Just dragging this back up because its been confusing me a while now, with a 4t does bolting on a more free flowing end can reduce the back pressure letting the scavenging of the cylinder more effective and therefore cause the bike to run rich?
I ask because it doesn't make sense to me that you would need to up-jet upon fitting a more free flowing end can, yet the "burbling" that results from not re-jetting is caused by excess fuel being dumped into the exhaust, surely that is an indication of it running rich, therefore requiring DOWN JETTING, not a symptom of running lean, which would require UP JETTING.
Or am i missing something here?
Trying to get my head around this 4t malarky after 6 months of near obsessive research into 2ts is baffling!
