Sleeving Amals...not sure it's what it's cracked up to be (2011)

Re: Sleeving Amals...not sure it's what it's cracked up to b

daveh said:

Mike, I'm kinda with you on this. I re-sleeved a pair of Amals myself using seamless brass tube epoxied to the slides and bored the bodies to true cylinders. BUT, it was one hell of a job on my small lathe and I wouldn't do it again. I feel it just delaying the day when I have to scrap the carbs and buy new. Yes, the mod worked but for how long? A new set of bodies (no need to buy a complete carb if the rest is OK) and chromed brass slides is not mad money and that is what I would go for when these carbs wear out. One then has a set of carburettors that may be rather primitive but are easy to tune and maintain and you can retain a paper element air cleaner which I think is better than a K&N. I would like a set of Keihins that Jim Schmidt at JS Motorsport sells and I have no doubt they are superior, but I can't justify the cost right now.

Dave

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Jim sells $25 OKO carbs with the OKO branding removed for considerably more than $25! Keihin dont make 32mm PWK carbs, and this can be easily verified by anyone interested. To fit the OKO's to a Norton you need flange to spigot type adapters which are easily available, and I would think its possible to buy all thats required for less than half the cost of new Amals, which will wear out pretty quickly.

Re: Sleeving Amals...not sure it's what it's cracked up to b

Carbonfibre said:

Jim sells $25 OKO carbs with the OKO branding removed for considerably more than $25! Keihin dont make 32mm PWK carbs, and this can be easily verified by anyone interested. To fit the OKO's to a Norton you need flange to spigot type adapters which are easily available, and I would think its possible to buy all thats required for less than half the cost of new Amals, which will wear out pretty quickly.

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That's interesting. Must look into it some more.

Re: Sleeving Amals...not sure it's what it's cracked up to b

Product Name Hard Anodised Forged Alloy Slide - Number 3 - Cutaway 900 Series
Part Number 928/0603HA
Price $37.52

Description
Hard Anodised Forged Alloy Slide - Number 3 - Cutaway 900 Series

The latest upgrade for 900 Series Mark 1 Concentric carburetters from the Amal Carburetter Company are precision made forged aluminium throttle slides with a high quality hard anodised surface finish that offers superb resistance to wear and smoother throttle operation.

The slides are fully interchangeable with existing slides with the same range of cutaways available. The slide has been re-designed to improve rigidity and robustness while retaining the efficiency of the original.

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http://www.amalcarb.co.uk/ProductDetail.aspx?Id=37410

Re: Sleeving Amals...not sure it's what it's cracked up to b

Well, I might as well add my 2 cents worth. Instead of sleeving, I just purchased a set of new Amal 930's. I rem they were
$100 each. The price gives you the time frame. I was having backfire on decell and after reading all the posts all over the internet I figured I needed new carbs. Wrong. They made no difference. I learned over time it is primarily the slide opening at closed throttle that makes the difference. I have to agree with a lot of the other posts that there are numerous "myths" perpetuated on the net about all sorts of things related to our fine machines. These include carb sleeving, jet and needle wear, 300 amp alternators, funny head steadies, belt drives, rebuilds at 10k miles, electronic ignitions, advance curves, funny carbs, sprocket ratios, and brakes. On the other hand, I think it is great that certain owners derive so much satisfaction, and sometimes grief, in applying these upgrades to their machines. This is what guys do to their machines. It is a state of mind. It is what turns one on. It is a hobby for gods sake. That is why I take tremendous satisfaction from tuning in to this forum every day, usually from one to three times per day. I have to classify myself as a "mythbuster" because I am quite happy with my Norton just the way it came from the factory with all its purported shortcomings. I rode a new 70 Commando in Europe and from coast to coast in the USA. I have had three other Commandos over the years. I have never been stranded on my bikes or had to truck one home. From memory, my current 71 with some 35k miles on her runs just as well as the new one I had in 1970. The only reason she is a tad slower now is that she is carrying a bit more weight. Remember to go as quickly, it takes about 1 hp for every 7lbs of weight you add to your machine . This is no MYTH.

Re: Sleeving Amals...not sure it's what it's cracked up to b

And thay still have plenty of power.

Phil

Re: Sleeving Amals...not sure it's what it's cracked up to b

I'll have to agree, when you use the standard issue components, it all seems to work as advertised adjusted per spec. That's why I am always reticent to go to the Norvil belt drive for the primary, the IE, the headsteady, special drive chains, they all seem to bring many more issues into the bike that was never there to start with. I hear all these horror stories, but yet have to experience loose exhaust nuts, blown head gaskets, drive chains coming off, etc. It may be too that I don't thrash it to death. Who's to know. I do know every time I do an after market thing, it brings more headaches. I'm sticking with the original equipment (but I may try the Norvil belt and a new rotor and stator).

Dave
69S

Carbonfibre said:

Re: Sleeving Amals...not sure it's what it's cracked up to b

The VM Mikuni carb is what Amal looked at before making the Concentric, so these carbs are pretty dated, and while being of far higher quality than the pot metal Amal's, and likely to last far longer, they wont provide the type of performance gains to be had from a modern flat slide set up.

In the US it seems that the excellent Taiwanese OKO flat slide carbs are commonly being sold with OKO branding removed, for around double the normal selling price in other parts of the world! Anyone able to find a source of these carbs at the proper price, and a couple of flange to spigot type adapters, is going to have a very good set up for less than half the price of Amals, with no need to mess around with sleeving etc when they wear out!

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The OKO branding is removed, because the less expensive carbs are Chinese copies. See the link below to learn about the differences. See

http://www.mid-atlantictrials.com/Copies.html

Amal did not compensate for metal cooling distortions above 30 mm size bodies so rarely two carbs same ID's or squareness right out the box. In past chrome plate often flaked off so no one I know sells them for a long time. Anodized alu slides or brass works a treat. Best to leave slides loose as factory or even more if worn and get new slide(s) with less cut out. Use pilot jet to set baseline float level so best idle happens near 1.5 turns out.

I gave up on the o ring levering weak flanges tight enough to seal and not back off. I made fairly thick heat tolerate rubbery/composite flat gasket.

Amal carbs, Girling shocks, Dunlop K81 TT100 tires-all antique, outmoded and easily surpassed by modern equivalents. But back in the day, these are what builders of other performance machines of the age used because their stock components were crap.