Some may have noticed that the Hammarhead Jack Pine Scrambler has no oil cooler! – This being a bit of a revelation for many of us, I emailed James at Hammarhead.
The oil cooler was the crux of this build. Initially I was committed to a minimal cooler using a Spurgin heat exchanger but could not achieve the lean effect I wanted. My brother’s encouragement (at times dangerous but always fun) pushed me to do the final build without it. Before I pulled the trigger, I talked with Bill Himmelsbach (http://www.eurosports.net/staff.asp) about his scrambler builds. 
Bill knows these bikes inside and out and assured me that the oil cooler loop is independent from the lubrication circuit and that capping the feed does not stress the pump. He runs a big bore kit and mild cams without a cooler. After 3000 miles (including a track day and a flogging by the moto journalist Alan Cathcart), 
Bill disassembled the engine and saw no unusual wear. Furthermore, Bill said there was no color change around the piston wrist pin, an area that turns a telltale gold tint with overheating. That said, I offer the Spurgin cooler set-up as a no cost option. I do not run one on the development mule, but plan to install it when the bike is prepared for my Delhi to Leh-Ladakh ride next spring.
Bill knows these bikes inside and out and assured me that the oil cooler loop is independent from the lubrication circuit and that capping the feed does not stress the pump. He runs a big bore kit and mild cams without a cooler. After 3000 miles (including a track day and a flogging by the moto journalist Alan Cathcart), 
Bill disassembled the engine and saw no unusual wear. Furthermore, Bill said there was no color change around the piston wrist pin, an area that turns a telltale gold tint with overheating. That said, I offer the Spurgin cooler set-up as a no cost option. I do not run one on the development mule, but plan to install it when the bike is prepared for my Delhi to Leh-Ladakh ride next spring.
Really interested in doing this to my own scram, but Im going to wait and see how their bike does first
