So i have this 1986 yamaha radian that i got to fix up. and i can't seem to figure out why it isnt running.

now here's the symptoms. the battary was kinda dead, and the bike wouldn't turn over. charged the battary, with one of those plug in things, and it turns over, runs for about 20 secons, and then sputters and dies. now i've been able to keep it running for about a while with that spray stuff you put in the air intake, which makes me think that it could not be getting gas. if i leave the petcock on prime long enough, the carbs fill up with gas and it starts leacking from the over flow hoses, so gas is getting into the carbs, and i dont see how it can be there and be starved.

so as you can tell i have this huge dilemma, any input would be swell :)

See if there's a vacuum line going from the engine to the petcock. Lots of bikes have vac. operated petcocks so they don't flood if you forget to close the petcock and have either sunk float or some crap on a float valve seat.

Quoted: So i have this 1986 yamaha radian that i got to fix up. and i can't seem to figure out why it isnt running. now here's the symptoms. the battary was kinda dead, and the bike wouldn't turn over. charged the battary, with one of those plug in things, and it turns over, runs for about 20 secons, and then sputters and dies. now i've been able to keep it running for about a while with that spray stuff you put in the air intake, which makes me think that it could not be getting gas. if i leave the petcock on prime long enough, the carbs fill up with gas and it starts leacking from the over flow hoses, so gas is getting into the carbs, and i dont see how it can be there and be starved. so as you can tell i have this huge dilemma, any input would be swell :)

Petcock -clogged ...fuel filter -clogged ....pilot jet/s -clogged .....in that order of elimination.............................leaking from overflow hoses=set the float level and clean the needle/s and seat/s

Sounds like a stuck float or two, and plugged jets. You can do it yourself, or just take the rack of carbs to a shop and have them cleaned.

Good luck with the Radian, they were really good all around bikes in their day.

also, esp on older Yamaha's, the intake manifolds tend to crack and you get a HUGE vacuum leak and it won't run worth a dang.
I agree with the other guys though, try those things first, vacuum petcock, plugged jets or a stuck float.

Brian

You need to remove the carb/s, disassemble and clean. They need a good ultrasonic cleaning, or at least a dunk tank to soak in.