S3 won't idle

[robert1]

all stock 75 s3 wont idle, choke works on 2 cylinders. If I use throttle to start, centre cylinder runs. If I pull the carb slide cable out of the housing, the other cylinders will fire. If I pull the carb cable up and hang it over the side of the housing, I can take it for a ride, although it still won't idle. Checked all jets, they seem ok. Something seems to be affecting all 3 cylinders. Any thoughts would be appreciated

[Curtis]

Did you just pull this out of a barn?

Pull the carbs and clean and rebuild them
Get the chokes working properly
Set the timing and set the point gap - make sure the points cam isn’t all rusted and pitted.

[Curtis]

I was not trying to sound facetious in my post - however from experience if you need to monkey around to get it running and take it for a ride - it needs to be addressed before any detrimental problems occur

[robert1]

Np Curtis, I understood. I've owned this bike for 11 yrs, it's mint, 8000 miles. Usually runs great. I've tried the usual culprits, as you suggested a couple of times before I posted. Seems to me, the more I think about it, prob gas flow problem. Going to take the tank off and check the screen on the petcock. Sounds far fetched, but would account for all 3 cylinders being affected. Pilot jets, choke, not working properly, but running on main jets when I pull carb cables up using whatever little gas there is in the carbs. Easy to check, raining today though. P.S. plugs were black and sooty after run, except centre plug (slightly lean), the only one I didn't pull the cable on

[shiloh]

If everything else checks out then pull dissasemble and clean all the carbs aswell as the petcock.
If its been sitting varnish and gunk will mess fuel flow and metering..

[robert1]

Thanks for your suggestions. As it turns out, the s series slides are symmetrical opposite and I had them in the wrong carbs. Switched them, cleaned plugs, started and idled as normal one kick. I remember reading of the slides on the forum, but didn't think too much about it, after all groove and pin, has to be right.. Thanks to whoever posted about the carb slides.

[robert1]

Thanks to Johnny o, your tip made my weekend. And thankfully there is a site like this!

[rocket]

Have you done a leak test on the crank ? Sounds like air is passing from cylinder to cylinder or an air issue of some sort ...