High Smoke, Dies off choke. vacuum leak?

[Max Vador]

so i gave my 95 750 to a buddy and he just replaced the starter. he had to pull the tank, airbox, carbs, and oil line off the pump so that's what we're dealing with in possibilities.

after replacing the starter and putting the bike back together, it will only start on full choke and is smoking a lot. once he closes the choke the bike dies. it sounds to me like either the airbox to carb seal is leaking, or he lost a hose on the carbs themselves. any experience with this?

SOLVED: Vacuum to petcock was blocked/pinched

[92xjunker]

Dirt in the carbs, vac leak would be high idle. Unless it's a major air leak.

[Max Vador]

that's why i suspected the airbox boots. it's easy to put them on wrong and would be a big leak

[92xjunker]

Air box leak won't prevent idling.

[shpielers]

Where's the smoke coming from?
If it's from the exhaust and it's black that's a sign of running rich.

[loneraider]

This sounds like a Do It Yourself fix it job.
I would back track everything except the starter and look for anything
out of place such as carb boots, kinked fuel lines, throttle & choke cable.
If not there then pull the carbs/

[Max Vador]

Where's the smoke coming from?
If it's from the exhaust and it's black that's a sign of running rich.

it's from the exhaust. not sure if white or black. i'll be going over there tonight to check it out and we'll pull the tank again

[Tippon]

Maybe daft, but easy to miss, but my '98 600 does this when the engine's cold. The smoke isn't every time though. What happens if he lets it idle on the choke for a few minutes?

[Max Vador]

Maybe daft, but easy to miss, but my '98 600 does this when the engine's cold. The smoke isn't every time though. What happens if he lets it idle on the choke for a few minutes?

even after warming up it dies once you take the choke off. it's faint white smoke like any choked start. i'm suspecting pinched vacuum line at this point. still haven't taken it apart

[shpielers]

Check for pinched fuel lines too when you get a chance.

[Max Vador]

Check for pinched fuel lines too when you get a chance.

definitely. i know that line that runs to carb #4 that sits right under the tank has a tendency to get pinched off so that's gonna be the first one i look at.

[Max Vador]

as an update

cleaned out the carbs. had some carbon build up and one of the fuel lines was kinked under the tank.

NOW: Bike runs perfectly in the garage with the tank propped up. once we put the tank down and try to ride it it chokes out trying to go into gear then eventually runs out of fuel and won't start again. none of the lines are pinching when dropping the tank. checked multiple times.

[shpielers]

Petcock working correctly? Might need a rebuild.

[Max Vador]

petcock doesn't leak when the tank is removed. flows on prime off the bike.

it gets fuel when on the bike. it just doesn't want to keep fuel flowing when we try moving it.

like it absolutely HAS to be a fuel line getting pinched when we bolt the tank back down....but it's not

[shpielers]

Did you apply vacuum and make sure the petcock flows just as freely in "on" or "res"?

Had an issue with mine last summer that sounds kinda similar. Switching to prime the bike ran fine. In the other 2 positions, it'd starve for fuel and shut off. No bueno when you're on the highway in rush hour traffic