Redneck vent system.....
As mentioned, my new M2R is a very nice helmet, but hot with no vents. I've become a fair weather rider and put the bike away during the hot summer months. However we have our national dual sport (more of a 200 mile enduro........tight) coming up always in June, so this one is usually 85-90 degrees. Took my old, nasty, beat-up HJC out of retirement and modified it. I'm a sheetmetal worker and made two mini scoops out of alum........rivited them over the two forehead vents and drilled two 3/8" holes at the rear of the helmet, just below the crown. I should probably not have done this or recomended it, probably damages the integritity of the helmet, but I did. Incredible difference..........really flows some air.