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Hiya Higgy...

feel free to rant BUT...leave out persuasive comments like "only a fool..."; there are valid resons not to change filters if you change fuel system components...like the injector or regulator - which is down-stream of the filter, anyway...

in the post he says he's changed the fuel filter several times...that's just unnecessary expense.
if the fuel flows at any reasonable rate it won't be "blocked" to the extent the engine will starve.

if the bike will run at "full gas" or even run well for 20 minutes then misfire...then clean up again (and most will accelerate well, too) the issue can't be a filter blockage..it doesn't make sense.

sure the filters are relatively cheap - but they're in a prick of a place inside the tank; they take at least 1/2 an hour to change out...if you're paying a workshop to do that work they're not so cheap after all...[as a side note - I moved my filter outside the tank to make it easier to replace and check pressure/flow...

it's not so bad if he's doing the work in his own back yard as "trial and error" but if he's PAYING a mechanic for parts and labour to swap out several filters to troubleshoot a misfire on a bike that otherwise runs well fairly simply he's not going to the right mechanic.
In any case - if the mechanic was worth his salt he'd have back-flushed the filter to see what the blockage grit was...

I have been down the track with an undiagnosed misfire; replacing "could be" problem components to trace the fault...you end up spending heaps on parts that were serviceable and hours of labour (either my own or some expensive Ducati tech)...so I guess I wrote the "forget the filters..." in case they were intending to continue with half-assed diagnostics...

cheers mate!

We are good and on the same page Just didn't want anyone to get the wrong idea and I certainly meant no insult to you..........If the fuel flow is good and you have a problem,it is fuel quality or a down stream issue or not a fuel issue at all and you need to look somewhere else.

if the bike will run at "full gas" or even run well for 20 minutes then misfire...then clean up again (and most will accelerate well, too) the issue can't be a filter blockage..it doesn't make sense.

in a word,some sort of contamination(water or dirt,rust), in the fuel system will often cause this sort of problem even on an injected engine bad fuel lines or tank ventilation are often overlooked.
Any time you change a filter, you should drain the contents and look it over.New filters need to be checked with air for good flow. Also, Checking the fuel flow in litres or gallons per minute will catch this sort of issue every time and is easy to do(carefully, I once set a corvette on fire )
And there is no excuse for any Tech charging you for anything that does not fix the issue,ever
I once ate 2 days of labor on a customers M5. The mis only occured on the track in the same corner intermitantly. He and several of his racer friends had been over the car as well as most of the shops in the area so I knew it was not going to be easy. The tank had been dropped,the electrical system had been gone over everyone was thinking fuel or some weird ground issue,including me.
even the tank ventilation system had been gone over looking for spider egg sacks, a known issue which usually gets found when the tank implodes.
Turns out it was a spark plug and they had been changed out once. The insulator around the center electrode was broken. Not just one,but two different plugs from two different brands. Everyone had pulled both plugs and inspected them. This plug when you inspected it looked fine and even an ignition trace showed no issues. but when each of us pulled the plug and looked it over we turned it upside down,this was enough for the loose insulator to wedge itself back in place at least until he hit the small bump on the same corner at the same track. The insulator on both plugs would then fall down and cover the center electrode and he would get a short lived miss till the insulator got blown back into its proper place. To this day I carefully inspect ever new part I install
Rant =off.
No worries
PS it does sound like an electrical issue he is having my guess would be the ignition module has a weak connection some where