carb-nage

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soturi

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...carnage? get it?

sry.

so the float bowl is clearly done:
carb-nage


but is this slider also dead?
carb-nage


that's after an overnight soak in chem-dip. it's multi-colored because the chem-dip took whatever that finish is off of any worn surface. whish i'd have known that was going to happen before i did it. same story on all the carb bits...

also this corrosion wouldn't come off:
carb-nage


and i have no idea who was chewing on this:
carb-nage


but they were also kind enough to bore out one of the float bowl screw holes and replace it with some random screw they forced to fit:
carb-nage


so i think i know the answer, but i'm interested in the opinions of the experienced. are these carbs garbage now, or what?

here are bore measurements on the right carb (from deepest to shallowest, left number is in-line with the top cover screw holes, right number is the measurement 90-deg from that line); all in mm:

34.96 | 34.84
34.94 | 34.84
34.94 | 34.89
34.94 | 34.88

matt
 
You need to talk to Jerry about some new Amal Premieres.
Best money you can spend on an old Norton.

Glen
 
Try soaking the bowl in a jar of E10 gas for a week and see if the crud softens up.
Does the slide look thin where it is worn ? How does it move in the body ? If it is stuck or sticky, you can fit them, but it is slow going. Shine it up with some simichrome. If the slide is loose have the body bored and a stainless or brass sleeve fit to the side
Put the body in an ultrasonic cleaner with a little CLR and see what happens. You will probably have to drill out the back side of the body in line with the pilot jet to clean it. Size your drilling so you can tap a 10-32 thread in the hole. Use a short screw with an o-ring to plug the hole. The chew marks are superficial.
Make sure the bowl top, bowl mounting surface, and the mounting faces are flat.
Put a 10-32 (IIRC) helicoil the the buggered threads.

If you decide to buy new carbs and the old ones are 30mm, throw them my way. I'll pay the shipping...

Greg
 
Slide is shot and likely its bore too but new anodized slides with less cut out may solve remaining air leak issue. The bowl and bottom body layered in zinc oxide from the 'pot metal' alloy and the chewing looks like over alkaline exposure erosion. Try a vinegar boil for 10 min next. Could use epoxy thread repair to help get screwed again. Might actually recover them for decent function.
 
I am in total agreement with Glen as to getting in touch with Jerry about some new carbs.Best money I have spent on this motorcycle.
Mike
 
There is a very slim chance that you may get these to run again. But if you do, they may never be quite right and will more than likely be a constant source of frustration.
By looks of you current progress, it would seem that you have plenty of time to source out a new set.
 
Triton Thrasher said:
I don't usually buy new to replace dirty items.

Slides look bad long before they cause any trouble.
Click to expand...

There is more than just dirt there ,you can see considerable wear on the slide. It looks a lot like some very well worn ones I replaced with Premieres awhile ago. The improvement in the bike was profound. I calculated that the savings in fuel alone paid for the complete new carbs in about two years, 12,000 miles per year.
If the slide is worn, it is likely that also the bore is worn and also needle and needle block. All of these issues can be dealt with, but at some expense. By the time carbs are resleeved and rejetted, the cost approaches new, but they still aren't the Carb that the new Premieres are.
By just cleaning them and reusing, it can be made to run, but it will never run as nicely as it will with the Premieres.
My opinion and experience of course.

Glen
 
One place you'll (almost) never get clear is the idle jet and associated passages. You can drill out the opposite side of the air screw adjustment carefully tap it to take a cut-off idle screw and at east get at the idle jet from both sides, but the slide is shot as is the carb bore, most likely; the float need seat, might be saved. But, when you get all that done you'll have a set of carbs that are mediocre at best.

A good learning exercise, no doubt, but time consuming and poor results are just about guaranteed. Get new carbs, or a Mikuni carb conversion kit, then go worry about something else, your Norton has no shortage of components that desire attention or adjustments that would like tweaking...RPC has experience and inventory with both solutions.

Bill.
 
Aw shoot we could all just buy CNW and be done with it but where's the skill satisfaction it that. I vote try to fix the carbs and see what happens - to calibrate the rest of us on what's possible by dedicated Commando lover. Only real down side I can think of is trying to start to many times so wears off lobe lifer finish.
 
I just got my carbs back from Lund Engineering..........he re-bores the body and makes a new sleeve for the slide. I'll have to wait for spring to try them out though .........


Tim_s
 
Chem Dip is pretty clear on the instructions: 30 minutes max.

Overnight? You see what happens when you don't read the instructions?
 
Keep them or lose them? That's a hard question. At first I thought of course, they are worth a shot. It's really not possible to gauge a slide's condition just from a photo as they tend to get score marks that look like yours pretty quickly but will still have a lot of life left. It's all in the fit and rattle factor. That's the first thing I'd check. If you can access a bead blaster, it would be a 30 sec shot per carb to clean the inside of the bowls and inside bottom of the carb bodies. And cleaning and freeing up/checking pilot passages is a well documented procedure. These carbs are basically about as simple as a toilet. However if you do need a lot of parts to bring them up to snuff, new may be the way to go. A lot of us initially, me included may have been looking at it from an experienced Amal users point of view and we tend to have a lot of spare Amal carbs and parts laying around making it a fairly economical endeavor to bring a couple of dead ones back to life. A couple of Premiers may be the way to go for you though... And your old carbs will then become your first start to your very own Amal carbs and parts collection. :lol:
 
Tim_S said:
I just got my carbs back from Lund Engineering..........he re-bores the body and makes a new sleeve for the slide. I'll have to wait for spring to try them out though .........


Tim_s
Click to expand...
Ha, funny story about Lund. A long, long time ago when I first had them done I was wrong about the procedure. I thought they bored and sleeved the body and needed a new slide to make the fit correct. So I sent the carb bodies off along with two brand new slides that of course they machined down just like any other slide and to accept the sleeve. But I'm still using those original carbs and they are still perfect.
 
Bore wear air leak can be compensated by inital questimate of how much less cut out to order then finer tune by some hand fliling slide lip which can actaully help low down response i found. Could also put em together with grease on slide to see if functions well to know the rest of the carb fixed up well enough to buy anodized slides. Do note i've been told grease is life risky to attempt but me and at least one other got away with it to get good diagnositc results for a couple hundred miles. Epoxy paint might seal bore surfaces for a few years.
 
Seems to be two camps here - buy new and fix what ya got, that are never going to agree.

I'm still running the original carbs on my '70 750. Starts first or second kick, idles at ~900 rpm, picks up cleanly, goes well enough to get me in trouble with the sheriff, returns ~50 mpg. I don't know what the rest of you are getting, but that kind of performance is good enough for me.

Needles and jets are wear items, plan on replacement every 10-20,000 miles.

I would think that the chances of buying a set of new carbs for a 40+ year old bike that are set up correctly out of the box are slim. Then what ? And next spring when the bike won't idle... Better to buy another new set I guess.

Greg
 
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