View Full Version : how to tune a carb
yamahaman89
11-07-2009, 02:21 PM
my 86 200x keeps flooding out the spark plug when i try to start it and is backfiring alot....so i plan on ordering a rebuild kit for it...so my question is how do i set the jetting and the air/fuel mixture??
4cfed
11-07-2009, 02:25 PM
does it do it no matter if choke is on or off??? sounds like the float is stuck... start by taken the carb off and cleaning it out really good.. mine got stuck when i would wheelie and start pourin gas out of the vent tubes.. i cleaned it out and its been fine
yamahaman89
11-07-2009, 02:29 PM
well i will put it on full choke and the first kick it will fire up for a few seconds and die then i will go to half choke and it will flood out even if i skip the half choke and put it on no choke it will flood out the only way i can get it to run is to clean the plug and heat it up with my little torch then it will fire up (plug is brand new)
85Tecate
11-07-2009, 03:14 PM
Set your float level for one. Sounds like either your float level is too high or your needle valve is not seating properly. You dont set jetting....They are seperate brass fittings with a certain number on them. Your carb kit should come with the correct ones but match the numbers just to be safe. I would start with 1 1/2 - 2 turns out on the mixture screw and fine tune it from there.
It also wouldnt hurt to change your plug again, it could be wet fouled. And YES it will still fire with it wet fouled but may not fire under compression. First thing i would do is change the plug again.
Dirtcrasher
11-07-2009, 03:57 PM
"Tuning" a carb can be one tough job. Especially if your not even sure if it's the right size for the motor you have and the mods within it!! Depending on your mods, you may not have much tuning to do at all.
In your case, a thorough cleaning (removing everything that comes off within that carb) will more than likely take care of the problem. If the 200 is stock, then stock getting will probably be very close, if you have an open exhaust or removed the airbox lid, you will need a larger main jet and possibly need to move the needle up one notch too.....
NEVER make more than one jetting change at a time and record how it started and ran for you, under a load, idling and wide open throttle.
DAMMIT put up a very nice "Sticky or Read this" about jetting in one of the forums. Most of it won't makes sense to plenty of people but anything you learn today is more than you knew yesterday!
Be aware that SOME of the carb rebuild kits out there have the WRONG air screw, and air screws are very important for starting, idling and up to 1/4 throttle. Match it with the old one and then use anti seize on the screw. The thread pitch is off on the 86/87 200X kits from what I have found and it will ruin your carb, screw and or both.
Spend some time using the 3WW search feature, allot has been said about jetting and sometimes a simple oring is a large problem......
I do suggest you fix your stock 26mm?? Kehin carb and avoid the knockoffs on EBAY. Just my suggestion, they work great for some people and not so great in other cases.
85Tecate
11-07-2009, 04:44 PM
I bought one of those knockoffs on ebay for a 185 i had and ill tell you what, for 60 bucks it was a hell of a carb.......That thing ran perfect and would fire off first pull in the dead middle of winter. I would definatley buy another if i came across an issue.
HaggLE
11-07-2009, 05:04 PM
What plug do you have? maybe thats the problem.
Also, if you do put a kit in your carb, screw the idle and idle mixture screws in counting how many turns it was, that way you can put it back in the same spot as a means of comparison.
yamahaman89
11-09-2009, 12:20 AM
i have a NGK plug....within the last couple days the trike has been firing up just fine i don't know maybe she just had a bad couple days but when i got the trike the guy said it was sitting in a barn for awhile so i just assumed id get a rebuild kit anyway....im probably just gonna invest in a manual again(cant seem to find mine) Thanks guys
MonroeMike
11-09-2009, 12:31 AM
http://72.52.143.80/~trikes/Manuals/ATC%20manuals/86-87atc200xservicemanual.pdf
Texas 200x
11-09-2009, 10:52 PM
If your gonna mess with a carb search this in the quick search. Carb Jetting 101: Terms, Tips and Jetting Theory. Sorry I don't know how to link a old thread here.:lol:
MonroeMike
11-09-2009, 10:59 PM
^ http://www.3wheelerworldforums.com/showthread.php?t=55086
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