hello all does anyone have a good b31 or b33 rigid frame for sale ?

Hi Monty...You'll need to decide which version you want. Early B31 frames used the B1 gearbox which has narrower mounting lugs and is of a generally lighter construction than later ones. Consequently the gearbox mounting plates are closer together than on later versions and later gearboxes will not fit. The steering head cups and cones are also smaller on early types..they use the same size cups and cones as the Bantam. Many other parts are also particular to early models.
Later rigid frames share the same steering head dimensions as M Series and A Series models of all years.
If you want the frame as the basis for a project I would suggest you go for the later type..they are much easier to find parts for and the M type gearbox (B2 gearbox) is a lot stronger as well as giving you more options with regard to which clutch you use.
Early types are 1945-7. Later types 47 on until the rigid frame option was discontinued. I think that was around late 53 early 54 but would have to check the dates....Ian

Thanks Ian I had no idea that the parts were different on the early models .Going on the information you have given me I think I will go for the later version. Where can I get a good rigid frame does anyone have one for sale ?
Monty

I have such a frame. Any interest. I am from Denmark!

email (option): jens.jessen@mail.dk

Then you can build something like this fitted with M20 girders!

You can take an M20 and do this.

You can take an M20 and do this...

email (option): noam10@gmail.com

Where can I get one of those high level exhausts? I've got a B31 Project that would benefit from something like that.
Is it that offered by Armours? (HDB9H)
Cheers
Pete

email (option): petercomley@web.de

Here! http://www.ebay.com.au/itm/390525489590?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

How does one highlite stuff from ebay to save piss farting around?

Ta!

email (option): petercomley@web.de

Just use the number with the advert. click and hold curser move over number until it's blue then copy and paste. The exhaust was sold by BSA 111,unforunatly he sells the silencer on it's own but not the exhaust pipe.

"The exhaust was sold by BSA 111,unforunatly he sells the silencer on it's own but not the exhaust pipe"

bugger

email (option): petercomley@web.de

I did buy one from Feked very well finished but it was to large in diameter to fit the exhaust port, also their advert states fits from 1948-1960 swinging arm but all the bends are wrong for a ridged. Armours list one though. Try contacting BSA 111 and see if he will sell the exhaust on it's own.

Wow! I just bought a ZM frame to suit a sidecar set up. It would be great to put in a powerful motor to pull the side car. What type of motor is in this bike. What were the modifications?

Hi,

There is a guy who is looking to sell this bike.
He says that it stood for 17 years, “The motor is good, but the body needs work..”
I can spot something that appears to be a “Lambretta” carburetor,
The gearshift lever is missing, and other junk.
He is asking now for around 2850 UK Pounds,
He say that he has the title and all, but it looks too expensive.

Is that the small gearbox of the model? He did not specify the year, only “Overhead 500” (B33?)
Can this motor be fitted to a WM20 frame and gearbox?

Thanks,
Noam.

email (option): noam10@gmail.com

That's a lot of money for that, will cost a couple of grand to bring it up to scratch. Better off buying something decent to start with. It looks like it has Sunbeam front forks on it as it has an 8 inch headlight shell fitted.

Hi Ian, Thanks.

It does look bad, and was sitting for 17 years.
The price is high.
I can buy a BSA twin in mint condition plus spares for less..
what's interesting me, is if this motor can be used in an M20 frame,
and if the gearbox is of the old, weak type that Ian W. was mentioning..

Cheers,
Noam.

email (option): noam10@gmail.com

HI Noam...This engine will fit straight in to an M20 frame...This is what BSA did themselves to give sidecar users more power..The B33 engine + M20 frame made the M33 model..

You will need to change the oil tank fittings on the return side (of the M20) to include the feed for the B33s OHV rocker gear. You will also need an M33 head steady (easy to make)...an M33 exhaust system..a later petrol tank that had the bottom modified to make room for the rocker boxes (standard on the M33 and also used on later M20/M21 models) and the correct carb for the B33. The M20 magdynamo will fit straight on....

The B33 has 23 BHP as opposed to the M20s 13 and uses a lot less petrol!..My rigid B33 will do 75mpg easily...I have had my B33 about 35 years..It's another excellent BSA single engine with no weaknesses and they are very, very reliable..They also run a lot cooler than the sidevalves...

The gearbox in the bike you have shown is the standard one for the BSA Swinging arm range and is not the one I described in a previous post.
It is probably the best gearbox BSA made..unfortunately it won't fit into the rigid and plunger frames...Ian

A T piece in the return line will give you a feed to the rockers. You can use a B31-B33 petrol tank, but as the front mounting tabs are to low you need to weld on some metal on top of the tabs to make holes higher, I will be working in the garage tomorrow if you like I will photograph my spare tank to show what I had done to the tabs.

Thanks Ians, You helped me allot !

Yes, it would be great to see photos of the tank adjustment.

Now, I would need to see if I can wait for a while and get the seller
Some 1000 Pounds down. then it might be worth to either fix it,
Or to transform an M20 to a B33..

By the way, can you tell if it is a long or short rod B33?..

Thanks again,
Noam.

email (option): noam10@gmail.com

The rusty one in the picture is a short rod engine.

Thanks.

Yes..
I just talked with the guy, and he said that it is a 55' model,
And I found that BSA changed to the short version in 1952,
So it shoud be short.

I did not know one can tell from looking at the motor,
But I do not really know allot about it,
It is a new model that just came out..
14 years younger than my WM20..


Noam.

email (option): noam10@gmail.com

You can't really tell what is inside without stripping the engine, but the large fin barrelled ones are short rod from new, also BB engine numbers should be short rod.