Amal type 5/101 carb rebuild (BSAl29)

[robbsa]

Hi All

I'm rebuilding my carb which is an AMAL type 5/101. I believe they only made this one for 1 year, but its pretty similar to the surrounding years.

I have most of the parts and picked up a few extras from AMAL a few years ago.

One issue (if its an issue) is I can't seem to remove the jet block. obviously don't want to do anything forceful as the body is in relatively good condition.

1. do you think I need to remove it to recon the carb?
2. does anyone out there know how-  there seems to be an alignment feature of the part that the main jet screws into. does this plate at the bottom unscrew from the body? does the jet block slide out from the top?

any help would be appreciated.

its off a 1929 BSAL29 if you haven't seen my other posts.

thanks
Rob

[cardan]

1. do you think I need to remove it to recon the carb?
2. does anyone out there know how-  there seems to be an alignment feature of the part that the main jet screws into. does this plate at the bottom unscrew from the body? does the jet block slide out from the top?

Hi Rob,

1. Unless you are going to bore out the body, you probably don't need to remove the jet block. Make sure that all the little airways are open and clean.

2. All the ones I've seen are just pushed into the body, held in place by the large gland nut you have already removed. Without the nut they often just fall out. If you need to get it out, get a piece of soft wood/plastic that fits down the carb body from the top, and give it a gentle tap. If it's really stuck, boil the jug, pour the water over the body around the jet block, and try again.

Cheers

Leon

[33d6]

Cardan is pointing you in the right direction. At this stage all you need do is give it a thorough soak in a good solvent and then a a good session in an ultrasonic bath. This is to ensure all the wee passages are well clear. Poking with a bit of wire is not recommended. Worry about a thorough rebuild at a later stage when the bike is on the road. Get it mobile first then fuss with getting it spot on. A mobile bike you are steadily improving is far more pleasant to own than a never finished money pit.
Remember you have an L29. This was the bike a working man on a modest income bought. It did everything he wanted at a price he could afford. It was no Brough Superior. Keep that in mind and the beastie will give you good service.

Cheers,
 

 

[robbsa]

Thanks guys, great advice.

[Rex]

In my experience some jet blocks are more firmly "fixed" than others; some take a gentle tap with a hard wood dowel while others need gentle heat, but either way it must be done  as there's a little tiny bleed hole which seems to block itself just for fun.
You may be lucky with just solvents and compressed air but a wire brush strand will show that it really is clear.

[iansoady]

I agree with Rex, the one on my Sunbeam was very firmly stuck and needed quite a lot of heat to free it. I'm also far from convinced that careful use of wire will damage those fine passages. If you are a guitarist (or know one) then the cut off ends of the high E string are  .010" give or take.

[TGR90B]

Following removal of any protruding jets, undo the large capnut a couple of turns. Find a deep socket (or similar) about the same diameter as the slide. Slip this in the slide end and gently compress the whole lot in the vice. Once it moves you can unscrew the capnut a bit more and repeat the process until free. You can't effectively clear the pilot drillings without removing the jet block.

[Rex]

I'm also far from convinced that careful use of wire will damage those fine passages. If you are a guitarist (or know one) then the cut off ends of the high E string are  .010" give or take.

To me, it was sensible advice issued back in the day when riders would poke, prod and fiddle just for fun. Too frequent or too heavy-handed a poke through jets would undoubtedly enlarge them, but  a gentle push really isn't going to do any damage, especially as it probably won't need doing again for another fifty+ years..

[john.k]

You can get a set of oxy tip cleaners for a couple of bucks ......selection of wires from around 002  up to 040 ,or more.and designed for cleaning small orifices in brass and copper.

[murdo]

Nylon fishing line is also useful for clearing small passages.

[robbsa]

Thanks again for the tips.

I am also trying to track down a part number for the needle jet.

I spoke to amal down in salisbury and they provided me with a part (106) but it doesn't have the right fit to the carb body. the original has a thred to attach to the plate that sits on the underside of the body. I have a contact who may have a selction of spares but needs to know a part number if I can find one.

otherwise i'll be making a replacement.

[TGR90B]

I don't know where you are, but Google and speak to the bloke at Surrey Cycles. He's very Knowledgeable.