This is the Speed Tuned 21XZ-B Speed Spec II ABC 1/8 scale Buggy Engine from O.S. Engines. ******Because of the expressed racing nature of this engine,****** ******it is NOT covered by the O.S. 2 Year Warranty****** ******per page 1 of manual.****** FEATURES: DLC coated crankshaft with silicone filled intake passage for improved fuel flow ABC piston and liner construction "A"luminum piston fitted to a "B"rass cylinder liner that is "C"hrome plated 21J2(B) slide valve carburetor with three carb reducers that restrict airflow helping to increase the amount of torque produced Black anodized crankcase Ceramic rear ball bearing INCLUDES: 21XZ-B ABC Buggy Engine with Slide Valve Carb, P3 Turbo Glow Plug, Exhaust Seal Ring, two Dust Caps, Instruction Manual and 6mm, 6.5mm and 7mm Carb Reducers REQUIRES: Fuel: 10-30% nitro content, 20% recommended for break-in Exhaust System: Depending on vehicle Glow starter, fuel tubing and track equipment SPECS: Displacement: .213 cu in (3.49cc) Output: 2.65 PS, 2.61 HP/34,000RPM Practical RPM Range: 4,000 - 42,000 Bore: 0.641" (16.27mm) Stroke: 0.661" (16.8mm) Weight: 12.52oz (355g) Crankshaft Size: UNF1/4-28 Distance Between Mounting Holes Same Side: 0.83" (21mm) Distance Between Mounting Holes Opposite Side: 1.45" (37mm) Height Bottom of Mounting Tabs/Top of Cylinder Head: 3.4" (86.5mm) 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 Crankshaft to Front Bearing: 1.7" (44mm) Distance from Center of Crankshaft to Backplate: 0.81" (20.5mm) Carburetor Settings, NOTE carburetor is preset at factory and requires very small adjustments Needle Valve: Approximately 3.5 turns open from fully closed Throttle: Approximately 0.5mm open from factory setting with reducer removed Metering Needle: Rotate until slotted head is 1.5mm away from ball link body Mixture Control Valve: Rotate until slotted head is flush with carb body jxs 02/25/13 ir/jxs