I’ve been trying to get help from the suzuki gs forums but haven’t got much responses. I’m hoping some of you might be able to assist with this stupid idle problem.
1980 Suzuki GSX400 with twin Mikuni BS34SS
Here’s what’s happening:
• Idle at 500 RPM: The bike idles fine, but after giving it throttle and the idle comes back down, it stalls.
• Idle at 900-1200 RPM: If I touch the throttle, the RPMs stay high, around 2000-3000 RPM.
What I’ve Tried:
• Unhooked the throttle cable
- Float height set to 22.4mm
• Re-centered the butterfly valves/plates. (Pushing on the throttle shaft drops the idle.)
• Adjusted the pilot screws, but they don’t seem to affect the idle.
• Checked the throttle shafts—no excessive play.
• Replaced the intake O-ring and choke plunger.
• Diaphragm is good, and the slides come down smoothly.
• Synced the carbs.
• Replaced the outer seals and inner seals on throttle shaft. They initially leaked, but after replacement, they stopped. However, spraying carb cleaner on them now stalls the bike.
• Spraying carb cleaner on the throttle shaft for 5 seconds causes the bike to quit.
• Changed all the carb O-rings.
• Throttle shaft Spring tension is good, and the butterfly valve closes properly.
• The exhaust gurgles and backfires when RPMs come down whether the pilot screw is at 1 turn or 4 turns out
I’ve been working on this bike for 3 months and i’m losing my mind. Any advice would be awesome.
1980 Suzuki GSX400 with twin Mikuni BS34SS
Here’s what’s happening:
• Idle at 500 RPM: The bike idles fine, but after giving it throttle and the idle comes back down, it stalls.
• Idle at 900-1200 RPM: If I touch the throttle, the RPMs stay high, around 2000-3000 RPM.
What I’ve Tried:
• Unhooked the throttle cable
- Float height set to 22.4mm
• Re-centered the butterfly valves/plates. (Pushing on the throttle shaft drops the idle.)
• Adjusted the pilot screws, but they don’t seem to affect the idle.
• Checked the throttle shafts—no excessive play.
• Replaced the intake O-ring and choke plunger.
• Diaphragm is good, and the slides come down smoothly.
• Synced the carbs.
• Replaced the outer seals and inner seals on throttle shaft. They initially leaked, but after replacement, they stopped. However, spraying carb cleaner on them now stalls the bike.
• Spraying carb cleaner on the throttle shaft for 5 seconds causes the bike to quit.
• Changed all the carb O-rings.
• Throttle shaft Spring tension is good, and the butterfly valve closes properly.
• The exhaust gurgles and backfires when RPMs come down whether the pilot screw is at 1 turn or 4 turns out
I’ve been working on this bike for 3 months and i’m losing my mind. Any advice would be awesome.
