Chugging at 3000rpm curvy

Hi guys

Had a little chugging on the bike, felt like the same chugging you would get if the engine was about to stall when stopping in 1st. Originally it was chugging at about 4500rpm but I had the bike serviced and the guy said the pilot?? Was a little off.

Said he cleaned etc etc and it would be sweet now.

I rode the bike home and it was great but today when going to work and it was warmed the chugging returned this time at 3000rpm.

The guy who looked at it is a sound mechanical guy and a family friend. So he wouldn't have said he looked and never bothered.

New spark plugs fitted. New air filter (k&n) and all fluids done.

I don't know what else to try.

Any ideas?

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Checked the chain tension?

Chain seems fine. I'm leaning more towards a lean mix. The idle speed is jumping but about 300 rpm and the then falling back to normal ever 2 seconds or so.

I add a little choke and it is a very consistent idle rpm I get.

Fair conclusion?

Rob

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[embee]

From what you describe it sounds like a fair assessment has been made. Applying a little choke richens the mixture, normally in a hot engine this will make it misfire and run like a bag o' cack but if it improves things then it's almost certainly running lean. Your chokes are obviously working OK so we'll rule sticking chokes out.

Idle (pilot) mixture adjustment is tricky on the SV because of where the screws are. You'd normally do it with the engine idling, but it's not easy on the SV without an angle drive adjuster tool (I do it with a thermal glove and squeezing my hand in there, but it's a bit warm!)

It'd be worth checking the diaphragms, slides, springs, needles etc, but it does sound rather like the idle/pilot circuit either set too lean or partially blocked.

Maybe try running some of that fuel cleaner stuff through it. Or is that all just a marketing ploy?

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