i have an older 250 Trail Boss .. i flipped it and wrecked the throttle cable and my plug was dying out on me too, so i went out and bought the throttle cable and plug and installed them. my electric start is dead so i pulled n pulled my pull chord and it wouldnt start until i gave it sum gas so i set up the adjusting screws on the throttle cable and it ran n idled fine, i drove it for bout 20 or 30 mins and it was still idling fine, shut it off. i came out the next morning and it wouldnt start and i havent touched it, i checked the plug its a lil carbed up already, im not so good with this stuff but is that bad? its gettin gas on it so its still gettin gas, i cleaned out the fuel filter and i've played with my idling and those adjusters and made sure all my electrical was ok and tested the firing and its firing ok, any help at all guys
Thanks

 

I had the same problem with my 250 for awhile.....spark was good, and compression was ok.......I advanced my ignition timing a lil till it idled smooth....now it starts on the first pull

 

ignition timing? .... how'd u set that? please help me out here i'd love it[img]i/expressions/face-icon-small-smile.gif[/img]

 

if anyone at all can help me please do, i have no clue how to set the ignition timing, i didnt know you could please help, i wanna get that thing running to sell

 

Take the carb off and clean it.

 

when i changed the throttle cable i cleaned out the bowl and all inside of it and stuff, its shiny clean thanks tho, anyone know bout the ignition timing?

 

Did you take the jets out and make sure they are clear.The timing rarly if ever gets off.

 

no actually i never cleaned out the pilot jet and main jet, but i did clean out the needle jet and the needle itself but ill do that tomorrow, any other suggestions? i was also thinking coil?

 

Hey, thanks i got the bike going after cleanin the jets but now today i was driving it on the ice and spinning around a lil but i wasnt holdin it right to the boards or anythin and it wasnt running real hot and i spun around and went to hit it and it just bogged and went a lil n bogged then i heard a bunch of metal hitting, i took the head off and the piston looks ok, would you say that i dropped the piston skirt? if so how did i do this, cuz usually isnt it from running too hot?

 

Droppin the skirt is usually done from long high rpm,s. The 400's are known for this but not so much the 250's. The stock piston will eventually do it. If you try to pull start it does the piston move?