Club racers rejoice! The R21 engine delivers an unbeatable blend of power and value for 1/8 on-road racing. Its crankshaft and piston/liner are designed with premium performance and easy maintenance in mind, which makes it an ideal choice for beginners. Best of all, they can be upgraded with O.S. Speed parts when you want to step up to Spec-class competition. High performance. Low price. That’s what you can expect from the R21, only from O.S.
The perfect power plant for rookies and club racers!
Upgradable, newly developed crankshaft and piston/liner lets you transform the R21 into a Spec-class performer.
RP7 Turbo glow plug.
8.5 mm carb reducer.
Speed flywheel collet.
Exhaust seal ring.
Dust cap set.
0.213 cu in (3.49 cc)
2.75 PS 2.71 HP @ 32,000 rpm
Turbo RP7 glow plug
3.6 in (91.2mm) from backplate to front bearing
2.5" (64.5 mm)
1.8 in (45 mm) at mounting tabs
10-30% nitro content, 25% recommended for break-in