#OS1EG01 - O.S. SPEED MAX-B21 Combo Set
What our customers say
A selection of recent five-star reviews, as written.
-
★★★★★
Ordered flishrc cobra. Communication was great. Ordered larger batteries but they were the wrong size. Olly shipped the right batteries and gave a refund for the difference I paid. Couldn't ask for more. Thanks for the help with the order.
Robert, 22 September 2026
-
★★★★★
Very helpful when the vehicle I wanted wasn't in stock. Very fast deliver too.
Anna Abbott, 17 September 2026
-
★★★★★
Excellent service speedy delivery and good customer service
GLYN, 10 September 2026
-
★★★★★
Great product and service. I enjoy buying from these guys. Thanks to radio-controllled.co.uk.
Paul Jordan, 3 September 2026
-
★★★★★
Dealt with customer services over an order I accidently placed, they were prompt and dealt with it will, completely refunded within a small window of time, thanks!
Oliver Galustian, 23 July 2026
-
★★★★★
Really good online rc store with some great products and sales on. The owner is very knowledgeable as well.
Simon, 19 July 2026
-
★★★★★
Product delivered promptly and in excellent condition 👍had very helpful and prompt responses from Olly to all my questions, I will definitely be using them again 👍
Mark Clucas, 30 January 2026
-
★★★★★
The customer service and advice were first class!
Steve Avery, 9 September 2025
-
★★★★★
The seller knew I was after one and very kindly informed me when they came back into stock so now have a Flywing Bell 206. Fantastic bit of kit. Well worth the wait.
Pete Goddard, 15 April 2025
-
★★★★★
Great service, car arrived fast and really well packaged. Also, I had a little problem....(which turned out to be me doing it wrong) but someone replied the same evening! Will definitely be buying from them again.
Graham Rousseau, 10 February 2025
Key Specs
About this product
O.S.Engine OS1EG01 – MAX-B21 3.5cc 1/8 Buggy Engine with Exhaust System Combo
Made for 1/8 nitro Offroad MAX-B21 is easy to use from entry-level users to sports users and has excellent cost performance. Based on the O.S.SPEED B2104 series engine, it has a well-balanced combination of smooth speed and power delivery and can be used in both on and off-road racing situations. Features:
The crankcase is based on the O.S.SPEED B2104 crankcase
Piston and sleeve is improved based on O.S.SPEED B2104
The connecting rod is the same as the O.S.SPEED buggy engines
Included Exhaust System for 1/8 Buggy (not GT): TB02 EFRA2089 (T2090) Pipe/Muffler and MB01-75 (M2000SC) Exhaust Manifolder
This engine will replace the MAX-21 XR-B VER.3 and MAX-21 XZ-B VER.2. Specs:
Displacement: 3.49cc
Bore: 16.27mm
Stroke: 16.80mm
Output: 2.6ps @ 34.000RPM
Practical rpm range: 4.000-41.000
Weight: 361g
Included:
P3 glow plug
Reducer Venturi: 6mm (Orange) & 7mm (Yellow)
Exhaust seal ring
Dust cap set: 3, 16 & 18mm
ITB02 EFRA2089 (T2090) Pipe/Muffler and MB01-75 (M2000SC) Exhaust Manifolder
Frequently Asked Questions
The MAX-B21 is designed for both entry-level and experienced users, so beginners can use it, though you'll need basic familiarity with nitro engine operation, tuning, and maintenance. If you're completely new to nitro RC, consider seeking guidance on starting procedures and glow plug use.
The combo set includes the 3.5cc engine, P3 glow plug, two reducers (6mm and 7mm venturi), exhaust seal ring, dust caps (3, 16, and 18mm sizes), and the exhaust system with both the TB02 EFRA2089 pipe/muffler and MB01-75 manifolder.
This engine is made for 1/8 nitro offroad buggies and includes an exhaust system specific to offroad buggies (not GT). It replaces the MAX-21 XR-B VER.3 and MAX-21 XZ-B VER.2, so check your buggy's manual to confirm compatibility with those models or contact us if you're unsure.
The MAX-B21 produces 2.6 horsepower at 34,000 RPM with a practical operating range of 4,000–41,000 RPM, providing smooth acceleration and speed suitable for both on and off-road racing.
Yes, this is an engine combo only; you'll need to source nitro fuel separately and ensure you have appropriate charging equipment for the glow plug included. Check the product manual for exact fuel specifications and charging recommendations.
What our customers say
A selection of recent five-star reviews, as written.
-
★★★★★
Ordered flishrc cobra. Communication was great. Ordered larger batteries but they were the wrong size. Olly shipped the right batteries and gave a refund for the difference I paid. Couldn't ask for more. Thanks for the help with the order.
Robert, 22 September 2026
-
★★★★★
Very helpful when the vehicle I wanted wasn't in stock. Very fast deliver too.
Anna Abbott, 17 September 2026
-
★★★★★
Excellent service speedy delivery and good customer service
GLYN, 10 September 2026
-
★★★★★
Great product and service. I enjoy buying from these guys. Thanks to radio-controllled.co.uk.
Paul Jordan, 3 September 2026
-
★★★★★
Dealt with customer services over an order I accidently placed, they were prompt and dealt with it will, completely refunded within a small window of time, thanks!
Oliver Galustian, 23 July 2026
-
★★★★★
Really good online rc store with some great products and sales on. The owner is very knowledgeable as well.
Simon, 19 July 2026
-
★★★★★
Product delivered promptly and in excellent condition 👍had very helpful and prompt responses from Olly to all my questions, I will definitely be using them again 👍
Mark Clucas, 30 January 2026
-
★★★★★
The customer service and advice were first class!
Steve Avery, 9 September 2025
-
★★★★★
The seller knew I was after one and very kindly informed me when they came back into stock so now have a Flywing Bell 206. Fantastic bit of kit. Well worth the wait.
Pete Goddard, 15 April 2025
-
★★★★★
Great service, car arrived fast and really well packaged. Also, I had a little problem....(which turned out to be me doing it wrong) but someone replied the same evening! Will definitely be buying from them again.
Graham Rousseau, 10 February 2025
