- Joined
- Jun 30, 2012
- Messages
- 13,261
I have a question about Exup. Does anyone here have experience with it on modern bikes ? I'd be interested to know whether the exhaust cam timing on models of bikes fitted with Exup is very different from when the motor does not have Exup. I cannot understand how it increases bottom end, if it is a standing wave effect. One comment I've read was about the much lower noise levels when it is fitted. When I built the 850 motor, I advanced the cam by 12 degrees and got huge torque, however even with the 2 into 1 exhaust, the noise levels are horrendous. Another person on this forum corroborated that this happens when the 850 cam is advanced. Perhaps the modern bikes use more advance on their exhaust cam and use the Exup valve to control the noise ? I was told by one competent tuner that the modern bikes are faster when the Exup valve has been ditched.