Thought I’d have a look at exhaust valve today and found that the servo is not functioning. Valve remains in open position of course by default. Previous owner had a Rexxer tune done to the bike , so is it likely the exhaust valve function / servo could have been turned off in this state of tune, as there are no errors on the dash at all and I don’t see any eliminator devices installed ? To be honest I hadn’t noticed that the servo was not cycling with ignition on. Guess my hearing is not what it was The bike runs great , however what I do find is that in touring mode the throttle response is very twitchy. It’s almost like an on/off switch rather than a throttle at low revs. Nothing , nothing then it’s on.... and off we go Other riding modes are much smoother , but of course I tend to use touring most of the time which is a bit of a pain. So I had thought that the exhaust valve was maybe the issue at low revs causing effect of heavier engine braking , but obviously not with what I have found. Sorry for long post , but any insight to exhaust valve function will be much appreciated
There are probably plenty of threads on this subject but my factory trained mechanic told me it's purely there to get the bike through noise regs. It isn't a power valve. He removed mine completely and it goes (and sounds) great.
What engine mode setting do you have it in when in Touring Mode - Hi or Soft/low ? Hi is for sports mode and is immediate throttle response Soft is for touring with a slower throttle response.
Doesn't sound right. If it was in sport, may be, as that can be a little snatchy but I have had two 1200s and both had more lag on touring (DVT way more than the previous model).
Yep it is a bit strange. I guess it must just be the way the Rexxer mapping has been set up. Might just have to revert back to standard engine mapping, and then deal with what is happening with the exhaust valve again.
It may be that the previous owner had other ideas about touring mode and opted for an MPG mode for cruising. Mine lived in sport mode and out of all the modes, touring would have been my least used.
I found that the high engine setting worked better in touring mode, takes away that lag and unpredictablity, they’re both full power settings after all
It’s pretty much a given that the Rexxer map will disable the exhaust valve. Regardless of mapping, there’s only one fuel map in the bike. The different modes simply alter the relationship between throttle twist and butterfly opening. In sport, the relationship is linear. 10% twist, gives 10% throttle opening, 30/30, 50/50 etc. In touring, that relationship is softened for the first 50% or so of twistgrip rotation so the butterflies open less, softening up the throttle response. The other two modes are similar, but the lower power output is obtained by restricted the opening, even with the twistgrip fully open. I personally don’t get on with the softer throttle responses, on any of the fbw bikes, for reasons you seem to be experiencing.
Thanks for all replies. Turns out the TPS was out of whack by around 7 to 10%. Therefore throttle response way out. It's like a different bike now it's been adjusted. Unbelievable.
