Hi speed2need
Have to agree with hussabutt here or maybe try Sindwinder and there Tri-metal sprocket.
Also tried the 42 pilot and 175 main on a ride at 5000-7200 ft. at 65-70 degrees and had boil over simptoms. The bike started and carborated very well at low throttle openings but I think it needs the 178 main to run alittle cooler, also checked the plug and it looks alittle on the lean side.
I can understand the thought to gear lower because my son road a 400 Fe 2000 model which has a lower 1st gear and this came in very handy on this ride.
Also I will take this opportunity to plug Linaweaver and his X2 cam, this is a really cool cam for this kind of riding.
Anyway let me know how you do with your gearing changes.
Thanks Fred