ATC200x carb problems

[900EX]

Just got my 200x project finally back together. But I am having a heck of a time with the carb. These are new to me, as when I was a kid and these were new old mom and dad would not let me have one, so I could use a little advice. Here is what I have done to the engine. .030 over Pro-x piston. Head ported, race springs. New bigger cam(.340 lift, 266 duration). UNI air filter, and left air box lid off. Cobra exhaust. Carb needle in third notch, and 112 main jet.

I have spent over 8 hours doinking with the carb to no avail. I finally have it just about idling but it will die sometimes. I have the idle mixture screw almost all the way in. Which way makes it leaner in or out? The manual dose not say, and as mine seems rich no mater were it is. It was idling real fast and then would drop down till it dies but I seem to have that gone now. Now it stumbles pretty bad when you give it gas when in gear from a idle coast. I cant seem to get rid of it. I know it needs a bigger main as it is popping at full throttle. I have some coming. But the idle and stumble I just cant seem to figure out. I have had the carb apart twice checking it and nothing is clogged. I have double checked the cam and ignition timing, both are right on. Any ideas?? I am stumped. The cam should not affect the idle as it is not that big. Hay any one in the Batavia- Cincinnati, OH area? Ill pay for a little carb help!!!! LOL Thanks for any help!

[BigReds Forever]

screw in = lean, out = rich. sounds like kinda the same problem im having with my 200s, which im prety sure has a similar cam in it. doesnt idle to well, pops on the top end, and seams to run rich no matter what. I have no idea whats going on. I was thinking of switching to a hotter plug and seeing how that went. Hopefully some one on here can help us out.

[Kevo225dx]

Check to make sure your choke cable is adjusted properly. Also, check your float level. Hope this helps.

[xman23]

i have somewhat the same problem with my x, i think i have the same cam as you, is it a web cam? mine wont idle till it gets warm then it does, i messed around with it for hours, i just cam to the conclustion thats its old and its a honda, so its gonna be cold blooded

[900EX]

I was going to check the float level but as it is a plastic float I see no way to adjust it. So figured it would be a wast of time. The choke is off as it is a lever it is pretty easy to check. Funny thing is it seams to idle better when cold than warm. Go figure. I would think it should not run with the mixture screw all the way in. But it runs with it all the way in, and is still to rich. And the screw is not bent or damaged. All the guts of the carb were just replaced. I keep thinking about getting the new carb that is sold on Ebay that has the accerlator pump. It is suposed to fit. Not sure if it is a web cam. I bought it from Biker Chicks Ltd. on Ebay. Sure sounds like I am not the only one with this problem. It is driving me nucking futs. I mean if I can work on Jets you would think I could figure out a carb problem!

[Kevo225dx]

The fact that your idle is better when could indicates a rich condition that doesn't change when you turn off the choke.

The plastic float should have a metal arm that "rides" on the needle and seat. You can bend this arm to change the float hieght. I don't know about your carb, but on mine there is a drain at the bottom of the float bowl. I just connect a piece of clear hose to the drain; open the drain screw; and hold the hose next to the carb. The fuel level should be slightly below the gasket.

I the float level is correct, I'll be stumped as well.

[super90]

In is leaner, out is richer, you can also adjust the float height. Did you try rejetting when you put the exhaust on? Try going down a few jet sizes.

-What size tires are thoes? 20s or 18?

[SWIGIN]

to help lean the idle try a smaller pilot jet try 5 sizes smaller

[900EX]

The Tires are 18s. I got two new sets of them with the two 200x's when I bought them. Might go to a bigger front sprocket, but I like the low end grunt. Lots of up and down hills on my property in KY.
I took the crab apart again tonight at work. Float hight is right on the money, but I am going to check it with the clear tube next. Thanks for the idea. There is no medal arm on this float all plastic, so not sure how one would change it if need be. I may have to find a smaller idle jet. Ma be the one that came in the kit is to big? I have a 112 main in it now but it needs bigger as it falls on its face and pops when wide open. Just wighting on them to get hear. But I may have made some headway. I turned the idle screw out. It really did not run any slower, but now I can tun in the mixture screw and kill it! So I think it may have been getting fuel from around the needle. I need to ride it and see if it helps the stumbling problem. But I had it idling in my hanger tonight for about 10 min. with no stalling. So progress! So we will see what happens when I put in the bigger main jet. Thanks to all for all the help!!

[TeamGeek6]

"I was going to check the float level but as it is a plastic float I see no way to adjust it. So figured it would be a wast of time."

Thats the most critical adjustment. Fuel level controls all the jets. On top of that, youve hopped the dickens out of the engine, and stuffed more fuel in, on a stock ignition? no wonder it wont run.

Start it, turn the gas off, see if it runs better as the carb starts to run dry. If so, the fuel level is too high.

God I miss the sand pits at Cleves...

[BigReds Forever]

what can be done on these 200 motors in terms of ignition? I dont know of any mods or aftermarket parts except hotter/colder plug. as for that all plastic float, if its off, you gotta do one of two things, replace it with a new one, or very very very carefully heat and bend that tab slightly upward. (dont melt a hole in the float!!!!!). Ive adjusted one on my red and it can be done, just need to watch the heat. This jetting thing is buggin me so much. Also, does anyone know what size carbs are on these trikes (on the 200s, and on the 200x) Is there any new quad carbs out there of similar size that could be adapted?

[Liquid-Darkness]

Here is a pic of tuning guide lines to clear up your carb problems. I would run the bike with the pilot screw out at least 1 turn from shut. Do some WOT plug and chops to figure out how your main jet is running. The chart says what throttle position effects in the carb. Your idle to 1/4ths throttle is your slow jet and needle clip position and needle tapper. I think a slow jet stock for that bike is a 38 you should try to jet your slow jet down to a 35 then 32. Try those to see what works best. My Honda shop manual for that bike says the stock main jet is a 110. If you are at a 112, try a 115 and 118. Some plug and chops should tell you how she is doing at WOT. Do these tests with a new plug, so you can read it clearly. You know, droping your needle one setting might clear up your rich idle. That and a smaller slow jet. What compression piston are you running? Stock is 9.6 to 1.
I recomend premium fuel for these bikes if it does not have a high compression piston. It lasts much longer then regluar gasoline. It also keeps your bike cooler. Can't go wrong with 20/50 oil either.

[900EX]

Thanks for the ideas and the diagram. It is stock 9.6 to 1. I only run 93 fule in both of my trikes. I am just waiting on my new jets to try some more tinkering. I might have a chance to check the float hight with some tubing at work tomorrow. But I suspect it will be OK, as I measured it and it was right on. I have the needle on the third notch, and that seams to be were it likes to be. Ran icky on two, and four. I just need to be able to get a bigger jet in it and get out and ride it. Hoping that with the idle right it will not stumble when you give it gas. Just a mater of being able to get a day off to go play. A day that is warmer than 30 or so would be nice! Thanks for the help!

[900EX]

Well I got the 200X out to play for about 4 hours this morning in the snow. Got the idle so so. Put the main jet up to a 120 and it seams very happy there. Boy that thing really pulls the hills on my trails. Just accelerates up them like you are on level ground. Almost ran over three turkeys going full bore down a trail. Don't know who had the bigger heart attack, me or the turkeys. But any way. The one problem I still have is even after a solid hour or so of riding it will stumble off idle. Say I am costing down a hill in first gear, with the clutch out. When I hit the gas it hesitates real bad like it is going to die. Could this just be do to the very cold temp? It was only in the twenties here today. Other than that it is running pretty good. Wish I would have had my good camera with me instead of just the phone. Thanks to all for all the help!

[edog]

Try putting the Air Lid back on.