O.S. Speed B21 Adam Drake Edition Engine

Tower Stock# OSMG2066  •  Manufacturer Stock# 1A20C
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Notes from our tech department:
This is the O.S. Engines Speed Tuned B21
Adam Drake Limited Edition 1/8 scale Buggy and Truggy Engine.

****** Because of the expressed racing nature of this engine, ******
****** it is NOT covered by the O.S. 2 Year Warranty ******

FEATURES

Exhaust timing is 2 degrees higher than previous B2101 for greater
top speed
21J3(B) slide valve carburetor with 6.5 and 8mm Carb Reducers
suitable for buggy and truggy use
Silicone filled crankshaft with DLC (diamond like coating) with
two balanced tungsten weights and optimal intake timing for a
smoother power transition from low-mid-high speeds
Special cylinder head in black with Adam Drake graphics in white
Newly designed three-port cylinder liner

INCLUDES

Speed Tuned B21 Adam Drake Limited Edition Buggy and Truggy Engine
21J3(B) Carburetor with 6.5 and 8mm Carb Reducers
O.S. Speed P3 Gold Glow Plug
3mm, 16mm and 18mm Dust Caps
Exhaust Seal Ring
Instruction manual

REQUIREMENTS

Glow Fuel: 10-30% nitro content, 20% recommended for break-in
Exhaust System such as the O.S. T-2090SC Tuned Pipe System

SPECIFICATIONS

Displacement: 0.213 cu in (3.49cc)
Bore: 0.646" (16.4mm)
Stroke: 0.652" (16.55mm)
Practical RPM: 4,000-42,000 RPM
Output: 2.65PS 34,000 RPM, 2.61HP @ 34,000RPM
Weight: 12.45oz (353g)
Distance Between Mounting Hole Centers Same Side: 0.83" (21mm)
Distance Between Mounting Holes Opposite Side: 1.4" (37mm)
Mounting Hole Diameter: 0.12" (3mm)
Height Bottom of Mounting Tabs/Top of Cylinder Head: 3.2" (81.5mm)
Height Bottom of Crankcase/Top of Cylinder Head: 3.8" (97.1mm)
Width at Mounting Tabs: 1.8" (45mm)
Width of Crankcase Below Mounting Tabs: 1.2" (31.6mm)
Distance from Backplate to Front Bearing: 2.5" (64.5mm)
Distance from Center of Crankcase to Front Bearing: 1.7" (44mm)
Distance from Center of Crankcase to Backplate: 0.81" (20.5mm)
Crankshaft Size: UNF1/4-28
Crankshaft Length: 1.2" (29.5mm) from front bearing
Carburetor Settings: NOTE carburetor is preset at factory and
requires only very small adjustments
Needle Valve, 3-1/4 open from fully closed
Mixture Control Valve, Flush with carburetor body
Metering Needle, Flush with ball link body
Throttle Stop Screw, Approximately 0.5mm

jxs 02/08/18
ir/jxs

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