trx300fw high speed shutdown

[Scotts Homerepair]

I have a 1996 trx300fw....  runs great, except if I run it very long 3/4 or WOT it will shut off for 2-3 seconds, then catch its breath and keep going for another 10-15 seconds, then shut off or 2 seconds,, over and over...... I have cleaned the carb, and my gas flow is good... happens whether gas is on.. or is on reserve.... thought it was the rev limiter, but I get told that the rev limiter will not shut the engine down.. just won't go above 6k rpm... really scratching my head on this.. any ideas?..... i can run wot for short bursts.. just not prolonged high speed without the shutdown...

[Frank Angerano]

It may not be a fuel issue. Could be a pick up coil getting hot or an electrical break down where something is getting hot. Or high rpm throwing off the timing of the spark at the pick up coil maybe but that would only happen if something was loose (flywheel) keyway. 

[Scotts Homerepair]

This will happen soon as I leave (cold engine) or if I ride all day beforehand.  Never happens less than 3/4 throttle,,, is why I think its fuel related... fuel means carb,, (cleaned twice)... no change... even thought it could be running super rich, where the fuel flow couldn't keep up... exactly what it acts like.. runs our of gas.. but I have cleaned the tank, even took the line off the carb and watched the tank empty its self via petcock... steady stream the whole time... i dunno.. guess ill just have to live with it... all should be fine unless I get into a police chase, as its illegal to ride on the road here... just aggravating as heck....

[Frank Angerano]

I’m wondering if you have the float set at the proper level. Is it possible that you bent the tab that holds the fill needle in the bowl and maybe prematurely cutting the fuel filling up the bowl to the proper level?  Maybe take a look at that it happens. 

[Frank Angerano]

Take a look at this pic, I added a red arrow pointing to the tab but would only apply if you have the metal tab on your float as some floats are only plastic. It gets bent in any one direction two things will happen the float will push up to soon or not push up far enough resulting in a flooding of the carburetor. Good luck. 

[Scotts Homerepair]

my float is plastic,, no adjustment... if I open my drain screw, it will definatly run out faster than it could use it.. so plenty is getting to the bowl... and usually if its ignition related,,, i should hear some form of misfire or something... this thing runs like a top!.... i have had some issues with my starter valve hanging up... but while i was cleaning the carb,, i sprayed it also, (the valve and the bore) now it works as should...what a puzzle aye?... air, fire, fuel.. ... i know im getting air.... i know im getting fuel to the bowl... clean carb, jets all are open... could a rev limiter malfunction and cause total shutdown of the spark?.. im yet to use the timing light to see if its still has fire when it shuts off... sure im not the first one this has happend to... hope someone could give definite answer...i will be sure to post update if I find it...

[davefrombc]

Even  plastic floats have a  height adjustment  tab.  It  may be set too   low  and the  carb bowl  is not filling to the proper level.  Opening the drain screw  merely tells you the   bowl  is  getting fuel,  not  if it is at the proper level  or  not .

[mcbike57]

It is possible that you might have a blocked or partially blocked vent in your fuel cap. It is also possible that the float bowl vent line or lines is/are stopped up. Worth a look.