Spec2 Performance Combinations
I found this table in a Spec2 catalog. Recommendations are for Yamaha’s RD400′s and RD350′s.
This information is probably 25-30 years old. Three upgrades that might not have been around back then were head squish band adjustments, electronic ignitions and newer carbs such as the popular Keihin PWK 28′s. Besides those items, the information is still relevant.
Gary Shumake at Spec2 is still in business, despite his website not having been updated from the late 1990′s. He’s busy, not easy to get ahold of and it takes awhile to get your work done with him. However Gary’s work is very good. To get ahold of Gary, his phone number is (747) 257-5129. If he doesn’t answer, leave a message and wait for him to call you back.