Is my carb missing an o'ring?

[tywebb3]

I am having problems with my daughters Raptor 80 with Mikuni carb. The bike will only run when the choke is on.

I have disassembled and dipped the carb and will be putting it back together soon. My question is, is there supposed to be an o'ring on the end of the air idle screw and/or the throttle stop screw? The exploded view in the manual isn't very clear. It looks like the air idle screw doesn't get one and the throttle stop screw does? I don't have an o-ring on either (just a spring and washer) and was thinking I may have an air leak at the throttle stop screw that is causing my troubles? I was hoping this might be the same across many Mikuni carbs and I could get some help here?

[matts27]

The mikuni's I've worked on were for bikes, the pilot jet has an O ring but they used butterfly adjusting screws for idle and the air was through the jet. Best I can tell you is go to cheapcycles.com and go through the stock pdf files for carb parts, they will expand to full screen and you should be able to check. I would assume the air idle would have an O ring though. Good luck, Matt