'85 250sx, boggin and dying,,

[estranged]

ran fine when bought a week ago,,ticking in topend tho, hoping just valve clearance,,but started just a touch of elec, start, and ran excellent,

cleaned air box out,,wasnt too bad, few bees and couple other insects in bottom ,,did not clean filter tho, cause can't seem to get foam from around the filter, off the filter, must be aftermarket, and discard only or something,, cleaned the breather tube out and the bowl under the fuel petcock,(both of which were jammed full of junk) changed the oil (not filter tho) used 10w-30,,

went to start it, started fine,, but bog at 0 - 1/4 throttle,,then died,, took alot to start it again, tried choke, gas cap off, air box cover off, and finally started again but bog again,, took for a little drive and after enough screwing with gas cap and choke, started to run right again,,then started it again, in 5th mostly, but sometimes when just puttering around too,, then trouble starting again, took plug out,, tip is black, porcellein is brown, threads have black ring around the tip, dry,

it seems to do this kinda when ever it wants or feels like it , i am gonna try and take fuel filter screen thing out out of gas tank and clean, if not rusted on too bad. also take off carb and clean, (do i HAVE to have new gaskets for carb), maybe see if can get a new air filter, new plug, adjust valves,

do you guys think this is fuel problem or air problem? would the valves needing adustment cause this?,, manual says 10w-40, would using 10w-30 make a difference? just weird cause trike ran great, before i cleaned out all the junk? I know i just need to do what i said im going to do,, but just wanna know if anything else i should check while going through trike, cause i don't have a shop here, and have to travel a ways to use one,

thanks for any suggestions you guys could give me, and sorry for the long winded post, just a noob and gotta learn how to explain better and shorter,,

[estranged]

well, took off tank and found out that it was dirty as hell in there,
so washed it out real good, and then took carb off and cleaned all the jets, which were not actually very dirty,,

anyways it starts excellent, and runs fine for a bit, but still decides to bog, sputter, and little backfires and die sometimes, mostly when letting off throttle and slowing down, then takes a bit to get to started, using choke,,

but then goes again, but soon enough, not even a mile sometimes, does it again,,

my guess is not getting fuel, but why??
tank cleaned, strainer cleaned, fuel screen clean,, carb cleaned,,

Is this maybe the coil getting hot and then when cools starts again??
but would it cool in like 3 mins to start again?
maybe i will get another plug, and next time it does it, quickly hop off pull plug wire and see if spark on new plug?? the plug in it looks fine,, nice tan color??

Please help someone,, suggestions,, ideas,, anything??

[Kerick]

are all the screws and jets where they were...did u count the # of turns in before u took it out?

[estranged]

well manual only said to worry about pilot jet,, so i did count screw turns on it,,it was basically screwed in till seated lightly and 1/4 turn out or so,,

all others were just screwed in ,,as manual said nothing about counting screw turns on them,, all jets were clean, but cleaned anyways,, and float and everything seems fine,,

but it acts the exact same after carb clean as before??

runs fine for a bit then bogs out and dies,, im thinking electrical now,,
just great,, i know nothing about the electrical systems,
can i just use a multimeter to test resistance,, on coil,, and cdi box, and pulse generator,,

i dunno maybe its mechanic time,,

[estranged]

well finally found the problem, (i think), was riding it and after it died,, i decided to quickly pull the fuel line,, (yes, i can't beleive i never did it before either)
and yup,, no fuel,, so i opened the gas cap,, and the fuel came pouring out,,

so my question now is,,
How do i clean the cap vent??
my manual just says check that its clear,, but does not explain it,, i don't understand how?

is it the little pin hole outside the rubber,, or the holes where the notches sticking out,, does not look like the cap comes apart??

[peco250sx]

i had the same problem with my sx those gas caps are a pain and expensive. i tryed to clean it, unjam the on/off valve but nothing worked i even resorted to beating it with a , so i drilled a hole in the top of the gas cap and put a hose on the end to keep junk out, dont bother trying to get a new one they cost like $50+ and they work better with the hose anyways.

[mcdonl]

i had the same problem with my sx those gas caps are a pain and expensive. i tryed to clean it, unjam the on/off valve but nothing worked i even resorted to beating it with a , so i drilled a hole in the top of the gas cap and put a hose on the end to keep junk out, dont bother trying to get a new one they cost like $50+ and they work better with the hose anyways.

Awesome idea. I think I am having the same problem.

[RoadRacer 831]

i had the same problem with my sx those gas caps are a pain and expensive. i tryed to clean it, unjam the on/off valve but nothing worked i even resorted to beating it with a , so i drilled a hole in the top of the gas cap and put a hose on the end to keep junk out, dont bother trying to get a new one they cost like $50+ and they work better with the hose anyways.

What purpose does the On/Off lever serve? My gas cap goes goes on or off the tank with the lever in either position

[hublake]

I am not sure but I think the on/off knob on the gas cap controls the air entering the tank. Leave it on on.

[code200k]

i think the switches stop working after awhile because i can run my bosses 200s either way all day..