O.S. 21XZ-B VII Off-Road Competition Buggy Engine

O.S. 21XZ-B VII Off-Road Competition Buggy Engine
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This is the O.S. 21XZ-B VII Off-Road Competition Buggy Engine. The 21XZ-B VII is light, cool running, with a low CG. Delivering power comparable to the Speed Spec II, the 21XZ-B VII exceeds expectations at a lower price. 1/8 scale drivers looking for a performance advantage will find it with the 21XZ-B VII powerhouse!

  • Performance that rivals that of the acclaimed Speed 21XZ-B Spec II
  • Shares the same piston, liner and con rod as the Speed version
  • Lightening holes in the cylinder head reduce overall weight
  • Other enhancements include a lower CG and improved cooling
  • A 22B2 single needle carb makes tuning a breeze
  • Optimized power band
  • Silicone filled crankshaft with tungsten counter weights
  • Blue anodized head
  • Incredible throttle response
  • 7mm carb reducer is included
.213 cu in (3.49 cc)
Bore: .641 in (16.27 mm)
Stroke: .661 in (16.8 mm)
Practical RPM: 3,000-41,500
Power Output: 2.7 hp @ 34,000 rpm
Weight: 12.77 oz (362 g)
Includes: 2282 carburetor, 6mm and 7mm carb restrictors, P3 glow plug, exhaust seal and dust cap set

This product was added to our catalog on July 11, 2014

Thursday, May 31 2018 (about 2 years ago)
O.S. 21XZ-B VII Off-Road Competition Buggy Engine
This engine is pretty awesome! It is really designed for a truggy but is also very good in a buggy. I’ve had my engine for about 8 gallons and here’s what I have to say.

The engine has tons of power and is plenty of punch.
At about 6-7 gallons the rear bearing was crunchy while the front was still pretty good. I replaced both.
Also at the 6-7 gallon mark compression was very good. I got mine repinched and I put a new rod in it so it wouldn’t break after being repinched.

The thing I like about the o.s. Engines is that as long as you do maintenance on these things and get them repinched every so often, and new bearings, these engines will last forever.
Verified Owner
Monday, May 2 2016 (about 4 years ago)
O.S. 21XZ-B VII Off-Road Competition Buggy Engine
Great engine -- intermediate to pro -- this engine holds a tune and has great power (bottom and high). Pair it with a 2090 pipe. Can't beat the price for OS quality.
Thursday, May 5 2016 (about 4 years ago)
O.S. 21XZ-B VII Off-Road Competition Buggy Engine
This engine the best for offroad and onroad for price nice
Verified Owner
Friday, May 29 2020 (5 months ago)
O.S. 21XZ-B VII Off-Road Competition Buggy Engine
It's an O.S. engine. I never should have tried to go with a cheaper engine. Easy to tune, behaves, and so far the break-in process has been flawless. It's running a little cold if you follow the direction, so I'm using my thermometer to lean it out after the first couple tanks. Still idled fine being run rich for break-in though.