I am running stock carb. Second one because of this:

When I am in "the train" heading into the woods, it is usually very dusty. So dusty you can only see the guy in front of you, barely. At this point we are WOT. She pulls strong and everything seems to be okay, then she boggs and boggs and spits and farts. I have to pull over and watch the top pack leave while the rest of the pack is coming and finally... going. Then, I am by myself. Fumbling with the choke. I finally get it wide open and also the throttle and hit the start button. After a second of this, whatever was in the carb is now out the pipe and I can go.
That happens only during first 200 yards. Never any time else and runs perfect afterwards.
Only when wide open in the dusty convoy. Never anytime else. Wide open or not.
The vent tubes on the sides of the carb going up into the frame are just to keep pressure equal, right? They don't actually suck, do they? Could I be getting something in through there? I have another new fuel filter between the petcock and carb. My plugs look picture perfect.
Any help would be good help.
Someone said I needed to put little filters on those ends?
This next race has awesome trophies and I want one bad. I just hope I can get this resolved. One way would to be to make sure to get the holeshot!

 

I would start with the filters - but also, is there ANY way you can duplicate the situation? If you can duplicate the situation in a non-race situation and then fix it that will allow you to operate correctly during the race. The last thing you want to do is try and figure out how to fix something during an actual race. Try the filters, but most of all (before you try them) see if you can duplicate the problem - if you can duplicate the problem on command then you can easily figure out if you have fixed it; which is the goal.

 

If its not your filters letting something in you might want to buy a can of hot shot starting fluid. spray it on your snorkal and see if the motor revs higher. you can spray some around your intake to make sure it has a good deal there also. if you spray it there make sure its just after you fire it up . dont give that motor a chance to heat up this stuff is highly flamable. checking these things first with the hot shot could narrow it down to where its coming in at. If these bombs had a reverse you could get it some powdererd dirt and back up as fast as you could so it would duplicate the dusting in the train. The fluid trick comes out of okie mechanics 101 so be careful, real careful.

 

Check the vent tube on your gas tank. They get pinched and create a vacume and will not let fuel to the carb.

DuneDevil

 

LOL!
I asked my friends to get in front of me and fishtail and everything to recreate the problem. The problem with that is I blow them away just when the dust gets good?? I am coming on so strong I will just pass if I keep going WOT.
Okay, I think they are a little scared and don't hold it down like the top riders.
I am off to work and will beat my head agaist the wall some more. Maybe I will jarr an idea loose.

 

this was my first thought as well. you could also loosen the gas cap for a second when it happens again. if it clears up, vent tube pinched/plugged.

 

I thought it might be that, too. But no. That darn thing is about a mile long.

 

I would suspect the vent tubes on the carb. I would put little filters on them or bring them together and Y them into a single filter, can't hurt....

 

Thats what I thought you dirty rotten scoundrel! Then someone here pointed out that they aren't really vent tubes but rather pressure equalizer?? They swear there is no suction from them.
He then said "well they are breathers" I took a breath and said "I just breathed. First in, then out." He was stumped. I am going to have to at least try the t to filter trick and see what happens, I guess.
I just wonder why it doesn't happen to the other guys on the other machines?
And no it's not because my DS is a piece of $hit!

 

It really sound to me like you are sucking your Bowl dry under hard long acceleration and running out of gas. After you sit a half a minute the bowl fills back up, then you are good to go. The rest of the race you probably are not at WOT long enough to suck the bowl dry again. Thier is no need to have an additional in-line fuel filter. Their is a filter screen attached the the stock petcock. You are probably slowing the flow to the carb too much, thus runninf out of fuel.



ALSO make sure your Float level in your carb is correct, your bowl may only be filling up half way.





Bigger.