this is what happens when you live in an area that has 9 months of winter!

there is an o-ring groove on the inside, the bore of the
cooler fits very closely to the OD filter (closer contact better heat transfer), it also fits very close on the bottom of the filter as well, the extra material at the bottom of the cooler was left to provide a place to put the fins on the bottom. The actual side wall thickness of the cooler (not counting the fins) is only .100 inch. It still should be pretty rock resistant.

next oil change time there will be a little bit more machining done of the bottom fins.

05 speedmaster - 1100cc, 11:1 racing pistons, Carillo rods, thunderbike cams, ported and polished head, 2mm over intake and exhaust valves, Barnett kevlar clutch, scepter pipes, oversize manifolds, 45mm HSR's, TTP stage 4 firestarter