Header pipe replacement - My experience

[peters125]

I'll try the pics again!

[Gord]

I've got a YZF 750, I've never used it with an EXUP valve fitted, when I first got it I had it set up on a rolling road and removed and blanked off the EXUP valve.
It was fine with a bit of a flat spot about 5k, then I fitted some stainless down pipes, this improved the top end though it still had a flat spot.
Anyway I took it to Cornwall on the camper van and noticed that this flat spot was massive when I was two up on narrow Cornish roads.
I've sold the stainless pipes and fitted a set of standard down pipes with an EXUP valve fitted and working.
WOW, what a huge difference! It's like having a completely different engine in it now, I'm very pleased with it.

I'm glad yours us working well but I didn't realise how bad it was until I've now gone back to standard.

[Solorider]

An original exhaust is a 4-1 which will give a better top end at the expense of the midrange, sandy bike exhausts are 4-2-1 which give a boost to the midrange but a slight loss at the top end, the oe exhaust has the exup to give that midrange back.