Product spotlight

NEW AF MAMMOTH HEAD

These new mammoth Lambretta heads from AF Rayspeed are a direct replacement for the standard sized cylinder heads but offer a significantly larger heat sink. The improved cooling results in a lower running temperature.

This has offered an increased safety margin to help engines better resist seizure in adverse conditions. AFR noted on servicing engines fitted with these heads that top ends are cleaner and in better condition than their counterparts. They attribute this to the two-stroke oil benefiting from the slightly lower running temperature.

The head will initially be available to suit 200cc (66mm), 225cc (70mm) and 250cc (72mm). A small block variant for the RB20 will follow soon.

The main design features of the New AF Mammoth Head in comparison to a standard head are: 1: Significant increase in the surface area for heat transfer. More and larger fins with fins on the underside of the head as well. 2: Holes between the fins around the circumference of the head to improve air flow. 3: Around 67% increase in the mass (880g to 1470g) over a standard 200 head, making the head more thermally stable. 4: Temperature sensor mounting point cast in to the head, to suit SIP/KOSO type sensors. 5: Cut away section to allow a standard clubman to fit with the bigger head. 6: Combustion chamber designs optimized to 7000rpm with compression ratios of 10:1 with a 1.2mm squish clearance. Alternates are available through machining.

These heads are obviously not a necessity as engines without these heads have been, and continue to be reliable. However they do improve the cooling in comparison to the standard head which leads to a typical 20ºC to 40ºC drop in running temperature, and an improved resistance to sudden changes of temperature. This may save an engine from a seizure and will improve the performance of the two-stroke oil.

AF Rayspeed Tel: 01944 710693 Email: af@rayspeed.demon.co.uk