Here goes. I've always been a OS guy since i've started racing nitro, however, i have admired the RB C6 also. So i had the opportunity to buy a C6 USA and a 192/2045 pipe combo for next to nothing but needed rebuilt and i'm off to the races. Bought a new p/s/r and ceramic bearings and sent it straight to Uriah for a mod job. Engine broke in well and ran like a top during break in and the 1st 2 races. Then performance started to wain and tune consistancy was non existant. This engine will run stellar for 5 min then abrupty change and go from mildly rich on the bottom to very lean and racey. After shutting it down after a run it sizzles inside like bacon frying. The best i can tell the head is supposed to use a .2mm (.008") and a .1mm
(.004"). I tried the 2045 pipe with the stock rb carb 1st, then put my fms carb and a 9853/41005 and lastly put a fresh speed carb and tried the 9886/41021 combo. I use OS plugs only and have tried a P3, P4, P5 and a P6. I know the potential of this engine as i have seen Murnan modded B9's run before and this is supposed to be slightly stronger on the bottom. If anybody that knows positively what the shimming should be with the rody head button this engine has i would greatly appreciate it. My next move is a conventional head button and for Gods sake i guess some lucky 7. Chris Peralta gave me the ballpark carb settings for this engine a while ago but mine won't come close to functioning with those settings.
Thanks, Rob.