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O.S. - OSMG2080 OSM12520 12520 531028020351 4531028020351
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O.S. 25XZ (P) ABC w/21JN Slide Carb
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O.S. 25XZ (P) ABC w/21JN Slide Carb
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On-line Videos: Video 1 (95.8 MB) Video 2 (YOUTUBE)
Instruction Manuals: Manual 1 (2.4 MB)
Tower Catalog Page: 202

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Possible Substitutions

Tech Notes
This is the 2-stroke O.S. Max 25XZ (P) 1/8 scale Truggy Engine.

****** Because of the expressed racing nature of this engine, ******
****** it is NOT covered by the O.S. 2 Year Warranty ******
****** per page 8 of manual. ******


Designed for 1/8 scale truggy racing competitions
Meets ROAR regulations
ABC piston and liner construction "A"luminum piston fitted to a
"B"rass cylinder liner that is "C"hrome plated
Three needle 21JN slide valve carburetor
8mm red carb insert for smaller tracks that restrict air intake
Ten fin blue anodized cooling head with inner head button
P3 ultra hot turbo glow plug


O.S. Max 25XZ (P) Truggy Engine with instruction manual, 8mm carb
reducer, exhaust gasket, dust cap set, instruction manual and P3
turbo glow plug


Fuel: 10-30% nitro content (20% for break-in)
Air Filter: MSFG1660
Exhaust system depending on vehicle, see COMMENTS
Track equipment


Displacement: 0.25 cu in (4.09cc)
Output: 3.1 PS, 3.06 HP/33,000 RPM
Bore: 0.689" (17.5mm)
Stroke: 0.669 cu in (17mm)
Practical RPM Range: 4,000-39,000 RPM
Weight: 13.05oz (370g)
Distance between Mounting Holes Same Side: 0.83" (21mm)
Distance between Mounting Holes Opposite Side: 1.4" (37mm)
Length from Backplate to Drive Washer: 2.6" (65.6mm)
Width of Mounting Flanges: 1.8" (45mm)
Width of Crankcase Below Mounting Flanges: 1.2" (31.6mm)
Distance from Crankcase Center to Drive Washer: 1.7" (44mm)
Height/bottom of Mounting Flanges/top of Cylinder Head: 3.7" (93.2mm)
Height/bottom of Crankcase/top of Cylinder Head: 4.3" (109mm)
Needle Settings: Preset at factory, start engine as is. If
adjustments are ever required, make them in small increments.
High Speed: 3.5 turns out from fully closed
Metering Needle (low speed): Rotary: flush with carb body
Slide: Flush then 1/2 turn in
Throttle Stop Screw: .5mm out from fully closed


The O.S. Max T-2060 WN Speed Tuned Pipe OSMG2939, OSMG2938
is an ideal exhaust system for the 25XZ.
Flywheel sets are required (OSMG2648 for Mugen, OSMG2649 for Kyosho,
both sold separately) for certain truggy models.

jxs 02/15/10

– If you need more information, use these O.S. resources –
Web Site:
Phone: 217-398-8970
  Postal Address:

Click here for Units of Measure Conversion Calculators

Accessories Needed
This is the O.S. Max 25XZ (P) Competition 1/8 scale Truggy Engine. FEATURES: 10-fin cooling head, 21JN slide valve carburetor w/8mm reducer, P3 turbo glow plug REQUIRES: 10-30% nitro fuel, air filter, exhaust system, track equipment

Accessories for the O.S. 25XZ (P) ABC w/21JN Slide Carb

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Subtotal for this Group of Accessories: 38.36  
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