Been reading the comments on Carb Puking.... My 04 has done it a couple of times when very hot..... talked with a Harley Mechanic yesterday... he said the Harly's are bad about it also.... so I guess it ain't just a Yamahammer problem.
tt

It was pretty common with all the air cooled carb'd bikes. EFI has resolved a lot of that.

Have you checked your carb float level??

Mine does it really bad, from a small puke to a throw up! I'm working on the problem. Seems to be related to heat. So far I have drilled a hole in the air cleaner back where the tube runs down, well now the tube is gone and a hose runs from the vent down where the tube used to be through the plastic where I drilled a hole and around the backside of the pushrod tube and under the bike.

This only gets the gas to the ground instead of on the engine, it still pukes.

No one has the answer. It is related to heat.
So far I have had the
*Carb wrapped in heat shielding tape, No workie
*Vent tube run up to tree and down to ground. (Just flooded out)
*Various float bowl settings 2mm 5mm so on, no difference.
*3 new needle and seats, no difference.
*Re Jetted 5 times, all ran fine, still puked.
*Heat shielded fuel line from tank to carb.
*Practice shutting fuel off way before shutting bike off.
* Begged people here to solve my problem. No work either.

I have Ben Herr Manifold, so I may retain more heat. But I do notice people who do pump relocate or lose the pump seem to have less of the problem. And an aftermarket air cleaner also seems to relieve the problem, most likely because you get better air circulation back there and thus less heat. Same for fuel pump mods, the absence of the fuel pump allows more air to the area and less heat.

What happens is (They say) after shutdown gas boils in the bowl, why it comes out the vent hole I can't figure out as it's like way far from the bowl. But I am certain that's where it pukes from.
One day I'll figure it out and I may not tell, because it's top secret you see, I know people here know, they just ain't telling.

MS1700 wrote:
One day I'll figure it out and I may not tell, because it's top secret you see, I know people here know, they just ain't telling.

MS1700, if you figure out the Roadie carb puking problem, you'll be on the same level as the guy's that invented WD40, post-it notes, and Captain Crunch!!!!!

I first noticed my bike puking after I used Sea Foam in it over the winter. I remember smelling gas and hearing the fuel pump click a few times when I went to restart it when it was hot last summer but I never looked down to see what was happening. I wonder how many people don't realize that their bike is doing it! I have a buddy with a Silverado that swears his doesn't do it. He has an aftermarket air cleaner on his, so the stock airbox may very well be the problem. I too am determined to figure this thing out! It hasn't even gotten hot here yet and my bike has done it at least twice. Just to be sure we're all on the same page, mine does it when I go to restart it when the engine is hot.

My roadie pukes too, especially when it is scorching hot. Talked to a yamaha mechanic at the local dealership and he told me something I had not heard before. He said the reason for the puking was the gas now has additives that "boil" at a lower temperature and when the bike has been run and it is very hot it will boil and puke out of the carb.
Don't know if that is what's happening or not but it was something different to listen too.

Keep it upright,
Revit

Has anyone tried disconnecting the carb heater to see if it helps?

Not to age myself here, but, a lot of you guys will remember like I do, that cars from the 60's and 70's would 'vapor lock'. The fuel lines were too close to the exhaust system and had no insulation, so the gas inside them would boil.

I believe we have a similar problem with our 'carb puking'. In the stock setup, the fuel lines run between the jugs where all the heat is. The lines are insulation wrapped, but, it's minimal. They epecially heat up when the bike is hot and you stop for awhile so that there is no air flow in there at all. The fuel in the lines is no longer moving, so it heats up, expands and has to go somewhere. It can't go back through the pump, so the only other place it can escape to is the carb, which of course then spills out the overflow and all over your bike.

I think MS1700 is onto something with regard to the stock fuel pump and air cleaner blocking the airflow in between the jugs. That further bolsters my theory about why they do this. I moved my fuel pump for looks, but, it significantly reduced the puking. The fuel lines no longer run directly between the jugs and although I still get some minor gas smell sometimes, I don't have the gas spilling all over the place.

Just my .02. Ratl.

I am a lowely TV repairman, however many of the new flat panel TV's have internal fans to keep air moving. Wonder if it would be possible to install a small fan between the Jugs?
tt
PS... what does Yamaha say about this???