Rob, what size pipework are they. I have been talking with some guys recently who have been tuning 851/888 race bikes for private use, they maintain that 45/50 - 45/54 - 50/54 configs are the best to use with vipers. the 50/54 combinations works very well on the 926cc engines. They have also been trying different size balance pipe sections with good results. will probably want to get one for the sps. cheers robin |