Intermittent fault. Bike won't rev past 6000rpm

[robbo]

Roxburd, It's bang on 6k in any gear. Feels exactly the same as hitting the limiter. If you rolled off a touch it would run ok. As the rev counter registers fault codes,exup valve,tps etc I did wonder if I located the single wire between the rev counter and igniter, cut it and rejoin with crimps. If the fault reoccurred I could snap this link apart and see if the bike would run ok with no rpm indication. Changing the clocks was on the list of possibilities for the other forum member who had this problem, but as I mentioned earlier, he'd had enough and sold the bike. This is one scenario where the ability to plug in diagnostics would help.The fuel line was checked when I changed the filter, and the exup overhauled 5 or 6 weeks ago. Plugs are about 2 years old, bike only used April to Octoberish. I'll change the regulator as not too expensive in the scheme of things, but does seem a bit "poke and hope", whereas I much prefer a logical approach. Thanks for your suggestions.