Rode from the Houston area to Kerrville (about 250mi) a few days ago to ride the 3-sisters in the TX hill country. (AWESOME ride by the way) The weather was mild, about 70 all day. I shut her down when we got to the hotel, checked in, and that's when it happened...

I stood her up off the kickstand and hit the starter. She puked gas so bad that I thought I had a ruptured fuel line. Of course she wouldn't start, so I checked things out and tried again. She puked heavy again. I leaned her back on the stand, cranked a bit more, and no more puking. She fired up after a bit more cranking and ran fine across the parking lot. Shut her sown and cranked her back up a few more times with no problem. Said to myself... "What the hell was that about?!" Rode to dinner later that night... no problem. Rode the 3 sisters the next day (about 230mi of steep hills and tight curves) with no problem. Rode home today, shut her down for a few minutes, and she puked gas again when I tried to start her back up while off the stand. Set her back on the stand and she didn't puke when I cranked her.

I've had the carb puke after shutting down before. I know it's an inherited disease in the R* family. It hasn't happened in a good while and it always happened right after shutting down when hot -- not while cranking and never anywhere near the amount she did to me on these 2 occasions. It was really like gas just pumping out of the air filter as if the float/float needle was hung open, but only when she was standing up straight.

The only thing I've done recently was move the jet needle one clip richer because I felt she was running a bit lean. I have not gone into the bottom of the carb in 6 months or so.

Any ideas?

Yes sounds like a sticking float to me. Try turning the gas off and run it for a few seconds and then shut the bike off. If it cures the problem it very well could be the float sticking. I have never heard of a pump over pumping but any thing is possable.

This has got to be one of the most frustrating things about owning one of these awesome R*'s. I've had this very thing happen under very similar circumstances. Very intermittent and usually at the most inopportune times. Scares the dickens out of me that I might be stranded.

Alas, I've discovered that I can usually hold the throttle full open while cranking and it'll take about 10 turns and start up, cough a bit, the resume running normally.

Been reading a lot of things on here and other sites as to possible causes/solutions, but riding in Texas doesn't offer many days to take it off the road for repairs, so I've endured for now.

However, I'm determined to get into the fuel delivery system, carb, air filter etc. this winter and see if I can't have some kind of positive impact on the situation. My suspicions are that it's running to rich, not possibly not getting enough air, but I can only speculate at this point as I haven't a clue what the jetting is.

I had this problem for all of about 15K miles? Dealer sponsored labor and parts under warranty. No amount of parts will fix the problem, float set everywhere, no luck, new float valves, no luck, they key is to remove parts! Do the lose the fuel pump Mod in tech section, (Install the Suzuki float valve) Do a Pingle Valve for the tank, vent the gas cap and the problem will be over. I had the exact same problem and symptoms and this is only thing that cured mine, I am 17K miles without a puke! (Over the 15 or so K miles puking) Yamaha left us in the cold on this one.

I will say one thing, do it, It's a safety issue, It will stall out at very inopportune times and might get you run over. it's a serious defect.

Mine did that the first few mionths I had when travelling to BIG Bend. It happens twice. Mostly after a fill up and trying to start it to resume the trip. Well, it would refuse to start at first. Then after a couple of cranks it would start pouring out the overflow hose. Like it had a vapor problem, or poor ventilation. After the trip it never did it again, but I was told after yamaha looked at it. I was told that it was possible that it was an altitude issue. I called BS on that, but they couldnt find anything else wrong with it anyway. Same thing with the "other" problems with the carb. I finally replaed that pile of crap carb about a month and a half ago with a new speeedstar unit. I am happier with it and it's quicker!

Is that the HSR 42 mikuni carb I've heard alot about or another?

I was one of the first people on this site to bring up the puking problem. Since then a lot of folks have chimed in. I've gone 5 years with this problem. New pump, re-built carb, multiple settings, everything. All done either by the dealer or myself. There is really no time or place or condition that set mine off so it was virtually impossible to pinpoint the problem. The only constant was the engine was warm(NOT necessarily hot), it would happen when the ignition was turned on, and it would stop when the engine fired up. My conclusion is the pump is the main culprit. It's the only thing that affects the fuel delivery system when the key is turned but the engine has not started. So, as you might have read in a post I have going right now, I have dumped the pump. I have read all sorts of theory's but none of them make much sense since it is a small number of bikes that have this problem.
Unfortunately, with the weather out here right now I won't really be riding that much to truely test it for a while. But I do have a good feeling about it this time, and it looks great!

man, that's a perty bike Bru!

I have encountered this problem a couple of times usually after riding at highway speeds for a while on warm days. Shut it off for a few then go to fire it up again and it spews out the overflow, will be hard to start for a couple of tries then will fire, cough some black smoke and then be fine. Have noticed that on a couple of occasions the fuel pump seemed to run a little longer than normal when I turn on the key. I have had my Roadie for about 3 and a half years putting about 30000 miles on it and it has done this to me about 4 times. Glad to know it is not just my bike that is Bulimic LOL!

Is it possible that since eliminating the fuel pump etc.. seems to cure this that on occasion the fuel between the fuel pumps one way valve and the float bowl heats and expands pushing fuel at higher pressures than the float can hold down and until a bit of running and the pressure balance is restored will continue to do so?

I have had mine do it twice, without isolated circumstance and that was my final thought.

The only fix I could think of without removing the benefit of a fuel pump was to put a 'T' in front of and behind the pump in the fuel lines and run a parallel fuel line with a petcock or a pressure release valve to release pressure back into the line in front of the pump. This seemed a bit complicated, so I now will flip off the petcock and idle the bike about 15-30 seconds without fuel before I shut it off and it hasn't happened again in a month and a half. I have of course had to reach down and "Turn on the fuel stupid!" a couple times after starting up and I have not as yet decided which irritates me more.

If some of us do not want to remove the fuel pump and really hate forgetting to turn on the fuel, it might not be a bad idea to determine a max pressure and see if there is a fuel line sized gasoline safe pressure release valve available at the local industrial supplier.




Max