The Tillotson Carb On The Rotax MAX
| 19 November 2013 |
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As previously reported, Vroom! Magazine recently tested a Tillotson carburetor on a Rotax MAX engine.
Vroom's testing showed this new carburetor, called HM-2A with 27mm venturi, was 3-tenths faster per lap than the stock Dell'Orto VHSB 34mm that comes with the FR125 MAX.
- Please note, this carburetor is NOT LEGAL for use in AKA Rotax or TaG racing! Also, we know of no current plans to introduce it to either. We reference this article for the purpose of general interest. It is only suitable for racing where rules permit use of an alternative carburetor.
Above: Both sides of the Tillotson HM-2A designed for use on Rotax MAX
pic - Tillotson Racing
Above: The Tillotson takes up far less space than the Dell'Orto
pic - Tillotson Racing
Above: HM-2A fits directly into exisiting mount
pic - Tillotson Racing
Above: High (left) and low (right) speed adjustable on-the-run jetting
pic - Tillotson Racing
Want to read and see more? There is a PDF of the article published in Vroom which can be downloaded HERE (12 pages, 18Mb).
Tillotson HM-2A Specifications:
- Venturi Diameter: 27mm
- Throttle Bore: 34mm
- Fully adjustable High and Low jet, on track or off-track
- Butterfly Opening
- Patented Choke System
- Racing Class Venturi / Body Design
- Racing Class Inlet Needle and Seat Design
- Pulse Pump Connection
Recommended Carburettor Settings:
Rotax MAX (Senior/Masters):
L: 1'00''
H: 1'20'' - 1'25''
Rotax MAX (Junior):
L: 1'00"
H: 1'15'' - 1'20''
Mini MAX:
L: 1'00''
H: 1'10'' - 1'15''
Mini MAX:
L: 1'00''
H: 0'50" - 1'00''
DD2:
L: 1'00''
H: 1'30'' - 1'35''
Adjust first the High then the Low needle each in 1-2 minute increments. Find the High setting you like, then adjust Low needle and readjust High then Low as desired.
