original carbs ??? - help ID'ing

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joe czech

joe czech

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I have these carbs in the parts boxes that came with my 74 commando. i'm assuming they are original to the bike. I need to establish a baseline to determine a course of action - rebuild, replace, ??? so comments on what I have here. is it cost effective to rebuild these with updates - ticklers, floats, needles/jets, rebuild kits, etc, or bite the bullet and opt for new premeirs.

original carbs ??? - help ID'ing


original carbs ??? - help ID'ing


original carbs ??? - help ID'ing


original carbs ??? - help ID'ing


original carbs ??? - help ID'ing
 
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I can't really tell you what's best, new or recondition.
I can tell you those are original Norton Commando carbs.

I can also tell you I have brand new Premiers on a 74 and they have been flawless right out of the box.
Others may different stories.
 
I can't see your photos (yet?) but I would expect original 850 Mk2 carbs to be marked either 932/29 and /30 (early?), or 932/35 and /36 (late?) or 932/33 & /34 if Mk2A.
 
Well if you want to just get the bike running for a while then much cheaper to fix up the old carbs.
If you want a quite permanent solution for decades to come then order the Premiers.
 
Same carbs on my 850, but yours outwardly appear nicer. If the slides aren't sticky they should clean up nicely & do well with some 'stay up' floats.
I'm considering new carbs myself, but I'll get all the good from the Amals before doing the swap because they're still going.
 
The carbs in the pictures are 32mm 932 amals. I have the original 930's on my bike which are the earlier 30mm version that I had sleeved and replaced the needles and jets. When I look at your pictures, I see a phillips head screw in one of the bowls, That screw does not look original, and is probably oversized because those "pot metal" carb body castings could have their threads stripped out pretty easily, so you need to address how much attention your 932's need regarding both slide to body fit, how good all the threaded holes are, and whether you want to have them sleeved for longevity's sake before you decide whether to use them or not.

Back in the day, there wasn't a "premier carb" to upgrade to, so I had mine sleeved when I rebuilt them, and they still work very well. It's hard to say what you should do. I don't even know what the new premier carbs cost versus having the old carbs rebuilt.

edited to add: maybe that screw is original, the angle and shadow make it look like it's not a cheese head screw, but maybe it is at second look... Still, you have to inspect all the threaded holes before you decide if the 932's are usable.
 
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Those are original fillister head screws...just some wear and tear. Not shelf item around my area. #8-32 I believe.
 
Those look the same, same numbering as my '74 850 MKII. Since keeping costs down was important for me as many things needed addressing when I acquired bike a year and half ago, rebuilding was the best path forward. New jets, needles, gaskets, fuel filters were done. Not more than $50 or $60 in those bits. New premiers run $350 USD a pair. You can also consider the Wassell Evolutions as these are made exactly like premiers, share same parts and run $240 a pair.
My bike has done 4000 miles on the original carb as single setup since rebuilding. Just finished putting the other one on for dual carb running and it seems good too.
If your slides and bores are not to bad, study up on the Bushmans guide for setup and pilot jet cleaning (extremely important) and get those old lumps working again.
 
jbruney said:
Those are original fillister head screws...just some wear and tear. Not shelf item around my area. #8-32 I believe.
Click to expand...

For some reason I can't see the photos but if they are the carb cap and float bowl screws then they are 2BA.

Edit: I see them now.
 
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The look like they have had a bit of a hard life.

I would get a gasket kit and new stay up floats and viton tipped float needles. Strip and use a carb soak cleaner and then an ultrasonic cleaner.on all the parts and reassemble. You will need to also clean the idle jet with guitar string or #78 drill bit.

Way cheaper to do all of that nd see how it goes than new carbs.

But, if your slides are worn and or your mating surfaces are at all warped, all bets are off.
 
It must be me but I think they look in really good condition
I'd clean out the pilot bush and try them
The slides/body have to be really worn out for them not to work
Maybe replace the needle jets while they are apart
 
For me they look like already recondition once, they have newer ticklers, so possibly they have viton tipped float needles as well.
In this case I'd check slides to body clearances and if OK I'd rebuild them with new gaskets, orings and needle jets.
Even more important is getting both float bowl and body surfaces straight and all the bolts in good shape and tight in their threads.
 
For what it's worth, I would fix up the old 932's because I'm good with amals, and a cheap bastard...
 
I also glassed my carb float bowls and mounting flange to ensure good sealing. 120 to 400 grit wetdry paper on a plate of glass with some wd40.
 
Damn good carbs until they give up the ghost, and those in the picture have much more to give I'll wager.
 
opened both carbs and i'm guessing the body bore and the throttle slide are the most critical part of the carb. here's a couple pics of the one body and slide. to me, from the little I know about it, but they look to be in fairly decent shape. cant feel any surface imperfections in either part, and the slides move freely. i'm thinking they are good for a rebuild. the mounting flange looks to be flat (used a machinist square). anything else I should be concerned about or looking at? BTW, I know nothing about the history of the carbs, that is, if they are original to the bike, or if they've been previously rebuilt, or ??? mileage on the bike is 16K miles.
original carbs ??? - help ID'ing


original carbs ??? - help ID'ing
 
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They do not show excessive wear in the body so buy Anodised slides to stop the potential wear now, they will then have the Premier upgrade for the body/slide, then you can decide if you want to upgrade the pilot so it's easy to clean or stay as is and use the #78 drill mounted in a WD40 tube for annual drilling out. That still leaves the stay up float and the aluminium float needle and any worn needle and needle jets but going by the body these may be ok for now and the rest can follow on once the bike is running.

The excessive wear comes from both body and slide being made from the same material which promotes galling.
 
joe czech said:
opened both carbs and i'm guessing the body bore and the throttle slide are the most critical part of the carb. here's a couple pics of the one body and slide. to me, from the little I know about it, but they look to be in fairly decent shape. cant feel any surface imperfections in either part, and the slides move freely. i'm thinking they are good for a rebuild. the mounting flange looks to be flat (used a machinist square). anything else I should be concerned about or looking at? BTW, I know nothing about the history of the carbs, that is, if they are original to the bike, or if they've been previously rebuilt, or ??? mileage on the bike is 16K miles.
original carbs ??? - help ID'ing


original carbs ??? - help ID'ing
Click to expand...

That looks like a chromed or sleeved slide?
Slide and carb appear to be in good condition.
 
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