Amal Mk 2 questions.

Hey guys,
# 1. Can anyone give me the Outside Diameter of an Amal Mk 2 manifold please. 40mm ?
Also a photo of the manifold would be greatly appreciated.
# 2. Can anyone tell me if there is enough material to machine a taper on the flat side, in order to give a splayed effect,
as they do with Mikuni manifolds.
Amal manifolds are parallel, aren't they.?
# 3. Are 30mm and 32mm Mk 2 bodies the same.?, that is, can I machine 30mm bodies out to 32mm with no ill effects ?
# 4. Are the manifolds thick enough to machine out to 32mm.

Re question # 1. If they are 39/40mm O.D. then a F/M-F/M Mikuni push on adaptor will fit them and my Miks.
Re question # 2. If there is enough meat, then i will attempt to fit Miks to Amal, which will shorten up the distance
to the Carbs, giving more room to fit filters, I would really like to keep the original Air filter backing plate in place.
Re question #3. I have a good pair of 30mm Mk 2 Amals.

I do realise that I'm probably not the first to think of this, (Miks on Amals) and probably not the first to be shot down in flames.
It's just a thought from someone with limited cash flow, who likes to play around, and I have a good lathe man.
Then again, we all know what Thought thought.
Any help greatly appreciated.
AC.
If all else fails, I sleeve the Mk 1s, buy new Mk 1s, or contact JS.

Easy way to fit spigot mount carbs to a Norton, would be to machine up some spigots to take mounting rubbers of the carbs you want to fit, then cut off the flange type mounts from OE manifold, and weld the new spigots on in the right place.

I think manifold criteria is identical to head side of carb .

Id made a set of 14 in manifolds to tuneing spec ., actually just short of 14 in, which placed chokes at frame gusset. so they wernt fitted.BIG Trouble .
A set of insulators at head mightve done it, but mayve raised carbs . Was a brazers error , bronze rings to pipe bend tubes to 1/8 steel head plates .

I think I used a pair of similar zero length tubes to stock intake manifolds , but maybe just short steel ones, will try and find a picture .

If your heads dia. 30 PORTS , 30 mm I.D. steel ' pipe bends ' , welded to ' home made ' say 1/8 steel ' flanges ' , with lathed rings fitted for carbs
isnt difficult. Just some machine tools required .

Being in Aus , Id rip down the wreckers . EFI Falcon XF on or VL Commodore had big fancy bannana manifolds . as do BMs and jap trash .
( Aussie stuffs probably better grade alloy for welding ) J.B . weld glue would work , but on an intake I wouldnt risk it permanantly . that or
Aryldite would do for a ' mock up ' / test set . Most boat outfits are aligned to welders , aslso C.A.C. was alloy foundrey in S.A.
Most alloy is easily weldable and hand workable , file , disc grinder etc . Doing a coustom set would be a ' challenge ' but not difficult .
Mk II amals have no float ticklers to richen , by raiseing fuel level . Starting can be ' trying ' to say the least , without choke levers fitted .
( bit like a S.U. , useing one only , its a few seconds or more before the others getting fuel and chimes in )

70 mpg cruiseing at the old ' ton ' isnt bad economy though .A bit of downdraft at the carbs , up to 20 Deg s probly quite permisable too .

Carbonfibre said:

Easy way to fit spigot mount carbs to a Norton, would be to machine up some spigots to take mounting rubbers of the carbs you want to fit, then cut off the flange type mounts from OE manifold, and weld the new spigots on in the right place.

Click to expand...

The problem with that approach is that the carbs get moved further back, the usual manifolds used on Mk2's are much more compact

I've never had a Mk2 Amal manifold, but even if you could machine the angle on the flange it would be nearly impossible to fit the outboard bolt. Maybe if you fit a stud and nut, but it still would be close.

I think a better cheap option would be to get a piece of flat steel plate and cut it to fit the head. Then you could cut a pair of bends out of some old exhaust headers from an Asian bike (32mm) to the correct angle and weld it up. You could use your rubber hose sleeves to mount the Mikunis. One of my 850's had a similar set up on it when I bought it years ago.

Nominal 40 mm. The ones on my engine measure 39.7 mm.

There is enough room to bore the 30 mm ones out to 32 mm. They used to be available in both 30 mm and 32 mm sizes. Same casting, just different machining.

Don't know about boring 30 mm to 32 mm. 34 mm can be bored to 36 mm. 36 mm bodies are larger than 34 mm, so boring has advantage of smaller bodies allowing carbs to still be parallel with standard manifolds.

This picture shows the manifolds. They are parallel, although the perspective in the picture makes them look a bit splayed.



Ken

Thanks all.
It looks doable, although the Amal manifolds, once splayed, may be too short to get enough distance between the Miks.
Hence the reason for the adaptor kits being longer.
Of course we shouldn't forget that there would be an ideal length, to suit the motor.
Thanks for the photo Ken...The manifolds are quite short aren't they.
The Amal Mk 2s look machineable. That's an option.
Ron, what you suggest is certainly a good option, but not sure my "engineering skills" are good enough.
Rich, Yes my hole idea is to keep it short, so I can leave the Filter backing plate in place. Hopefully.
Carbonfibre, I didn't know weather the manifolds were weldable, so if it can be done and kept short, then it's an idea with merit.
Mat, I'll go to the wreckers today and see what's there. For a few bucks I might get an idea weather it'll work.
I guess I'm not the only one here in this situation, ( semi retired, certainly not millionaire), so need to count pennies closely.
The rebuilt engine is as sweet as, just need to sort the carburation out once and for all, and I'm a happy chappy.
Thanks again.
SWAP MEET TOMORROW, who nows.?
AC.