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Competition Marine Designs, Inc.
Ph: (386)330-2420

Bushed Drum Housing

Steel Rod with Needle Bearing and Top Bushing

Strong well designed Crankshaft with 8mm Journal

8mm Shaft Threads

Bolt pattern same as: Picco, CMB, K&B, OS MAX, and Rossi
Bore: 27.0mm
Stroke: 24.0mm
Rod Length: 43.2mm
Carburator: 14mm
Displacement: 13.7cc
RPM: 22,000 - 27,000
Horsepower: 5.5 - 6.9
The new MAC 84's currently available now have an improved Piston / Liner. The New MAC 84 Piston/Liner set has an improved exhaust port and the piston has some skirt removed. The new drum valve is ramped to improve flow and reduce intake tract volume. The complete package results in more total power added to the full rpm range of the MAC 84.

Click on the images below to view larger images.

Current Records
IMPBA 30cc Hydro SAW - 120.58 mph

NAMBA 30cc Mono 1 mi. Racing record - 83.49 sec.

NAMBA 30cc Mono SAW - 70.31 mph

NAMBA District 19 Champion X Mono and X Hydro

NAMBA National Champion TWIN Hydro
Use Brown 84 pipe or AB 67 pipe.

Use either pipe with the MAC 84 Header (18mm I.D.)

Set pipes as recommended on pipe page.

Head Clearance - .010" to .013"

Nitro - 40% to 60%
Parts & Price List
CLICK HERE to open our price list for the MAC 84 engine, and components.

To view our price list, you must have Adobe Acrobat PDF Reader installed on your computer system. If you do not have it installed, CLICK HERE to download it for FREE.

Mac 21 | Mac 45 | Mac 67 | Mac 84

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