Fuel starvation in big whoops


8 replies to this topic
  • CanadianWR450

Posted September 04, 2011 - 11:53 AM

#1

When I get into a bunch of big whoops, and there is a lot of them, my bike will start starving for fuel.
Get off the gas before it completely dies and it will come back, if you don't get off it in time, and it dies, it will fire right back up after a couple of seconds....
Luckily, I'm not in big, fast whoops often.

Any idea's, or anyone know of any fuel bowl mods to fix?

Interestingly enough, it seems to have only started to do it after I re routed the two top carb vent lines to solve the issue where it would stall in water crossings (and it worked :)). Not saying it's related, just an observation.

  • Krannie McKranface

Posted September 04, 2011 - 12:34 PM

#2

If you have the stock gas tank cap one-way vent valve (in the hose), remove it. Otherwise, the only things preventing a full float bowl/fuel delivery are a very low float level, pinched fuel line, partially clogged tank petcock strainer
bad float needle (varnished), or a missing 'froth guard' around the main and pilot jet.

  • CanadianWR450

Posted September 04, 2011 - 03:33 PM

#3

Aftermarket vent cap, and it isn't that, I have the bike duel sported now, and can buzz along on the paved roads no issues at all.
It's ONLY in big whoops, and only when it's a pretty good stretch of them, not just a couple...

This "froth guard" seems like it may be on the right track though, it's not the metal "tube" the jets sit in is it? I don't recall seeing anything else in there that would seem to fit that description.

Low float level could be the culprit, with the gas getting sloshed around, and not picked up in the whoops maybe.

  • Krannie McKranface

Posted September 04, 2011 - 04:14 PM

#4

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  • Krannie McKranface

Posted September 04, 2011 - 04:15 PM

#5

Aftermarket vent cap, and it isn't that, I have the bike duel sported now, and can buzz along on the paved roads no issues at all.
It's ONLY in big whoops, and only when it's a pretty good stretch of them, not just a couple...

This "froth guard" seems like it may be on the right track though, it's not the metal "tube" the jets sit in is it? I don't recall seeing anything else in there that would seem to fit that description.

Low float level could be the culprit, with the gas getting sloshed around, and not picked up in the whoops maybe.


The aftermarket 'vent tip' that goes on the breather hose is a constant problem, but it will sometimes only show up when gas consumption is at it's max (WOT).

  • CanadianWR450

Posted September 05, 2011 - 04:34 AM

#6

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Unless the gas fumes were getting to me, I'm 98% positive that piece is NOT in my carb, so I think we may have found the problem.

I replaced the stock gas cap vent and line because it was cracked, and not working well (sticking and causing a vacuum). I might have had my bike at WOT twice for about 1/2 second each time now...because I was tired, and bumps/hits caused me to twist...lol.
Only issue I have with it so far is that if I really cram the fuel into the tank, go for a short spin fuel will expand/percolate out of the vent.

  • strtdsmallproject

Posted September 05, 2011 - 05:59 AM

#7

I had the same problem with rough hills ended up being the float needle. I think the spring was weak on the needle. It would flood on rough areas. I had the same problem on another one of my bikes i changed the needle right away and no problems at all.

  • strtdsmallproject

Posted September 05, 2011 - 06:00 AM

#8

i think a replacement is like 5-7 bucks on ebay

  • Krannie McKranface

Posted September 05, 2011 - 06:42 AM

#9

I had the same problem with rough hills ended up being the float needle. I think the spring was weak on the needle. It would flood on rough areas. I had the same problem on another one of my bikes i changed the needle right away and no problems at all.


:):worthy::):thumbsup:




 
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