I need help with my 1981 special 400. This bike has sat for years until my dad got it running last summer. He said it ran great except the slide was sticking in one of the carbs. Fast forward a year, I want to start riding again so I brought the bike home and cleaned the carbs and got the slides working real smooth. When I put the carbs on and started it up, it idled great. But, every time I even gently try to give it some throttle it dies. Did I miss something when I cleaned the carbs or could something be out of adjustment? Any advice is appreciated.

I need help with my 1981 special 400. This bike has sat for years until my dad got it running last summer. He said it ran great except the slide was sticking in one of the carbs. Fast forward a year, I want to start riding again so I brought the bike home and cleaned the carbs and got the slides working real smooth. When I put the carbs on and started it up, it idled great. But, every time I even gently try to give it some throttle it dies. Did I miss something when I cleaned the carbs or could something be out of adjustment? Any advice is appreciated.

presumably its an xs400!

the carbs need a really good clean, ie strip and all the orifcies clear, use berrymans or seafoam and blow through with air.

another thing to check for once you get it clean is if you spray all around the rubber connecting to the carbs with wd-40 while its running and see if the rpm's spike then

you also know you got an air leak which will make the bike do weird things as well.

I will "reluctantly" try cleaning them again. I have had them apart four times and thought I found every jet and orifice. Can anyone point me to a good diagram that would help me see if I'm missing a passage when cleaning it. I have sprayed carb cleaner through every whole I could find and saw the cleaner spray out into the venturi, so I thoug I was doing pretty good until I started trying to give it throttle.

Thanks for your input.

I will "reluctantly" try cleaning them again. I have had them apart four times and thought I found every jet and orifice. Can anyone point me to a good diagram that would help me see if I'm missing a passage when cleaning it. I have sprayed carb cleaner through every whole I could find and saw the cleaner spray out into the venturi, so I thoug I was doing pretty good until I started trying to give it throttle.

Thanks for your input.

try the float bowl too, there is a passage way there too!

try the float bowl too, there is a passage way there too!

also check the float height and float valve needle, could be fuel starvation, petrol level to low in the carb

It's running! It was the pilot jets. They have those rubber stoppers over them and I had no idea that there was a jet under there until I found a photo on this forum showing arrows pointing to the main and pilot. It runs great from idle to high throttle cruising around the neighborhood on the test run. Thanks for the help. I'm sure I'll be back for more info, now I need to make it road worthy with tires, brakes, blinkers, and headlight among other things.