Rejetting a carb?

[1987atc200x]

I know its simple but I have no idea how and my reason for rejetting the bike is because its backfiring and from what I can tell running alittle rich......So how do you do it.....

[1987atc200x]

By the way its a 1987 atc200x

[Rustytinhorn]

What octane gas are you running?
I'd read this thread: http://www.3wheelerworldforums.com/showthread.php?t=55086 If you are wanting to know how to take the carb apart and whatnot, the best place to look would be in the repair manual.
Sorry, hope that helped some.

[rally4x4racer]

if you have ever entertained running an open filter - now is the time. if you open up your intake a little you may hit it without jetting.

[RedRider_AK]

Maybe it's time to change the filter and purge the spark arrestor of carbon buildup...

[1987atc200x]

Will I have a brand new uni filter and I put some regular unleaded in it.....Its weird because it ran real good for like 2 weeks and then all of a sudden it started running real shitty for a day then it just got better today after I put some more gas in it which was also regular. All it does now is if you rev it up it shoots out a 4 inch flame out of exhaust after it back fires.....Another thing that makes me wonder is why I didnt even need the choke to start the bike when its cold......And when I put the choke on it just gets flooded.....So there is another reason I think its running to rich....Any opinions?

[Rustytinhorn]

I wonder if you have a sticky exhaust valve.
Also the reason I asked on the gas is because the higher octane gas you use, the longer burn time. I know if I use high octane in my 200erd's they will backfire, especially when engine braking, becuase of the extended burn time.
How long have you owned and ridden the bike? If it been a long time, then the jetting shouldn't just crap out like that unless a jet fell out.

[1987atc200x]

Well its only been about 2 weeks and it was a used motor i got off ebay.....It had about 40 hours on it according to them and it seems to be the truth because it is a extremely tight motor with absolutely no wear as i can tell....The carburator came with the old blown engine that i purchased with the bike....It supposely has a honda powerup kit but i'm not to sure about that.....The jetting has been weird with this bike since i first started it......The choke never has to be used no matter what.....And if u try to use the choke out of curosity it will flood the carb and wont start for atleast 6 cranks without using the choke.....So I just think the jetting was never right and I need to straighten this out,,,,Any Ideas? Would something as simple as cleaning my airfilter and possibly opening my breather help.....I just dont understand why it would run like a champ then start running like *Edited**Edited**Edited**Edited*....then go back to running good with a back fire here and there......HELP?

[1987atc200x]

Also it has a crappy Cobra Exhaust that sounds raspier that its worth....LOL.....I sat here thinking and I really have came to no conclusion..LOL...I think the jetting is right because its starts with every kick even when its cold and when I rode it today it wasn't to bad at all when it came to opening it up down a straight away....It never lost power like it did that day and it ran like a champ except for the ocassional back fire while engine braking .....Or if I rev it up in neutral a few times it will back fire....It never ran like that before though, so i would like to know whats wrong.....also if it is jetting what would it most likely be....Would it be rich or to lean.... By the way I own a Crf230f and it will back fire like u wont believe......I mean it will do it constantly when you let off the gas and its all stock.....Plus it runs extremely lean because coming out of factory they make them run lean for some reason.......SO I'm sort of leaning towards it running to lean.....Man I dont know lol.....Its killing me...does anyone have any ideas....By the way I remebered something that i did....I Started the bike with no muffler for a few seconds to try hearing my white bro exhaust that I was goin to try to make fit by just placeing it over the pipe.....(U know, Being Bored and Trying TO Find Some Thing To-Do in the Shop....LOL) will anyway the motor running like that happened right after I did that......SO COuld I have Screwed SOmething Up....i cant believe reving it up a few times could have hurt it but its possible right.....Anway Need Help and if anyone could give me a clue for why it runs like that i would be happy to hear it...

[1987atc200x]

By the way i checked the oil today after I rode it and it is absolutely fine and at the same level it was 2 weeks ago so I'm doing good on that.....Compression feels good and like it should feel....So evrything checks.....Oh the filter is alittle dusty but not bad at all......I'm not running a fuel filter tho....could I have gotten something in the carb and its starting to work its way through.....It seems like the more I ride it at this point the better it gets so this is a thought.......Oh it idles fine also....

[honda_atc200es]

try a smaller pilot jet, open up your air
box lid and adjust your fuel air mixture, its all about trail and error there is no set specification, and usually no explination for jetting problems, it definately seems like your running rich, run the bike at wot for 10 seconds or so, turn off the bike and check the plug, black is rich, gray is lean, tan is perfect, but the plug chop isnt always 100 percent right. try those suggestions.

[Dirtcrasher]

EVERYONE, especially with a metal tank must run a fuel filter.