YTM200L carburetor problems?

[kawaboy-zx12r]

i have been tweeking on my carburetor lately on my 1984 YTM200, a couple days ago i was messing with the pilot screw and it was running WAY WAY better that it ever has, i couldnt keep the front tire down in 3rd gear, it felt real flippy in 1st 2nd and 3rd gear, way more power than i ever thought it had, i then turned the pilot screw in to count how many turns it was out and i never got it to run that good again . so yesterday i pulled the carb, disassembled it and soaked it in a gallon of gunk over night, i went to the yamaha shop and got a 112.5 main jet and ordered a #25 pilot, pilot should be here tomorrow. i put it back together to see if cleaning it made it run great like it was...it didnt. i also notice that it idols fastest with the pilot screw ALL the way in...seated. why would it idol best all the way in like that? i couldnt read my old pilot jet so i orded the new one to be sure its the correct #25 size. it does run fine and idols good but it just does not have the powerband like it did. Thanks

[YTZ drew]

Weather can play a big part in performance. If it's running well but doesn't seem to have as much power as it did previously, it could simply be due to air temperature, pressure, or humidity differences. I know that my street bike is a totally different animal on a dry 50 degree morning than it is later in the day when it's 75 and slightly humid.

[RubberSalt]

You may have your idle screw in to far. Back the fuel screw out and then back the idle screw out.

Do you have a manual for this machine?

[kawaboy-zx12r]

i found the problem this morning, i took the gas tank off and checked all the wire connections, sure enuff one was not pushed all the way in, now its running great again. BTW it was getting spark and it was running, just not real strong...now its a wheelie machine again Thanks

[RubberSalt]

recommendation: print off manual, sit it next to the toilet. You'll know that machine better than you could ever imagine :-D

[kawaboy-zx12r]

i spoke too soon, it was running real good earlier now its not getting into the power band again. something i notice is when its running real good and has a strong power band, i can hear something rattling in the engine, when its not running strong that sound isnt there. i wonder if i have a valve sticking or something. i will check and adjust after it cools down.

[kawaboy-zx12r]

ok, good to go for real now. would you believe.... after i soaked the carb overnight, bought new jets, reset valve lash, checked ALL wiring, cleaned tank out....still not running strong. today i went and spent $2.37 on a new spark plug and it runs perfect again....super strong! i ruled out the plug in my previous checks because i just put a new one in it last year, i guess it went bad from sitting over the winter. all is good now!

[RubberSalt]

Did you ever find your rattle?

[kawaboy-zx12r]

im not sure i should call it a rattle, its just when the power band kicks in and its pulling real hard it sounds....different than it does before it hits the power band.

[kawaboy-zx12r]

ok, it ran real strong for a few days, today i messed with the fuel screw and its not running right again, even after i put the fuel screw back were it was 1.5 turns out. i pulled the plug and its real odd, 1/2 of the creramic is nice tan and the other 1/2 is dark from carbon, what would cause this? here are picture of both sides of the plug.

[yaegerb]

So first off, last I checked, a ytm200 is a four stroke so you don't have a powerband. Such nomenclature is reserved for two stroke where cylinder combustion and exhaust resonance synch to produce a "turbo effect" thus resulting in the common phrase of a "powerband". Second you need to set your carb back to stock specifications and start from there. Also make sure you don't have air leaks around your intake manifold.
Main: 112.5
Pilot: 25
Float height: 21.5mm
Needle clip: 3rd from top

[kawaboy-zx12r]

that is how my carb is set up. i put a brand new 112.5 main and a new 25 pilot in a couple days ago float is set dead on 21.5mm height and clip is in 3rd position, fuel screw is 1.5 turns out. before i did all that i soaked the carb in gunk overnight blew it out and ran fishing line thru all the little holes, it still ran the same, i then bought a new spark plug and it ran great with the new plug for a couple days. i just did probably 100 laps around my yard and laps 22 and 23 where good and strong, before and after...not so much. i really believe this is an electrical problem, since it ran perfect for a couple days when i installed the new plug. i am starting to think its the stator or ignition coil making weak spark intermittently. and yes it does have a definite power band when the rpm range reaches peak performance and the front wheel comes up own its own, weather you want it to or not.

[yaegerb]

is the spark fat and blue?

[kawaboy-zx12r]

once again i think i found the problem. my friend stopped by when i was putting my new jets in yesterday and i was distracted and didnt tighten the air filter boot to the carb so i think i was sucking air, its running strong again today after i tightened the clamp for the air filter.