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Messages - AWJDThumper

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1
Singles / Re: The running technicality's of the 276 carburettor.
« on: 11 July, 2023, 18:16:34 »
If the pilot passageways are clear then the problem may well be air leaking past the sides of the throttle slide. If in good condition, the slide should be a snug fit within the carb body without any obvious side play. Unfortunately, carbs wear and, although you can replace the throttle slide, you can't do much about the carb body other than to replace it.

2
Singles / Re: External thread cutting - stainless steel
« on: 25 May, 2023, 15:57:30 »
SS is a pig to machine at the best of times and one of the problems is that it work hardens not only blunting cutting tools but also making it hard to break off the chips produced. Best to avoid machining it if possible. I try to steer well clear of it on my lathe!

3
Singles / Re: B25 Primary chain is tight
« on: 22 May, 2023, 08:14:53 »
Have you checked the chain pitch with a digital vernier?

4
The Star and Garter / Re: Choosing a classic bike
« on: 19 June, 2022, 13:07:31 »
Most do - I subscribe to at least 6 different M/C forums!

5
Singles / Re: Clutch oil seal and sleeve gear bush
« on: 23 July, 2020, 14:54:36 »
Sorry to correct you, but what you feel on the outside is a cap that seals the hole in which the layshaft bush fits - you can't feel the bush itself. In principle, it could leak oil but this is only likely if someone has inadvertently disturbed the cap at some point - for example, while trying to get the old bush out.

6
Twins / Re: Conical Hubs A65
« on: 23 July, 2020, 06:52:39 »
I've never had a need to lacquer any of the conical hubs I've got as the polished surfaces have stood the test of time. However, I did lacquer the polished engine covers on my more modern Japanese multi and that finish has lasted well. Unfortunately, I can't remember what lacquer I used but I don't think it was anything that special.

7
Singles / Re: c15 paint
« on: 22 July, 2020, 17:55:01 »
For most purposes, it's best and easiest to get the frame and non-tinware powder coated. I've recently had to spray paint the frame and other bits of a bike I am restoring because my powder coater was not available but it was a lot of hard work in preparation and the finish achieved was nowhere near as durable.

8
Twins / Re: A10 amal 376 carb
« on: 22 July, 2020, 16:48:42 »
It's a bit of a crude way of raising the level of petrol in the float bowl in order to enrich the mixture. Modern carbs use a more sophisticated enricher device to achieve the same end but both approaches can end up flooding the engine and making it difficult to start.

9
Twins / Re: Conical Hubs A65
« on: 22 July, 2020, 07:13:11 »
I think the polished finish on conical hubs behave in the same way as the engine covers - it's probably the same aluminium alloy. Rather than painting the hubs, you can always lacquer them if you're worried about the polished surface tarnishing.

10
Singles / Re: B40 wheel building problems
« on: 22 July, 2020, 07:08:11 »
the local mx shop is doing the rebuild for him, we have known them for years and they know the offsets, the problem apparently is the nipples fall through the rim, previously the spokes were the wrong diameter. I had asked on a previous thread about spoke size.
this is the second rim and second lot of spokes He has bought and had to return, hence my asking.
previous rebuilds have been done in Bristol but both my old contacts have since passed on.
Getting hold of rims and spokes for a B40 should normally be a very straightforward affair especially if you go to Devon Rim Co or Central Wheel Components. I've rebuilt dozens of wheels and never had a problem. However, it's best to buy both rims and spokes from the same source because, even if the spoke sizes are correct, I think the nipple sizes can vary.

11
Twins / Re: BSA A10 keeps running rich
« on: 21 July, 2020, 19:51:03 »
Thank you ADJW thumper for your reply.

I have renewed the valve needle and valve needle seat.
Sorry i didn’t mention this.

Just checked again with the transparent floatbowl cover and this works as it supposed to work.

I have tried the following jetting.

Standard setting
MJ 240 - NJ 106 - PJ 25 - cutout 3.5 - needle 3 from top
Sparkplugs black, doesn’t pull fluidly

Smaller setting
MJ 220 - NJ 105 - PJ 25 - cutout 3.5 - needle 2 from top
Sparkplugs black, holds in

Bigger setting
MJ 250 - NJ 107 - PJ 25 - cutout 3.5 - needle 2 from top
Sparkplugs black, to much fuel to handle

Kind regards,

Piston Jockey
When trying to sort out a carb, it's best to vary only one setting at the time. Also, you have to be careful when interpreting plug colour because if you go out for a ride and come back and let it tickover, the plug colour can end up being a function of the pilot circuit only. To determine the plug colour for the bigger throttle openings, you need to run it for some distance at that throttle and then stop the engine quickly. It would be good to determine the differnce in the plug colour for at least a couple of throttle openings.

12
Singles / Re: B40 wheel building problems
« on: 21 July, 2020, 18:16:31 »
It appears to be a B40 rear hub and the rim also looks correct. Does he know what the wheels offsets are to enable him to rebuild the wheels?

13
Twins / Re: Conical Hubs A65
« on: 21 July, 2020, 15:21:50 »
Hello,
My front hub is a bit shabby, it has the grey painted finish.
Can you take off the paint and polish the hub ( inc air intake ) or is re painting the way to go.
Steven
They polish up really well - BSA only painted them to save on the cost!

14
Twins / Re: BSA A10 keeps running rich
« on: 21 July, 2020, 15:20:35 »
It sounds as though you have a fairing standard set up for the carb -presumably using needle position 3? Have you tried to reduce the main jet to see what effect this has? Although you have checked the float level, have you checked the condition of the float needle and valve to make sure this is working ok and isn't causing the carb to flood?

15
Singles / Re: Spark plug cap... good vs bad ?
« on: 20 July, 2020, 15:32:07 »
dont forget, the resistors also stop interference on tv's , more of a problem than radios in cars. this was the problem back in the sixties watching tv, you could tell when bikes or cars without the resisitors went past
TV interference was a problem in years gone by but is no longer an issue with the switch from analogue to digital transmission. Also, from a mitigation point of view, there are so few classic bikes on the road that any interference caused would be fleeting and not worth worrying about.

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