Front cylinder cuts out on idle.

Evening all,

Hope someone can help with the following.
2007 rsv factory 9k miles.

After a year laid idle I stuck some new plugs and drained the fuel in the bike, all was well for about 10 miles until I lost almost all power. Bike sounded very rough so I took it home and realised the front cylinder was cutting off every 10 seconds or so and firing intermittently for a few seconds or so.

I checked the spark on the cylinder, all good.
Took off tank and completely cleaned it.
Checked all vac pipes inc the two small ones to the map sensor.
Replaced injector with a brand new one.
Played with the throttle body bleed screws which doesn't help at all.
No errors codes on the dash apart from oil pressure which I don't think is related.

It has a new battery also, it's still charging well on idle.

The bike will stutter badly to 4K rpm but seems to run smooth after that.
Any ideas? Been scratching my head for weeks!

Both throttle bodies look to be sitting 2mm or so out of the rubber boots but I can't feel any leaks around them.

Hi, I went out yesterday and as I started it the idle seamed lumpy and it has the same symptoms as your's up to 4k.
It's a factory 2005 I only just finished building it.
I am going to replace the sparkplug caps as they weren't that good and going back to NGK plugs at present it running on Brisk ones it only done a couple of hundred miles on them and it was running fine till yesterday.
I am baffled as you are to what it is,it goes really well above 4k I will let you know when I fit parts or if I come across anything.

Yep, HT cap was the problem. Even a temp donor from the fs1e parked next to it got it running.
Frustrating thing is it ran better than it ever has before, must have been dodgy for years!

Shows how important a spot ignition system is!

Hi, I hope it is the same for me, I have got some caps coming from eBay exactly same as the old ones £8, did fit original or something different. I am really hoping it is caps or the plugs and nothing to do with the Autotune or Pcv but something intermittent on low revs sounds like ignition. We will see if I am as lucky as you.

Here's a place on eBay probably cheaper than buying them from Aprilia and might be best to replace both. View attachment 6559

Put new caps and it runs like it has never before so much easier at junctions, smoother and no poping and banging. Like yourself it has never run better I also believe that they were breaking down since I had it. The bike is transformed and the Dynojet Autotune with the caps fixed made an extreme difference unbelievable grunt under 4k.