Engine stumble

[MaxMidnight]

Part of the art of diagnosis is establishing what isn't causing the issue.

A compression test, or better still, cylinder leak-down, would rule that out as a culprit.

If that is OK then (warning! MM stock answer #3 approaching) then get a baseline dyno run so you know exactly what the fueling is doing.

Having done this you will have facts that will, if all has checked out OK, point to the ignition system that is causing the problem.
Your diagnosis can proceed from there.

PS What does the Stage 6 carb upgrade consist of... I'm familiar with S2 and S7 but not 6.

 

[Parminio]

Time for a pro in the Vmax world to take a look. How much $$'s to have them done properly ?

You can get @dannymax or @one2dmax to do them. I think they charge around $600.00 but you'll have to verify with them. Both of them do excellent work and they WILL be right when you get them back.

But before you bother with that, do what @desert_max said and do a comprehensive compression check on the bike. All the carb work in the world isn't going to help you if you've got compression issues.

 

[sdt354]

Got to question the carbs, because they are high probability on our bikes, when this kind of thing occurs. Piolet jets need to physically be cleaned. Wire or drill bit twisted through by hand. Or jets replaced with OEM. Float levels-wet check, and sync are critical. I'd absolutely do a leak down or compression check, seeing as the motor was worked on, but even if it weren't.