keep you posted.

 

[4Nines]

Is there a good shop manual for the 1950 B33 models? I have the original Instruction Manual, but it only talks about minor repairs and adjustments. It would be nice to see an exploded view of the clutch, transmission, etc so that I know exactly what I need and how it comes apart.

I've looked on ebay, but couldn't find anything good for the late 40's or early 50's.

 

[goldy]

You should be able to find something on CD...IMO the parts manuals are better than the shop manuals in some cases. You could try giving British Cycle Supply a call, they ought to be able to fix you up.

 

[4Nines]

OK cool. I've been looking around, but haven't been able to find anything good just yet. I will give that shop a call.