HELP!!!!

My gess is your bilding up to much back pressure if it is a EXUP. Maby give it some revs at the lights.

 

3 things that I would check (in order) are:

EXUP Adjustment (if it has one).
Blockage of the Fuel Tank Vent.
Float Bowl Heights/Emulsion Tubes.

 

I'm with the exup as well on this one - that is what used to happen to me. Fix: I had the exup adjusted so it was slightly open all the time, and while at lights i would hold the clutch and rev the bike to about 8000 for a few seconds the odd time (to release the pressure).

This shouldn't happen at all though when the exup is properly adjusted. Usually this is a sign of other minor problems (i.e. floats, blocked vent, or perhaps clogged fuel filter). It could even be if the air filter is too clogged / old.

 

lol this problem is SO common on these bikes... why??

the EXUP if not ajusted properly will "suficate" the engine at low RPM.. simply the bike will run rich and fowl up the plugs!!

so a. clean the EXUP b. ajust it c. change the plugs

 

That was my third option... Carb stuff...

Do a complete cleaning, check the float heights, and then resync. the carbs.

 

The EXACT thing happens to my 88 2kr (sans exup). Only, it happens just after i take off for the first time after start, or maybe again at the first set of lights/stop sign.

What i do is rev to 5k every 10 seconds or so at a red light. You may look like you're trying to look tough, but at least it'll go well. Giving heaps of revs before you let the clutch out also helps, which isn't a problem for a 250.

Also, where is the fuel tank vent, and the emulsion tubes?

Thanks

 

The tank vent is located on the underside of the fuel cap. Open it up and you'll see a little hole on the underside. That is the vent to the outside. It is there to equalize the pressure difference from the carbs/fuel pump using fuel.

Emulsion Tubes are located inside the carbs and is what the needle slides up and down in. Thay are also known as needle jets. Dissembly of the carbs is required.