Stalling/stumbling issue

I have previously had trouble with my Gen 6 (still under warranty!) stumbling under certain conditions, and have taken it to the local stealership where, predictably, they couldn't find anything wrong.
I then installed a Bazzaz Z-Fi unit, in the hope that it would sort out the issues I was having and indeed I had a few weeks of trouble-free riding.

Unfortunately, the problem has returned. - When I go to ride away, sometimes there is a huge flat spot and total lack of throttle response; the bike won't rev past 5000 rpm and feels like it is running on two cylinders. This lasts for between 5 and 10 seconds.

Another recurring issue is when I slow down, e.g. for a set of traffic lights, the engine idle rpm drops to below 1000 rpm and then the engine cuts out completely. If I put the bike into neutral it will start straight away and maybe not replicate the fault again that day.
I can actually see the rpm drop down low and I have no clue why this is happening, especially as the idle has been set for around 1200. - How can the idle drop below the rate for which I have set it?!

My Dad suggested that perhaps it might be a fuel filter problem, but I've only done 10,000km and I'm careful about where I get my fuel.

Any ideas?

 

I had similar stumbling issues with my 2006 and installed a Power Commander V with a downloaded custom map for same mods from a VFR rider and it resolved the problem. What map is installed on your Bazzaz? The map is really what it is all about, the device is only as good as the map allows it to be.

 

It's their own generic "VFR with aftermarket exhaust" map. However, I don't think it's the map that is the problem, as I was having these issues prior to installing the Z-Fi.

 

stepper motor?

 

No idea what you're talking about, guy.

 

Just trying to help here. ISCV = idle speed control valve / stepper motor. These went bad on a certain english made bike back when I was working on them. Along with this the TPS= throttle position sensor would be bad too. It was a question of how much voltage was going to it, and sometimes could go out of adjustment if someone was washing the bike and bumped the ISCV.

I believe your manual for this bike is around 100 pages long? my gen three bike only has 3,4 pages regarding the carburetors...

Good luck...