Tower Hobbies — Having Fun Since 1971
Powerful performance for weekend warriors.
1/8 scale buggy competition is as fierce as it gets. You want every advantage possible — and it starts with the 21XR-B Version II engine. This version of the 21XR-B power plant has been totally re-designed. It’s even more reliable, and the new 21J3-I carb is easy to tune. The aluminum cooling head ensures steady power even under harsh conditions. And when you're ready to move up to top competition, you can get up to speed with the 21XR-B Version II. This engine is upgradeable with high-performance O.S. Speed Parts, letting you realize your full winning potential. Equip your ride with the 21XR-B Version II, and start owning the podium.
- Engineered for up-and-coming 1/8 scale buggy club racers, with upgrade capability for competing at the highest levels.
- A dependable, low-maintenance engine that fits into most any modeler's budget.
- O.S. Speed parts are available for updating the outer and inner heads, crankcase, crankshaft and more.
- Includes P3 turbo plug.
The 21J3-I carb comes with two intake restrictors that can be swapped out quickly and easily for fine-tuning to meet track conditions. The yellow (7 mm) restrictor gives you more bottom end, while the red (8 mm) restrictor delivers more top end.
The blue-anodized aluminum cylinder head delivers superior cooling.
|Bore||0.64 in (16.27 mm)|
|Carb Type||O.S. 21J3-I slide valve w/7mm & 8mm restrictors|
|Displacement||0.213 cu in (3.49 cc)|
|Engine (Only) Weight||13.40 oz (380 g)|
|HP||2.45 PS 2.42 HP @ 33,000 rpm|
|Plug Type||Turbo P-3 Glow Plug|
|Product Height||3.4 in (86.5 mm) bottom of mounting tabs to top of cylinder head|
|Product Length||2.5" (64.5 mm) from backplate to front bearing|
|Product Width||1.8 in (45 mm) at mounting tabs|
|Recommended Fuel||10-30% nitro content, 20% recommended for break-in|
|RPM Range||4,000 - 40,000 rpm|
|Stroke||0.66 in (16.8 mm)|
|Total Weight||12.5 oz (353 g)|