Won't start when warm?

[Pendulum]

So yesterday I finally had a chance to ride my GS550 after the carb rebuild. Runs pretty good, but needs to be sync'd. However, I stopped for gas and it wouldn't start. I had to sit there for a 1/2 hour and wait for it too cool off. Once it was cool, I got it started on the 3rd or 4th kick. It never did this before the carb rebuild.

[bkrtrsh]

Maybe vapor locked..I would check floats, needle and seat. Did ya try switchin to reserve? Start @ the tank and work your way down...

[cros36]

check your coils

[wilkie]

Could be the vent hole in the gas cap is blocked.If it does it again try lifting the cap to let the air flow and force the gas to move.Failling that if you have CV carbs with a vacuum tap it could be the tap.

[Pendulum]

I was thinking vapor lock. I'm leaning towards something fuel related because it wasn't doing this before I rebuilt the carbs. I gotta get this figured out pretty quick since it gets hotter than hell here in AZ, and a bike that doesn't start when hot is near worthless here in AZ.

I don't think it's the gas cap since it did it right after pumping gas into the tank.

It could be the coils, since they're cheap EMGO. They're almost brand new, though. Like less than 1000 miles on them.

[bkrtrsh]

I was thinking vapor lock. I'm leaning towards something fuel related because it wasn't doing this before I rebuilt the carbs. I gotta get this figured out pretty quick since it gets hotter than hell here in AZ, and a bike that doesn't start when hot is near worthless here in AZ.

I don't think it's the gas cap since it did it right after pumping gas into the tank.

It could be the coils, since they're cheap EMGO. They're almost brand new, though. Like less than 1000 miles on them.

How complete were the rebuild kits? What all did you replace? If there's gas in the bowl at the right level, should run. Lean condition could make the motor run hotter. Leading back to vapor locking.

[Pendulum]

How complete were the rebuild kits? What all did you replace? If there's gas in the bowl at the right level, should run. Lean condition could make the motor run hotter. Leading back to vapor locking.

I tore the carbs all the way down to bare bodies and dipped them in Berrymans for 4 hrs each, then used the stock jets (except for mains), with brand new O Rings. New gaskets from the rebuild kits, with new genuine Mikuni main jets (5 over stock to compensate for straight pipes and pod filters). I know my pilot circuit is lean, so I'll richen that up and see where I'm at.

[bkrtrsh]

Pull the spark plugs, see what color they are. We luv cocoa brown!

[Pendulum]

Pull the spark plugs, see what color they are. We luv cocoa brown!

That was part of my "Gas pump diagnostic" session lol. Looks a wee bit lean, but almost a nice even tan color. I was actually pretty shocked at how well it ran since it was my 1st ride since doing the carbs and pods.

Imagine my disappointment when it wouldn't start back up

[bkrtrsh]

That was part of my "Gas pump diagnostic" session lol. Looks a wee bit lean, but almost a nice even tan color. I was actually pretty shocked at how well it ran since it was my 1st ride since doing the carbs and pods.

Imagine my disappointment when it wouldn't start back up

Been there. You're feelin like the shit, then your bike takes a shit.
Tan's not a bad color, but in AZ more fuel aint a bad thing. Sounds like your doin the right stuff. Tinkering leads to more tinkering. You'll get it..How boring would it be if they ran perfect every time.

[Pendulum]

Been there. You're feelin like the shit, then your bike takes a shit.
Tan's not a bad color, but in AZ more fuel aint a bad thing. Sounds like your doin the right stuff. Tinkering leads to more tinkering. You'll get it..How boring would it be if they ran perfect every time.

haha that's right. I was on my way to a buddys house to use his motorcycle jack to lube my chain and I stopped for gas. Wouldn't start back up. So I called him to let him know I was gonna be a while, and he jumped on his XS650 to come help me out. Calls me about 10 minutes later saying his engine ground bolt came loose and fell off on the highway somewhere. He rigged it up and made it to me, we tinkered on mine a bit and couldn't find any obvious issues. I used one of his plugs and held it against the head to check for spark, and my bike almost started! Hooked the 4th plug wire back up, and she fired right up. Took off towards his place, and a mile out from his house his electrical box fucking fell off! Those XS650s vibrate way too damn much, and he taught himself to weld with that electrical box mount haha.

While we rigged his bike up again, no less than 10 RUBs passed us. Fuck them lol

[bkrtrsh]

So there I am, stroker motor just outa the shop. Lookin for a reason to do some miles. I know, got some brake rotors I need turned. Down to the local shop, drop em off. Go back out to that badass bike with the stroker motor. Ground the battery down to nuthin, aint gonna go. Two mechanics had to come out and push me around he parkin lot till it fired. WOW-How fuckin cool am I?

[Pendulum]

Bringing back this thread since I just got paid and can order parts!

I'm thinking it's got something to do with the really lean pilot circuit. Anyone think that could be the issue?

[MTW]

Does your bike have a vacuum actuated petcock? I had the diaphram in one go bad when it set out for a while without gas on it. It would fill the float bowls because it was leaking past the plunger but it wouldn't open enough to keep the bowls full while running. It would run for about 15 miles and stall due to lack of gas. If it sat for about 10 minutes or so the bowls would fill back up because of the gas trickling through the petcock and I'd be good for another 15 miles. Diagnosing that one was fun! (And by fun I mean it was a fucking bitch.)

[Pendulum]

Does your bike have a vacuum actuated petcock? I had the diaphram in one go bad when it set out for a while without gas on it. It would fill the float bowls because it was leaking past the plunger but it wouldn't open enough to keep the bowls full while running. It would run for about 15 miles and stall due to lack of gas. If it sat for about 10 minutes or so the bowls would fill back up because of the gas trickling through the petcock and I'd be good for another 15 miles. Diagnosing that one was fun! (And by fun I mean it was a fucking bitch.)

It does have a vacuum petcock... I'll test it out tonight. Thanks.