I am putting a Curtis Sparks MX pipe, Coolhead, getting port and polish, and a Delta V-Force reed valve all at the same time in a couple of weeks and was wondering how well the stock carb would do and if I had to run high octane race gas. I have been told that when you boost your compression up so high you have to run race gas. How high? My compression now is 170. How so the interchangable domes affect compression.

 

Try running 50/50 mix to begin with. If it doesn't make noise, run that mix. If not go go 100%. Alot of people run staight race gas and they don.t need it when a 50/50 mix will work amost as good.

 

The best thing to do is run a compression check after you get everything back together. I don't think you have to worry about race fuel unless your compression starts hitting over 200. Check out the latest edition of ATV Sport Magazine, they had a good article on compression and octane ratings.