Pilot screw adjustment.

[riktherider]

Right, had a bit of a hassle getting one of the pilot screws out of the carbs as the head had got shagged (seems a common problem with the screws in the carbs) its been running rich for ages, and havent got around to buying new carbs as the screw was jammed, but recently it has really started to loose power. wont even lift the front wheel when throtteling it in 1st gear! i think ive been running it rich for too long, and buggered the piston rings but will check that later...first things first get teh carbs sorted. Started cleaning the carbs but need to know how many turns out (from completely tightened) for the standard setting, then i can work from there and set it to my requirements.

cheers

[Robw#70]

About 2-1/2
But theyre idle screws and only effext the idle circuit and initial throttle opening, check the choke cables and plungers as its the most common issue on an sv

[riktherider]

well those screws are well and trully fudged, but that hasnt really been a problem. like i said, its been running lean for ages, but still pulls really really well, but recently, its lagged in power loads. so i just need to set everything to its initial settings, to eliminate things bit by bit, then figure out whats wrong. ill try to get the screws out after work tomorrow with a torx, but i really dont think they are budging!

[Daveog]

I've just removed the pilot screw while cleaning the first carb for the first time. I hadn't realised you had to record the setting, until I read the manual properly after I had removed it. :smt102 Lesson learned - read the instructions first!

So, my question is - am I correct that to reinstall you tighten the screw in all the way and then undo it approximately 2.5 turns? I'm going to pay attention to the next one and see what setting that was at and hope, hope, hope that the setting was the same.

[Marchetti]

Right, had a bit of a hassle getting one of the pilot screws out of the carbs as the head had got shagged (seems a common problem with the screws in the carbs) its been running rich for ages, and havent got around to buying new carbs as the screw was jammed, but recently it has really started to loose power. wont even lift the front wheel when throtteling it in 1st gear! i think ive been running it rich for too long, and buggered the piston rings but will check that later...first things first get teh carbs sorted. Started cleaning the carbs but need to know how many turns out (from completely tightened) for the standard setting, then i can work from there and set it to my requirements.

cheers
Adjusting the idle mixture screws is a bit tricky. Ideally you should set them at 2.5 turn out from closed position and then readjust while the bike is running with a vacuum gauge hooked up. Typically you would just turn in the mixture screws until it stumbles, then turn out the screws until you reach maximum vacuum. Make sure you get a very short skinny screwdriver to reach the idle mixture screws though.

[Daveog]

Adjusting the idle mixture screws is a bit tricky. Ideally you should set them at 2.5 turn out from closed position and then readjust while the bike is running with a vacuum gauge hooked up. Typically you would just turn in the mixture screws until it stumbles, then turn out the screws until you reach maximum vacuum. Make sure you get a very short skinny screwdriver to reach the idle mixture screws though.

Ah! Could be a lightbulb moment for me here. Thanks Marchetti. When I hook up the synchronisers, would these be the adjusters I'll be heading straight for?

[Marchetti]

Ah! Could be a lightbulb moment for me here. Thanks Marchetti. When I hook up the synchronisers, would these be the adjusters I'll be heading straight for?
Daveog, glad to help. syncronizing the carbs is a bit different, after you get the idle A/f sort individually you would hook up your vacuum lines to the sync tool and use the adjuster on the left side of the carb linkage to get them both pulling equal vacuum at idle. Then readjust your idle and bam, the front wheel will be in the air in no time. I just redid my sv650 and it runs way better than the stock carb tuning. The bike is stock aside from a desnorkled air cleaner and a staintune slip-on. I ran 145main jets, 17.5 pilot jets(all mikuni), two shims on the jet needles and tuned just as I explained. Good luck!

[Daveog]

Thanks Marchetti - fingers crossed I can do it!

[Bibio]

or get yourself a gunson colortune. if you do remember to get the correct plug thread fitting.

[johnnyrod]

Dave just set it to stock settings (2.5 turns out from lightly seated), things have to be wildly wrong for you to need otherwise. I would take Marchetti's advice with a pinch of salt - what other mods has the bike got? That much upjetting all round really would be to suit a heavily-modified engine, and TBH I'd be looking for a good dyno operator do do that. FWIW our American cousins seem to run huge jets in their bikes, I don't know why.