Archive for the ‘Carb – Amal’ Category

XS650: Amal Single Carb   Leave a comment

Melv from Greensand Foundry has produced single carb manifolds for an Amal. Nice simple carbs.

Carb exiting to the left …

I made this manifold because I had lots of requests from people asking for a cast 2 into 1 that will fit in a standard frame loop. I made this to fit an Amal MK1 concentric, but will be making these to fit other carbs in the future. The Amal carb has a rubber o ring that seals against the machined face of the manifold!!!!!

Straight mounted carb …

He states: This is the first time I started the bike in 4 months. It usually starts first kick but the battery was flat!!!!! This is my straight mounted 1-2 manifold made to fit a standard XS CV carb. Internal bore diameter is 33.0mm. I made this because a number of people wanted it … personally I don’t like the standard XS carbs so adapted it to fit a trusty old Amal MK1 930 Concentric. My range of XS parts is listed on UK ebay!!!!!.

The jetting/settings on the twin Amal 930’s is   Main jet #140   Needle jet#106   Throttle valve (or slide) #3 1/2   throttle needle is 2 indent (which is the 2 small engraved lines above the clip grooves) and the clip position is second groove down or midway.

For the straight mounted 1-2 everything is the same apart from the main jet which is a #170.

See his other stuff here and here.

Amal site.

Notes On Rebuilding the Amal Mark 1 Concentric Carburetter.

This old tractor. Amal info.

Hitchcocks Amal.


Posted February 1, 2012 by xscafe in Carb - Amal

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XS650: The Greensand Foundry   Leave a comment

the greensand logo


A while ago I picked some rather tasty finned covers up from The Greensand Foundry. Look good on the XS.

They’ve been busy lately. Alongside single carb manifolds they’ve extended their catalogue.


more on offer


iron cross generator cover


iron cross points … celtic pentagram generator cover


celtic pentagram generator cover


pentagram cover


pentagram generator and finned points


generator cover


13 generator cover


yamaha tuning forks


and for the points cover too


super sport points and finned clutch covers


super sport points covers


XS points and finned clutch/oil


XS points covers


email at:

fleabay at: hardtail28-2008

These are cast. In his small workshop. A one man band.




getting ready








backyard industry … literally … space is tight


single carb manifold


amal mounted


in frame … here with no air filter … am sure I have a pic with filter-cant find it


Contact details:

email at:

fleabay at: hardtail28-2008

  • click on: ‘Angebotene artikel’ or ‘Items for sale’ … found in the profile box where the seller can post his photo if desired.

XS650: Engine Temp. RHS   Leave a comment

A week or so ago CM wrote asking about operating temp differences left and right. Why does the rhs run hotter?


xsjohns, rip, engine temp recording…with cooler…left and right can run up to 30° or so difference


I’ve been out of town. Away from my computer. Exiled. Disconnected. But not deleted. Basically this is the answer I sent him.

Over the years I’ve heard many postulate. From aerodynamics to exhaust placement.

When you look at the engine design you see all the mechanical parts are focused to the right. As is oil flow.

Hot oil is sucked up through the pump. Slowed at the filter.

Mechanical action from the tacho, oil pump, primary and clutch all add frictional heat.

Aluminium is a good conductor. Heat gravitating upwards meets that from the combustion chamber and exhaust ports.

To the left we have the generator. In an air cell. Dry. Different thermal properties.

Allows the left to act more efficiently and effectively as a heat sink.

When Yamaha built the carbs they did so symmetrically. Jetting specs both the same. Each operating in different thermal environments. Built in imbalance. With appropriate feedback loops.

If you have adjustable needles it is possible to richen the right hand carb by raising the needle.


lowering the clip raises the needle…enrichening the mix


XSJohn, rip, ground needles with different tapers as a set. Left and Right. The canadian needles apparently are similar. Replace needle jets and jet needles together as a pair.


xsjohn, rip … on his needles … no grooves here, his production needles were grooved


John also built wings or foils to deflect airflow over the cylinders.


xsjohn’s wings…notice the deflector under the lower clamp


Others install oil coolers.


remote filter and cooler…so positioned the cooler will reduce air flow over the head


heidens side filter-cooler


Today there are many diagnostic techniques. Years ago I had an interesting conversation over too many beers with an Australian Naval NCO. Have never been fond of military types. Too rigid. Thinking actively suppressed. Later I was to learn the corporate world is, in theory, no different. In practise, a lot worse. Establishment meeting punk – the shock was mutual. He was a vibration analyst. Spent his time listening to machines sing. No different really to listening to your motor through a long solid screwdriver. He had a lot to say about the internal workings of Australia’s navy.

I would like to see a series of  Infra Red pictures of an XS650 motor running. Done in a resolution capable of  differentiating temp gradients within the 80-300° range. You would see some definite nodes on the right and fronts associated with temp assymmetry.

I come from the southern hemisphere. Live in the north. Apart from north and south there are other differences too. Here they drive on the wrong side. When you pull the bath plug, flush the toilet, water runs anticlockwise-the coriolis effect. I wonder what this does to other physical gradients Winking smile.

XS650: Pod Air Filters   3 comments

I lightened down my bike considerably. All the electrics went. Run batteryless. Removed the air-boxes. Left the whole section under the seat empty.

Looks cool. No good for the motor.

Had a pair of el-cheapo pods lying around. More or less the right diameter, according to the label. After fitting I decided I could do better:


now how are you supposed to get a good seal there…also see the cracking along the edges-this was new out of the bag


big inner lip…everything restricted…diaphragm vacuum port at the top: pilot air jet-lower left: main and mid range air jet-lower right: bowl vents in the middle


these filters had never been used


was then given, under protest, a set of these


larger surface area


no restricting step


may not hold up esp. with no support…wonder how long it will last…is the rubber ethanol proof?


  • very thin
  • where-ever you look the filter wants to break out of the rubber
  • see the large hole in the flange lip? WTF?
  • strong enough to hang unsupported?
  • ethanol proof?

Not an optimal solution. But heaps better. Will have a look around for a K n N to compare.

When I think about it I guess I should add here that pods generally increase engine breathing capacity. The immediate effect is to lean the carb mix. More air, less gas. Pistons and valves don’t like this. Get a little intimate with your carbs. Odds are you may have to massage your jetting.

Reading will tell you. Chop those plugs.