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Int: +44 1564 783 192

How It Works & Part Names

The carburetter proportions and atomises the right amount of petrol with the air that is drawn in by the engine because of the correct proportions of jet sizes and the main choke bore. The float chamber maintains a constant level of fuel at the jets and cuts off supply when the engine stops.

The throttle control from the handlebar controls the volume of mixture and therefore the power, and at all positions of the throttle the mixture is automatically correct. The opening of the throttle brings first into action the mixture supply from the pilot jet system for idling, then as it progressively opens, via the pilot by-pass, the mixture is augmented from the main jet, the earlier stages of which action is controlled by the needle in the needle jet. The pilot jet system is supplied by the pilot jet (30) which is detachable on removal of the float chamber. On most 4 stroke models no pilot jet is fitted, but a pilot bush is inserted in the continuation of the pilot air adjusting screw passage. The main jet does not spray directly into the mixing chamber, but discharges through the needle jet into the primary air chamber, and goes from there as as a rich petrol-air mixture through the primary air choke into the main air choke.

The carburetters usually have a seperately-operated mixture control called an air valve, for use when starting from cold, and until the engine is warm; this control partially blocks the passage of air through the main choke.

1.Mixing Chamber
2. Air Valve Spring
3. Air Valve
4. Float Spindle
5. Float Needle
6. Needle Seating
7. Filter Gauze
8. Banjo
9. Banjo Bolt
10.. Cable Adjuster (Air)
11. Cable Adjuster (Throttle)
12. Cable Adjuster Locknuts
13. Carburetter Body
14. Throttle Valve Spring
15. Jet Needle Clip
16. Pilot By-pass
17. Pilot Outlet
18. Float Chamber Body
19. Float
20. Mixing Chamber Top Screws
21. Throttle Valve
22. Jet Needle
23. Choke Tube
24. Needle Jet
25. Tickler
26. Throttle Adjusting Screw
27. Float Chamber Washer
28. Jet Holder
29. Main Jet
30. * Pilot Jet
31. Pilot Jet Feed Passages
32. Feed Passage from Pilot Jet
33. Pilot Air Feed Passage
34. Primary Air Adjusting Screw



Opening times: Monday - Friday 9am - 6pm | Closed: Saturday and Sunday
Units 7 & 8, Rosemary Court, Oldwich Lane West, Chadwick End, Solihull, B93 0EY, UK

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