Help Please!!!!

[B.C.#11TRX400EX]

I no this isnt a 400ex but i figured you guys would no more about jetting than any other forum so i have a 1985 Honda ATC200X its bored over .75 and its got the stock pipe,Mikuni carb, and UNI filter i dont think the jetting is right so will you guys help with what we should do

Thanks,
Blake

[Ntensweapon]

Care to offer more details? What is it doing that makes you think jetting is not correct? What is the jetting now? What does the plug look like?

IMO it should be real close to stock jetting. Maybe 1 or 2 up on the main.

I recommend taking it apart and give it a good cleaning and document your jets. Research stock settings. Start at 1.5 out on air/fuel and report.
Perhaps CJM or hondasteve with chime in.

[CJM]

^ I echo this advice.

What is it doing, back firing, running lean or rich (yank the plug and see), does it have starting or idling issues? Etc..need to know more.

Id guess at most your gonna probably be 1-4 sizes over stock..probably around 1-2 more than likely.

[B.C.#11TRX400EX]

I dont know wat size the jets r we just bought the carb brand new off ebay and took the old carb off I think the stock pilot jet is 38 with a 145 main, when I give it gas it pops on dexcel and the idle is way down and its running fast like the idles turned up but its not its way down and when we ride it and put it in 2nd it wont rev at all so it just revs in 1st

[CJM]

Too lean pilot and to lean main.

Up the main a size or two and turn the air/fuel screw (if it has one) out another full turn.

Id also pull the plug and verify whats going on. White is lean, black is rich.

[B.C.#11TRX400EX]

Ok ill check the plug, so i guess a size bigger in the main and a turn on the F/A screw, should we get a slip on or is the stock pipe fine?

[B.C.#11TRX400EX]

Ok so heres the plug, wat should i do about the carb right now?how many screws on the F/A screw? Bigger main or smaller? Bigger pilot or smaller?

[DragonGunner]

I have a 84' 200X an a 86' 200X. the motors are very different, not sure what the 85 is but should be a 5 speed like the 84'.

Your plug is black so your running way rich which is why its probably bogging in your second gear. My 84' manual says the main jet is 108 an the pilot screw opening is 1 1/2 turns out.

spark plug = NGK DR8ES-L gap at .024 - .028

[B.C.#11TRX400EX]

its a kick start bored .75 over stock and its got a Mikuni Carb, i screwed the F/A screw out 2 turns, do u guys want me to take the carb apart and tell u what size jets are in it? i ran it a while it idles high but i cant go past 1/2 throttle in any gear i just found out so what does that mean?

[B.C.#11TRX400EX]

Mikuni Carb has a 15 pilot and a 95 Main (Mikuni Sizes)

[JOHNDOE83]

keep turning the air screw out till it stops popping on decel, if it goes to 4 turns and still pops get a bigger pilot jet.

See if your needle is adjustable and buy some bigger main jets from www.jetsrus.com

Stick a stock 400ex main jet in there and see what happens?

I bet it runs alot better?

[B.C.#11TRX400EX]

will stock 400ex main fit? there Keihin and this is a mikuni carb?

[DragonGunner]

Did you start with a new plug? Did your 3 wheeler run good at anytime before the carb changes? So it now idles an runs good except past half throttle...if thats the case, an your having problems still withpoor performance at high speed = check ignition timing which = improper valve clearance, faulty cdi, faulty pulse generator (I've had this problem several times), faulty advancer.

Or you could have low fuel problems = clogged fuel line,clogged fuel take breather (had that problem before too),clogged fuel valve, clogged fuel strainer in tank.

Can you take the air lid off an run it an see what it does, your plug shows it needs more air......good luck an keep after it.

[B.C.#11TRX400EX]

Ok here we go!! we paid $300 bucks for this 3 wheeler and rode it bout an a hour and it smoked like crazy, we checked the oil and it had no oil in it at all so we bought a shindy piston and rings .75 over, new stock cam, new valves and seats, so we rebuilt the top end put it back together and bought a Mikuni carb, UNI filter, no lid when we got it, put a tank of gas in it and to get it started for the first time after the rebuild we had to pull it behing our truck so we finally got it started and now this is where were at, it runs after about 5 or 6 kicks, it will idle but its idling high so i adjusted the idle screw and got it down a little bit but it still idles kinda high, i adjusted the F/A screw 2.5 turns out so now it dont pop on dexcel but when i rev it it wont rev past half throttle and then ill let off and it will idle real high, so im wondering if i need to change the jetting down a size or 2 or what i need help hahaha!!

[B.C.#11TRX400EX]

Here it is running

[JOHNDOE83]

I run keihin or minkuni in the same carb before, there is a conversion chart on jetsrus .com

[B.C.#11TRX400EX]

sorry that was supposed to be a video but it didnt work, so im thinkin about going down to a mikuni size 80, 82.5, or 85 on the main jet if i put smaller main jets in there will i be able to go past 1/2 throttle and it run a lot better you think? or do i need to do something else to it too?

[DragonGunner]

Did you get this carb off ebay? I have heard they sell some cheap ones on there, an people have told me they are junk. I would tear down an clean real good the old carb, you know it ran with that before the rebuild.
That would tell you if this is carb related or something else. Even if your jets were way off, it should get past half throttle, my only suggestion is try another carb.

[B.C.#11TRX400EX]

Yeah but its Mikuni its made well, but the jet sizing is just different from Keihin

[250x_kyle]

just keep playing with it till you get it running right some times it can be a major pain. by the way it would be bored over .075 .75 is 3/4 of an inch

[B.C.#11TRX400EX]

hahaha yeah i ment .075, yeah we adjusted the needle in right spot we just need to get smaller jets and it should run better, were gonna buy the 6 smaller sizes and see what happens on the main and we'll probably just keep the pilot the same