Yes you need a good high flow filter to go pumpless. Went pumpless a couple of weeks ago and removed the pump, swapped float valve and added Pingle hi Flow cleanable and reusable Gas In Line filter. Problem I ran into was I used the same filter I had on it before (Maxair had a delay in my Pingle filter shipping) and bike would run great for about 1-2 minutes then it would starve out for fuel(could also be how I was getting on the throttle). Swapped out fuel filter when Pingle one came in and works like a champ. I ran my fuel line from the petcock over the top motor mount below the frame and then down between the cylinders above the manifold and attached to the carb.
I did not vent the gas cap (many different view points on this) and I am not saying I NEVER will just trying to see what works. Want to get a flush mounted gas cap and testing to see if I need the vented or non-vented. I also do not have the Pingle high flow fuel petcock but that is more of a money issue right now. Want to get it someday just can't right now.

Will have to look at how MS1700 has his set up might be a better route.

Scotto wrote:
Mine will puke all the time if I dont shut off the fuel petcock prior to shutting her down.

Exactly correct for me too! I just turn off the fuel and let it burn some out of the bowl and have not had a puddle of gas since

Smittnator wrote:
Yes you need a good high flow filter to go pumpless. Went pumpless a couple of weeks ago and removed the pump, swapped float valve and added Pingle hi Flow cleanable and reusable Gas In Line filter. Problem I ran into was I used the same filter I had on it before (Maxair had a delay in my Pingle filter shipping) and bike would run great for about 1-2 minutes then it would starve out for fuel(could also be how I was getting on the throttle). Swapped out fuel filter when Pingle one came in and works like a champ. I ran my fuel line from the petcock over the top motor mount below the frame and then down between the cylinders above the manifold and attached to the carb.
I did not vent the gas cap (many different view points on this) and I am not saying I NEVER will just trying to see what works. Want to get a flush mounted gas cap and testing to see if I need the vented or non-vented. I also do not have the Pingle high flow fuel petcock but that is more of a money issue right now. Want to get it someday just can't right now.

Will have to look at how MS1700 has his set up might be a better route.

I think the fuel line routing is an issue, you don't want any upward curve to it. I have the 42hsr carb, and was told to route fuel line over manifold under engine stay, I also run with no fuel filter, was told that between the screen on the petcock and the carb inlet screen would be enough. over 2 yrs and never had a dirt clog the carb. as far as pingel, don't need it, stock flows plenty, look for yourself, attach a hose to it into a container and you'll see it flows really fast. if you go with with flush cap, get vented, venting is more critical with carb mod ya did vs 42hsr gravity feed, reason being the valve swap is still kind of on the cusp of being too small, the 42 valve is a 4.2, so as you can see that is huge to what the mod is, also critical is float level, in most it needs to be slightly higher than the mating surface, 1, 2mm as well, also too high it will consume more fuel since vacuum will draw it thru carb ckts too fast as well. And I know of a few that could never get it to run right at high speed and went back to pump. I tried to get some help from Lee (Mikuni head tech) for you guys to see if the 42 valve would fit in stock carb, he did not know, he mentioned to get in touch with Patrick racing, and they might know, I never did tho. any way, hope this helps some

Tusler wrote:

Exactly correct for me too! I just turn off the fuel and let it burn some out of the bowl and have not had a puddle of gas since

Thing is, you still have a problem, shutting the petcock only resolves the symptom does nothing to resolve the problem.

I've run 2 different carb, even in triple digit temps and stuck in traffic for 45min at a crawl, never turned the bike off, didn't pull over, just crawled along with traffic, no puking, no clutch over heating either. An I never have had to shut the petcock, unless removing tank from bike

My scoot has puked since it was fairly new. Not consistent, but messy when it does. Perhaps the most critical thing to check is the float level, and that your tank vent is clear. Since adjusting mine about 6 months ago I have only had one puking occurrence. I still routinely shut off my fuel when I stop and turn it on after the engine starts. This is as much out of practice of many years as from puking. All the motorcyles I owned previous to the Roadie were gravity flow systems and if a float stayed open you could flood your crankcase with gas.

OK, since I've removed the little screen at the carb inlet, I may have to get a Hi-Flow filter to replace the Auto Zone special that I picked up.

If the Hi-Flow filter doesn't completely resolve the issue then I guess the next step is routing the fuel line below the manifold. I'm going to stick w/ the 5/16" black fuel line for now until I get it all resolved then I'll see about some clear fiber reinforced.

Thanks for the input!

I've tried shutting the fuel off prior to stopping but still had an incident with puking last night. This time I got to see it in action for the first time. It belches out with a good deal of force. I can't believe Yamaha put something on the market with a major safety issue like this. I did a Google search on fuel leaking Yamaha Roadstars last night and was amazed at what I found...and that's not just in the RSC. A site called allworldauto, has several posts with similar problems. One even resulted in a fire that damaged the bike but fortunately nobody was hurt. Others like mine started after a few thousand miles and all seems to fall on deaf ears at Yamaha.

I'm to the point that I don't want to ride this machine and don't feel that it's safe...not to mention having my garage wreak of gasoline every time I park it. Has anybody called or contacted any federal agency with this problem or Yamaha directly? From all that I've read so far, it is evident that Yamaha doesn't have a solution to this problem and I'm still not understanding how getting rid of the pump fixes this. Last night my petcock was off, engine off, and it puked gas. In my mind, it shouldn't matter how the fuel got into the carb bowl, gravity or pressured by a pump, it appears that if the bowl is full the potential to belch out fuel is still there.

My dealer is a good friend of mine and I'm going to him today to demand some kind of corrective action. I will keep you posted on what I find.

It is a frustrating problem and there are numerous strings on this site and the Delphi forum with several suggested fixes. There does not seem to be any one fix that gets it corrected. The issue is often linked to heat, although mine has puked on cool days too, so check you fuel line routing to make sure it is not in direct contact with a cylinder head. Check your tank venting, the vent tube that exits on the upper right side under the instrument cluster can get kinked and cause pressure build up in the tank. The highest probability for this issue is the float level in the carb. It needs to be properly set, check the tech articles for guidance. Finally you may have a pressure sensor issue in the fuel pump that is not functioning properly and will need to be replaced, or set up to run pumpless. Finally there is one theory that it is seasonal gasoline "winter gas" that is the cause. If you are concerned about safety attach a hose to the over flow and run it to the ground to insure gas does not go on the hot engine. The gas smell after shut down is usually a good indicator of either incorrect float level, or a cracked TPS cover. I think I have given you a long list of things to check and or adjust. Let us all know if you find out something new.
Just to add this is fairly common with almost all carb'd large V Twin engines. I have seen several Harley's puke on a hot day. It is hard not to super heat the gas in a carb positioned between two big hot jugs. Hope you find the fix, I have personally learned to live with it pretty well and just accept that this is my scoots way of marking her turf

A properly adjusted float will stop the carb puking... if ya go over to the Road Star All Stars on delphi, click on their webpage, it tells ya how to adjust it properly... this will give you optimum gas mileage and stop the carb puking... I adjusted mine per these instructions, and I have not had it puke on me since... and for that just in case moment, if it ever decided to do it again, I ran vacuum line from the place on the carb where it pukes from, down to the bottom of the bike... this way it wont get gas all over the engine and possibly the exhaust again... just my thoughts...

Thanks to all for the excellent recommendations. I just spoke with my local dealer and he is calling a service rep in to take a look at it unless he can advise them on what action to take. They had never heard of the problem before but I don't think they have moved too many Roadstars through their dealership either. I tend to agree that the float level may come into play but still puzzled as to why it just started doing it.

As anticipated, the RSC has been a big support. This is the fist place I went when it happened the first time and it didn't take long to find some info on the problem. Hopefully I will get this annoying problem corrected either by Yamaha service or myself and let you know if gets resolved.