What size pilot jet should I use?
The pilot jet is sized correctly if the fuel screw setting falls between 2.5-3 turns out. The pilot jet is sized correctly if the air screw setting falls between 1-2 turns out, with 1.5 being the sweet spot.
How do you tune a concentric Amal?
Tuning:
- Adjust the Main Jet (Throttle at three-quarters to full open).
- Adjust the Pilot Jet. ( Throttle up to one-eighth open)
- Adjust Throttle Cutaway. ( Throttle one-eighth to one quarter open)
- Adjust Throttle Needle. ( Throttle one-quarter to three-quarters open)
- Readjust the Pilot jet.
What is a carb pilot jet?
The pilot jet handles the mixture from idle to 15 to 20 percent throttle. Air comes in through the front of the carburetor drawing fuel up through the pilot with a vacuum that is created as the air flows through the pilot circuit.
What happens if pilot jet is too big?
Typical Lean Conditions: (A too-large main jet also mimics this symptom.) – The engine runs hot, knocks, pings and overheats. – The engine surges or hunts when cruising at part-throttle. – Popping or spitting through the carb occurs when the throttle is opened.
Does pilot jet affect idle?
The idle circuit pulls through the pilot jet exclusively. The pilot jet typically can deliver no more than 15% of the overall fuel when the throttle is wide open.
How do I know what size main jet to buy?
Consult your manual first to find the stock size. Also pay attention to the numbers on the side of your old jets, which you’ll be able to see in the steps to come. A larger jet number means a bigger hole and more fuel. A smaller jet number has smaller holes and should be used if your engine needs to run leaner.
How do you know if a carb is Amal?
Q: How do i identify what carburettor i have? A: Most Amal carburettors are stamped up with a specification number before they leave the factory. For Pre-monobloc’s & Monobloc’s this will be stamped on the top of the flange. For MKI and MKII carburettors this will be located on the side of the carburettor body.
What happens when pilot jet is too small?
If the bike surges or hunts, the pilot jet is probably too small (lean). Other indications that the pilot circuit is lean are popping or spitting through the carburetor when the throttle is opened and popping or backfiring through the exhaust when the throttle is shut.
What does a bigger main jet do?
A larger jet number means a bigger hole and more fuel. A smaller jet number has smaller holes and should be used if your engine needs to run leaner. Whether your machine is running too lean or too rich is a good starting point for choosing your jets, but using a jet calculator minimizes trial and error later.
What does putting bigger jets in a carburetor do?
To increase fuel injection from a carburetor engine, you need to install bigger carburetor jets – not an entirely bigger carburetor, just the carburetor jets. Bigger carburetor jets allow more fuel to enter the carburetor from the fuel tank. Usually, installing bigger jets alone is enough.