Engine Sputter

[TomL]

My 99 I/S started to sputter on the way home from work today as if the tank needed to be switched over to reserve.  Problem is I am only half empty.  I switched it over to "reserve" and it stopped sputtering, then I switched over to "ON" and it seemed to clear up.  Any ideas or suggestions?  Thanks in advance.

Tom (treefarmer)

[sandy]

That happened to me and it's been posted before by others. I replaced the whole petcock but you can probably replace the cover set and it'll fix it. That's the vacuum operated diaphragm repair kit for the petcock. A Pingle valve replacement works too but it'll be BIG $$$$.

[John U.]

Those symptoms sound like the petcock screen may be partiallly clogged. In reserve there would be more preasure to increase the fuel flow. Why it cleared up when you returned to the run position is a mystery to me.
The petcock diaphragm can be a source of trouble as can the vacume tube to the petcock' These things usually become a problem at full throttle, when the vacume is not sufficient to maintain enough fuel flow.
When you have this problem try stopping and sloshing the fuel around, then run it hard or at high speed. If the problem disappears then returns after a while it may be a clogged screen.
Sorry this isn't more definite.
Let us know what you find.

[TomL]

Thanks John and Sandy.  This is the second tank full since I brought it out of winter storage.  Stored it with a full tank of gas with seafoam added to it.  The first tank full gave me no problems.  I did add an in-line filter before I put her away for the winter.  Hoses all look good.  Could it be bad gas?  I did think it being a petcock problem also.  Those pieces of #$@!.

Tom

[3W-lonerider]

same exact thing happened to me a few years ago..engine would act like it was running out of fuel..i'd switch to reserve then back to on and it would be fine..this went on for about 2 weeks. same thing everytime i'd go for a ride. it was the start of bigger problems..i was out in the middle of nowhere going up a mountain having to drop gears because the engine had no power.. half way up the mountain the bike died. managed to get it turned around and coasted back down the mountain. it fired up at the bottom as if nothing ever happened. took it home and it ran fine. only problem i had was the bike had no power in the higher gears. you could give it a handfull and it would just gradually pick up and go. once home i took the fuel tank off and tore the petcock apart. i found the diaphram was split in 2 places. installed a new cover set and everything was fine.