This is HPI's Nitro Star S-25 Engine With Pullstart.
This is the standard engine for the Savage 25 and the Savage SS
FEATURES: Slide valve carb with flat-head screwdriver adjustment on needle
ABC cylinder construction
Purple anodized head
Rear exhaust round port
Flowed and counterbalanced crankshaft
Machined pilot shaft crankshaft with collet preinstalled
Knive-edged billet aluminum connecting rod with dual bushings.
INCLUDES: Nitro Star .25 (4.0) glow engine
Air filter and replacement element
SPECS: Crankcase: 3.32" (from rear of case to front without shaft)
Height: 4.41" (from bottom of case to the top of the head)
Width: 1.81" (mount flange)
Mount Holes: 1.42" (measured from center to center width)
Mount holes: .82" (Between holes front and back)
RPM: Over 38,000 RPM
Horsepower: 2.5 @29000 RPM
Crankshaft diameter: 5mm (clutch bell area)
Crankshaft diameter: 6.7mm (threaded portion)
Crankshaft screw: 3 x 12mm caphead screw
Capacity: 4.09cc (.25)
REQUIRES: Glow fuel
Vehicle requiring a rear exhaust .25 engine.
OMMENTS: Replacement pull-starter is HPIG1428.