GRiSO dies on constant throttle and a UJ question to boot

Hi All,
Just back from the Ragged Fringe and several new developments have appeared since the GRiSO's faultless trip down to Adelaide and back earlier in the year. Number one is the bike is now intermittently dying, (losing spark, fuel blockage, whatever?) when you are on a constant throttle usually in the higher gears. It also happened a couple of times when I went to overtake, twisted the throttle for a bit of oomph and then, lost revs. If you change down, then give it a handful after it happens then it goes away for a bit. Interestingly, between Singleton and Gresford, it didn't happen at all, when earlier between Rylstone and Singleton it was a PIA. It returned again from Dungog to Gloucester. Any clues would be appreciated.
Also, how do you know when the UJ is on the way out? I noted on the way home in down shifts in lower gears when coming off the throttle, there is a distinct click feeling in the right footpeg.
Other than that I blew a fork seal and the RHS rocker cover gasket is leaking.
ta
Darrell (V11)

It sounds like what I was experiencing on my GRiSO 1100.
I did several things to remedy it at the same time so I am not certain which was the primary cause.

I removed the tank and pulled out the fuel pump/filter assembly.
I wire brushed the filter assembly with a brass bristle brush. There was a lot of crud and corrosion on the assembly.
I replaced the fuel filter and the hoses with SAE 30R10 submersible hose and fuel injection clamps.
I cleaned the pick up screen which was quite clogged.
I flushed out the tank several times til it was absolutely clean.
I cleaned out the two tank drain lines.
I removed the canister.
I put rubber caps on the intake manifold nipples.
I also replaced all the fuel injection hoses with SAE 30R9 hose and FI clamps. I did not want to use the OEM plastic molded on hose.

The bike has been running great since.

Side stand switch?

Do you have any codes in diagnostics? Maybe just bad fuel. Find out which, fuel, fire, air. Till then you're pissin in the wind.

Usually u joint vibrates if it's going out like your boots won't stay on pegs.

No diagnostic codes at all. I did all the fuel filter, injectors and plug caps last year. That leaves the side stand switch. Hope its that simple
Ta