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Pilot screw help NC30 1989

Posted: Mon Feb 16, 2026 7:34 pm
by Jethro
Having issues with a hanging idle after I adjusted the pilot screws as the bike was running hot. It has an aftermarket tyga exhaust and the pilot screws were set to 1 3/4 turns out. Bike idled and revved fine at 1 3/4 turns. But I went for a run and the bike stalled on idle and the temperature went up to 90°C The thermostat is brand new along with new o rings. So I adjusted the pilots after purchasing 450mm screwdrivers to reach the screws. And now she fires up straight away, but the idle hangs. When I spray the screws with penetrating oil, things improve albeit briefly. I have also checked the carburettor inlet manifold rubbers and they are fine. Im thinking new O rings on the pilot screws and check that the washers are the correct way around. Does anyone know what size the O rings are? And also what size the washers are, in case they are missing. Before I bought the bike, the carbs were supposedly serviced and balanced. But they weren't seated correctly before I removed them. So i don't hold much hope of the screws being complete. I have tried to give as much info as possible. Any advice is gratefully recieved.

Re: Pilot screw help NC30 1989

Posted: Tue Feb 17, 2026 9:19 pm
by magg
Don't understand the issue and your actions. Why adjust the mixture screws because the bike was running hot. Why did the engine temp rise to 90 deg after it stalled. Idle stop screw and mixture screws are used to adjust the idle stability. A hanging idle usually indicates the idle stop screw and mixture screws are simiply misadjusted.