MK II choke jet size

Persohn

Persohn

Joined
Apr 26, 2019
Messages
23
Country flag
Does anyone know the stock choke jet size on an Amal MK 2 please?
I don't see any literature on this, even on Burlen website...
 
My search is for the right jet size so I don't get too high rpm just started, like 1800 rpm as it is now.:confused::eek:
 
Persohn said:
My search is for the right jet size so I don't get too high rpm just started, like 1800 rpm as it is now.:confused::eek:
Click to expand...
First I assume that when warm and choke (fuel enrichment lever) closed, the revs are a more normal tickover?

If so, is 1800rpm after starting really a problem? I assume you do not ride away with the choke still in use?

I am always conscious of not letting my motor run too slowly with cold oil, the camshaft does not get good lubrication below 2 to 2500rpm.

Warm your engine at least blipping above 2500rpm, then close the choke!

If you now have a normal tickover, still remember to blip the throttle occasionally to lubricate the cam.
 
I discover the MK2, and I am surprised by such a high idle under choke. The idle is at 1000 rpm with the engine warm.
When I take the bike, I usually start it when I am fully equipped, and I leave immediately by warming it up while driving, and I wait for it to be warm to exceed 3000 rpm.
 
Persohn said:
My search is for the right jet size so I don't get too high rpm just started, like 1800 rpm as it is now.:confused::eek:
Click to expand...

However, the choke jet delivers fuel.

If RPM is too high then in my opinion you would need to restrict the choke/enrichment air intake.
 
All carbs with this type of cold start enrichment device will rev too high, & revs need to be controlled by varying the lever, thus reducing the amount the plunger is out. Sadly both Amal MK2 & Mikuni VM choke levers don't allow for this, being either on or off. The best way around this is to convert to cable operation. Changing the jet won't solve the problem.
 
IMHO, you need to turn the choke off within 30 seconds of starting and you need to set the fully warmed idle a little higher - 1100-1200. If you start and ride off immediately, turn the choke off immediately after moving. It takes very little time to foul the plugs with the MKII or Mikuni choke on - it is dumping a lot of extra gas in the throat of the carb and since you're idling high, that extra gas is getting extra air somewhere so you may have a leak or a worn out slide.
 
You must log in or register to reply here.
Back
Top