@grampi This post might seem a little patronizing, but I don't mean it that way...its just my simple minded way to approach logically resolving mechanical issues. I try to follow a principle called Occam's Razor (Among competing hypotheses, the one with the fewest assumptions should be selected) or in other words...the simplest solution is usually the correct one. This usually works for me. Having said that here is the way I would proceed in your case.
1.) Even though it seems unrelated I would check the simple things (fuses, vac lines, coil leads, etc) which it seems like you have already done and the dealership should have done, but may be worth checking again.
2.) You said TuneECU wouldn't do you any good because you don't have a laptop. My suggestion would be to get one. TuneECU doesn't require much computing horsepower, as a matter of fact you can run it from an android smart phone. Small netbook type laptops can be had for little money these days and the cable is $20. If you had access to tuneECU you could have either identified the TPS as a problem or eliminated it as a possibility. In addition you can read and clear trouble codes and perform other diagnostic chores with it. Folks on here will be glad to help you out with using TuneECU once you have it.
3.) Contact
@HansO on PM and give him all of the specs on your bike (intake mods, exhaust, etc). Hans has a library of tunes and can probably hook you up with something that is proven to work on other bikes with the same or similar modifications to yours. If he can't someone on here can. You will need TuneECU to load it unless you are running a Power Commander in which case you will need their software.
4.) Intermittent electrical problems are a b!tch to track down, and if this problem only appears after a test ride where say a loose connector gets jiggled around or a skinned wire makes contact with the frame it may take you quite a while to narrow it down.
5.) While it may seem that those on here sound like a broken record they are simply stating the most comment causes for your symptoms which are low tension coil lead, loose vacuum line, TPS, etc. I would make sure that each of the potential causes mentioned by others in this thread is double checked as they have mostly come from folks that have had similar issues and corrected them.
6.) If you still can't resolve the issue after the above, make a copy of your tune and find a dealer that you can work with and take the bike to him with no holds barred and let them fix the bike.
I wish I was closer as I would be happy to help you out. If you make it down to Texas any time soon throw that thing on a trailer and I will see what we can figure out.
