O.S. Engine OS-1A203 Speed B2101-TY Track Optimised Engine with T2090-TY Header  [OS-1A203]

O.S. Engine OS-1A203 - O.S. Speed B2101-TY w/T2090-TY Header and Silencer
Price:
AUD$753.11
Brand:
O.S. Engine
Model:
OS-1A203
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Track-Oriented Design of the O.S. Engine OS-1A203 Speed B2101-TY

Made with racers in mind, the O.S. Engine OS-1A203 and Speed B2101-TY matched to the T2090-TY header deliver a controllable powerband and consistent throttle feedback. The package is aimed at minimising setup time while preserving tunable performance.

Key Performance Figures and Build Traits

The Speed B2101-TY is rated at 3.46cc displacement and produces approximately 2.61hp at 34,000 RPM, with an effective rpm range from 4,000 to 42,000 RPM. High precision in the crankcase and crankshaft machining contributes to smoother operation and reduced vibration on track.

Exclusive Restrictor and Matched Exhaust Components

This limited edition includes a custom 5.8mm carb restrictor designed around Ty Tessmann's championship setup to refine throttle and torque delivery. When combined with the T2090-TY muffler and M2002SC manifold, the result is improved low to mid-range acceleration suited to tight circuits.

Specifications

  • Displacement: 0.211 cu in (3.46cc)
  • Bore: 0.646" (16.4mm)
  • Stroke: 0.646" (16.4mm)
  • Practical RPM: 4,000-42,000 RPM
  • Output: 2.61hp @ 34,000RPM
  • Weight: 12.42oz (352g)
  • Mounting Hole Centers (Same Side): 0.83" (21mm)
  • Mounting Holes (Opposite Side): 1.4" (37mm)
  • Height (Bottom of Mounting Tabs/Top of Cylinder Head): 3.2" (82.6mm)
  • Width of Mounting Tabs: 1.8" (45mm)
  • Distance from Backplate to Front Bearing: 2.5" (64.5mm)
  • Crankshaft Size: UNF1/4-28
  • Crankshaft Length: 1.2" (29.5mm) outside of engine
  • Carburetor Settings: Preset at factory, minimal adjustments needed

The O.S. Engine OS-1A203 Speed B2101-TY is well matched to competitive racers who prefer a tunable but accessible nitro engine, with accessories that help focus power where it is most usable.

What mounting checks should I perform before running?

Confirm mount hole alignment, verify crankshaft play is within spec, and ensure header clearance from the chassis and bodywork before the first run.

How does the restrictor affect fuel economy?

The 5.8mm restrictor moderates air flow to improve torque, which can change fuel consumption patterns; monitor run time and adjust mixture if needed for endurance events.

Are spare parts readily available for this edition?

Common service parts like gaskets, needles and seals are available; the custom restrictor is specific to this run so check with suppliers for replacements or alternatives.

Should I change factory carb settings for high altitude tracks?

Yes, thinner air at elevation typically requires leaning the mixture slightly; make small adjustments and track engine temperature to avoid running too lean.

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