ok so on the needle valve i put it in the 3rd, and 2nd slot and it was running too rich, but on the first slot its running too lean.
the main jet size is a 210. bike has been bored,intake,exhaust. do i need to lower the main jet size and try it, cause when i got the bike it was on the 3rd slot on the needle valve and 210 jet was plugged up with gunk, cleaned the gunk out and it was boggin so bad when i took off. so this is where i am at. help, should i move it back to the 3rd hole and put a 170'ish main jet??????

 

yeah that sounds like a big main jet. I have a 128 main jet in mine. but it is only bored 2mm and aftermarket exhuast on it.

 

How big of Mikuni carb? 210 main seems extremely huge.

I tried a mikuni before I restored my '83 200x and could never get it to run right, after my restoration and engine mods I used a XR200R carb (keihin carb) and only run a 120 main jet.

I would do an advanced search of the forum with "200X and mikuni" and search title or body and find a member that runs a mikuni carb on thier X.

Jeff

 

ok so the 150 main was waaaay too lean , so i tried a 175, and same thing
so i used a 200, and now i got it to try to run, still sputtering a little . drove it around for 15 min or so and still to lean. I guess i need to go back to the 210 or perhaps go bigger to the 220. but if i remember correctly the 210 that was in there was too lean on top??? im so confused , from changing things aroujnd so much!! ugh!! whadda ya guys think, i know that these jet sizes sound way big, but it just wont run with anything smaller. i want this headache to be over

 

Ok...couple more questions. You said it is bored oversize, is it a high domed piston and if so what compression ratio...10:1 or 12:1.

You said intake and exhaust, by that you mean just new valves or ported and polished also?

Stock or aftermarket exhaust system?

Also is it lean at idle as well as full throttle and in between?

Check this site out... the paragraph under FIG. 7 is one of the most useful things I've ever seen for jetting a carb.

Carburetor Theory 101

 

ok, so the 210 main jet was too much , i think. now i have a 200 main jet in there and moved the needle jet pin to the 3rd and then 2nd hole. Well here's my theory so tell me if im wrong. The timing is so advanced that just putting at a constant speed it cuts in and out, blab blab etc.. but as soon as you give it some throttle and roll with it at a constant acceleration it doesn't sputter, it runs damn good, just still lean on top, could this be caused because the timing is advanced and there is no back pressure?????? this is killing me, i work 12 freaking hours an then go home and work 5 or 6 on the bike trying to get it lined out for the weekend ride

 

Will the engine idle my itself? If it does what color is the plug after it just idles for 5 minutes?
Could maybe be your pilot jet or pilot screw adjustment....I'm not really familiar with the mikuni carbs but the pilot jet and screw generally control the low speed.

I'm not really sure what to tell you about the advanced timing....Thrash may chime in and help you with some knowledge there.

Answer these questions for me.
What size mikuni carb are you running?
Stock exhaust?
Regular piston or high compression and if high compression whats the ratio?

 

What size mikuni carb are you running?
its a 28mm inlet, flat side carb

Stock exhaust?
exhaust seems to be stock coming out the motor, but there has been a slip on put on the exhaust right after it passes the back fender

Regular piston or high compression and if high compression whats the ratio?
ew i dont know this, compression may be stock, i was just told its bored .30 or .50 over, but i dont know

it idles fine, looks a little rich idling, cuase of the smoke coming out the exhaust. just sputters driving it if your not into the throttle