Fuel selector valve: Inherently bad design or just a maintenance thing?

[CentralCoaster]

I just got my '99 GSE last week and it seems to have the typical fuel valve issues.  In "ON" position, I've had it stumble past 4K rpm and die at some busy intersections.  Turning it to prime seems to correct it.  I searched the forum and found all sorts of alternate solutions but there doesn't seem to be a consensus on the best fix.

Are these things crap from the factory, or just after 10 years of getting gummed up?  Would it be a waste of time to replace it with a new part?  Are manual valves commonplace on the newer bikes, or do they use some sort of electrical or vacuum safety too?

I'm not looking to JB weld anything or jury rig it to save a buck, I just want it to work correctly and not have to push my bike through any more busy intersections.

I'll take it apart tonight and see if its serviceable.

[gsJack]

I put over 80k miles on my 97 GS without any fuel valve problems and then it sat unused for a couple years until my son started using it and he had problems like you describe.  He fixed it with a new stock fuel valve.  There is a rubber diaphram in the valve that shuts off fuel flow when engine is turned off and that probably leaks air a bit when it gets old and then doesn't open all the way.  Old fouled spark plugs can start cutting out about that speed too, a new set is cheap.

[beRto]

My experiences are similar to those of gsJack; I was having fuel starvation problems on my 1995. I replaced the petcock with another stock version and no problems since!


edit: fixed typo

[scottpA_GS]

I replaced mine w/ stock as well... I also needed a carb cleaning. Cant hurt to do both 

[The Buddha]

Its both. Poor maintenance wont hurt much if its a better design. BTW in the world of petcocks, the worst IMHO is kawi, suzuki is a distant second, Yammies are possibly third, none of mine have had nothing but a fuel pump though, and seca has a vacuum pump. Honda is the best, and their design is so unique that its not even worth comparing. Also the honda ones are the easiest to transplant on another tank. Honda's I have had though dont have a real prime position. My nighthawk has off, on and res, and its vacuum operated. Odd, no vacuum = off isn't it.
Cool.
Srinath.

[Ski1215]

Mine also runs better on prime than it does in the 'On' position. After reading this I guess its time for a stock replacement.

[trumpetguy]

Maybe I just had not noticed, but I don't recall reading (until this thread) that some folks have had success replacing their poorly functioning valves with new OEM replacements.

If you have replaced yours, please reply in this thread and report the results.  Did it completely solve the problem?  If so, I'd happily spend the $$$.  If it's still iffy, I'll continue to flip the valve to prime whenever the issue comes up (mine isn't an all-the-time problem).

[rnicholas]

i purchased an 89 and had some starvation issues.  Bike didn't sit for long periods of time, but it does have 21,000 on it.  A friend of mine works at the suzuki dealer in the parts/maint dept and he suggested a new petcock.  I was going to mod it to a non-vacuum system but he assured me a new stock one would solve issues.

New stock petcock solved it all.  Now I don't ever have to run in prime.  I find that on works great at idle, 25 and 85 on the hwy. 

If you replace the petcock, I suggest you spend the little extra and replace the fuel and vacuum lines too.  It's pretty cheap and you will be positive your system is in order with no leaks, etc.

[frankieG]

I went thru the same thing on my 89.  Turns out it was a vacuum. Thing.  Make sure the filler cap air holes are clear.  Easiest way to check is to open and close the cap when the bike is running rough.  If it runs smooth after you do that it is the cap