Just tried adjusting the AFM. It was a little high but nothing much. Didn't change anything.
I checked the gaps of no. 7, 5, 3 spark plugs and all was fine at 0.8mm so I stopped there. Will check the others tomorrow.
Test drove it after doing the above and it still pops and farts and runs rough at cruise but you can redline it in 2nd gear and it pulls hard and strong right the way through.
So I'll change the leads tomorrow just to rule it out but otherwise all I can think of doing is refitting the old airbox and retiming it to suit and see if it runs fine like it did before I installed the snorkel

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