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1

Singles / Lucas E3LM - Advanced or retard question

« on: 19 October, 2021, 15:38:58 »

Hi,

See attachment.

Lucas E3LM magneto off a BSA M33 1955. Magneto rotation is clockwise. Amal Concentric 928 19cc idle, 106 Middle notch and 220 main jet - all advised by Amal for this bike. 20% general jet size when using concentric is their rule of thumb. In general no choke is required.

When slack cable - is this in an advanced position or a retarded position?

When I pull the cable via the lever and it tightens the cable am I advancing or retarding?

I am starting with Level pulled 50% of the way round. It starts first kick.

After warm it still runs faster with cable pulled - is this fully retarded meaning my mixture is too weak?

Thanks
Hamish

2

Singles / BSA M33 500 1955 Engine looses Power after 20 min

« on: 17 September, 2021, 19:37:59 »

Hi,

Bike has had a new engine rebuild, magneto rebuild, fitted with Amal concentric with 260 main jet (middle position needle) 19cc Idle jet 1 1/4 turned back. Oil getting to top of engine and back down on return pipe. Running Mineral SAE40 oil. Sits between advanced and retard even warm, doesnt like to advanced or too retarded. Carb has 10mm of heat protection with heat insulting plate... mildly warm to the touch after 20 min, not in any shape or form hot. Choke is fully open from the start and doesnt need any at all.

After 20 minutes of riding - getting up to 50mph, it slowly and surely starts to lose power to the point I have the throttle wide open it chugs along... sounds more throaty. Still idles well, but when hot gets slow, loss of power. When cooled it back to normal and will run quickly.

Any advice gratefully recieved.

Hamish

3

Singles / Amal concentric carb - BSA M33 + Aspen

« on: 07 September, 2021, 18:41:30 »

Hi,

Just a quick note that I took the plunge and fitted a MK1 Premier Amal concentric carb 28MM with a 19cc idle jet, 260 main jet, with the needle value middle slot. Seems to work really well and idles really well. Overall runs very nice and kind of fits in.

I am running this on ASPEN 4 stroke petrol and I have to say its so much less smelly and seems to go very well.

Keen to hear other peoples thoughts and experiences.

Hamish

4

Singles / Lights on / Lights off.... the lights keep dying then recovering.

« on: 07 September, 2021, 18:36:14 »

BSA M33 Plunger - 1955 - New Lucas Wiring Loom - diagram followed religiously, new battery 6v positive earth, refurbed, Lucas Magdyno, new solid state rectifier.

Lights switch off / off from the battery, all good.
Run the bike, get it night are warm running for about 20 min, all good... except the lights have died....
Leave the bike for 30 min or more to cool down... lights come back on.

Its a standard off the shop floor 6v positive earthed system, the magdyno was professionally rebuilt... I am so confused... any ideas?

Any ideas warmly welcomed!
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5

Pre War / Lights on, Lights off, Electrical conundrum!

« on: 07 September, 2021, 18:33:22 »

BSA M33 Plunger - 1955 - New Lucas Wiring Loom - diagram followed religiously, new battery 6v positive earth, refurbed, Lucas Magdyno, new solid state rectifier.

Lights switch off / off from the battery, all good.
Run the bike, get it night are warm running for about 20 min, all good... except the lights have died....
Leave the bike for 30 min or more to cool down... lights come back on.

Its a standard off the shop floor 6v positive earthed system, the magdyno was professionally rebuilt... I am so confused... any ideas?

Any ideas warmly welcomed!

6

Singles / BSA M33 Rear Stays - Length and height?

« on: 25 April, 2021, 20:57:51 »

Hi,

My bike is now up and running... sounds awesome, and is looking great. One issue I do have is the rear stays. The offside rear stay is a creative Burmese fixer and is wrong.

1. What is the length from bracket to mudguard, rear, and what height to the top of the mudguard (in the middle)

2. Does anyone have any spares? I am not buying the India stuff as 100% it will be wrong. I bought a chain guard and rear mudguard and they were a mile off!

Many thanks
Hamish

7

Singles / BSA M33 Plunger - Engine Numbers?

« on: 13 April, 2021, 17:10:34 »

The bike frame is 20 S 5341 which is a 1955 BSA M33 Plunger and the engine is a M33 OHV engine, but at some point its clearly had engine work. Perhaps a new engine or perhaps a new case... who knows.

C20 2 2102 5

The Middle 2 is much bigger than the rest and the 5 is about 1/2inch to the right of the 2102.

Any ideas around those numbers?

Hamish

8

Singles / BSA M33 Plunger - Final Drive Chain length

« on: 13 April, 2021, 16:55:52 »

Guys,

Nearing completion of my 1955 BSA M33 Plunger bike and its getting fired up this weekend. Will post video...anyway, the final thing to do is the final drive chain.

Kidderminster BSA have supplied a new chain, Japanese which looks very tidy, but its too long and will be shortened.

Its a 5/8th inch x 1/4 inch. Gearbox sprocket is 19T and the rear wheel drum is 42T.

Clearly this is somewhat subjective as you need to balance the gearbox primary drive and the rear final drive, but approximately how links will be in the final drive chain?

Many thanks and kind regards
Hamish

9

Singles / BSA Front forks - 67-5566 - I am so confused

« on: 18 January, 2021, 12:58:34 »

I am so confused... I needed to get a new front spindle for my 1955 BSA M33 Plunger... ex Burma bike...

The old spindle had been shaved down so it just slotted through. (probably hammered in and out regularly!

I checked the thread on the fork leg and it looks okay... I then ordered a new stainless steel spindle but it noted Left hand thread.

I popped the _rear_ QD hub spindle through the front to determine / double check it would not fit...right hand thread... but it fits in the front right hand threaded... screws in nice and tight...

Any ideas or suggestions please

thanks Hamish

10

Singles / BSA Single Frame Thread Clearing

« on: 10 June, 2020, 23:18:31 »

Hi Guys,

Quick Q. Following the power coating of my BSA M33 Frame I need to thread clear my frame in a couple of places.

There are a couple of threaded lugs on the Saddle down to gearbox...I think the battery and the rear mudguard will connect to them. Does anyone who what tap / thread I should buy?

Ta
Hamish

11

Singles / BSA Gearbox rebuild Plunger M Model - STD gearbox

« on: 08 June, 2020, 15:42:34 »

Gents,

I need some assistance. Gearbox BSA M33 1955 plunger -

1. Oil Seal - Sprocket side - Do I press the oil seal in from the outside and into the case - seems easy to do, or is it a nightmare fat hands pressing in from the inside out?

2. Replacing the main bearings - How on earth do I get them back in, any hints or tips

Hamish

12

Singles / BSA M Inner Gearbox - Wear around speedo drive

« on: 01 June, 2020, 13:18:43 »

Hi Guys,

I am sure this a common thread as it seems to be a common problem. The inner case of my BSA M Plunger gearbox is worn around the kickstart quadrant and speedo drive area... Its grinding metal. I have managed to get a new inner case for the gearbox part which is in amazing condition but I am worried about it getting damaged.

Does anyone know what is causing this e.g. which part or parts are worn that are causing this internal damage and how I fix it.

Many thanks for all your help.
P.S. I managed to get plunger columns from Baxter cycles in the USA... last pair and the bike is coming together nicely.

13

Singles / BSA Plunger Column...there are none world wide.

« on: 10 April, 2020, 10:37:43 »

Hi,

Having now trawled the entire planet from USA, Australia, the UK etc I have come to one conclusion... there are no plunger columns

67-4134 or 89-4041

When I spoke to the shops they all said the same thing... its not worth our while. This leaves a small problem for anyone working on the Plunger Frame models where the rear units are missing.

What is even more worrying is the fact that to get anyone to make these up is even harder because none of the shops want to take on the burden.

Any ideas?

If anyone has a spare column floating around I would be most grateful as this will stop my rebuild process and I am keen to get another BSA out on the road!

14

Singles / BSA Plunger columns etc

« on: 06 April, 2020, 17:41:09 »

Hi,

I had some very creative columns in the BSA when I dismantled it. I am now needing new / old columns and sleeves.

Does anyone know where they can be sourced. Draganfly don't have any.

Thanks
Hamish

15

Singles / BSA BM33 Nuts and Bolts List?

« on: 06 April, 2020, 17:39:27 »

Hi,

RE: 1955 BSA BM33 Plunger - Does anyone have a list of all the nuts and bolts needed for this rebuild. I have all the schematics but am looking to speed up the process.

Many thanks
Hamish

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