200X Valve Lash & Fuel

[MPNX2]

Ok I think I have figured out the jetting on the 200X and now iy seems to run ok. I have installed a new cam with higher lift and duration. The paperwork that came with the cam says to set the valve lash at .004. IS this the same as adjusting the valves? According to the book they should be .003 and some say .002 which is what it is set at now. I just dont want to ruin my new top end so I am double checking...

[MPNX2]

The bike was really hard to start but it finally did. I am still running WAY too rich!!! The plug will get real wet and I have to pull it out if the head and let it dry and then it will start. But it sounded like it was ticking too much at .004".

[MPNX2]

What meters the fuel going into the combustion chamber during startup? I have gone a step leaner on the clip and also went leaner on the pilot screw. The motor will only start if it is warm. If I can find out why the plug is getting wet all the time I might be able yto slove the problem.. Anyone??

[MPNX2]

Oh someone has to know..

[ATCMedic]

When "setting the valves", you are setting the valve lash. I always run .002" because .003 always ticks and it sounds like you have engine problems. I am not sure why the cam manufacturer suggests .004, if they have an 800 number you might want to call them to find out if they used and exotic alloy in the cam or something, if not you should be safe running .002". As for the fuel metering question you had, the clip and air screw meter the amount of air going into the engine at idle, the small jet with the flat head screw slot is the idle jet and meters the fuel going into the engine at idle. Have you changed out the carb on t his machine? If not you shouldn't need to change the idle jet, if so I would try putting the idle jet from your old carb in and see how that works. Also try raising the needle another slot or two to let more air in to dilute the excess fuel and adjust idle as necessary.

[Tri-Z Pilot]

I think he's running a 26mm xr carb, he shouldnt have to mess with the pilot since the xr200 is basically the same as the 200x right?

[ATCMedic]

I think he's running a 26mm xr carb, he shouldnt have to mess with the pilot since the xr200 is basically the same as the 200x right?

I think you are right, the xr200 carb shouldn't need to change the idle jet on the 200x.

[MPNX2]

Yes I am running an XR200 carb. I have changed out the plug and it starts a lot easier now. Hard to believe I already fouled a plug I havve only ran it for maybe an hour. I have leaned the clip to its highest setting and have turned the piolt screw out a few turns. I am going to go and ride it today (if it starts) and see how it runs.

My old stock carb has a 115 jet in it if I put that on in the 26mm carb instaed of the 135 that is in there now would it be way too lean? I figured since the carb was bigger it needed more fuel so it uses a bigger main jet. Is this true or would the 115 work??

[Tri-Z Pilot]

You see, this is where jetting starts to confuse me here, a stock tri-z uses a 32mm carb with a 470 main jet, and if you switch to a 38mm carb, the reccomended main jet is like 320, now this confuses me. Didnt you just rebuild your engine? If so go read my "extreme break in post", it raises some new information on how to break in a four stroke.

[MPNX2]

Yeah that seems very confusing to me as well. I feel that if I were to put the smaller jet in from the stock carb it would use the same amount of fuel as the stock carb did. Or maybe I dont know what I am talking about....LOL


I am going to read that post....

[Tri-Z Pilot]

It would use the same amount of fuel 3/4to full throttle, but there would be more airflow making it lean, I think,lol! I dont know, carb settings are very tricky, did you read the article on the main page for 200x mods, they have a 26mm carb there, it might say something about the jet settings.

[plkmonster2]

so your talking about 2 thousandths? that is REAL thin.... i would think the lash would be 12 thousandths, like .012 .002 is like a sheet of paper.

[ATCMedic]

so your talking about 2 thousandths? that is REAL thin.... i would think the lash would be 12 thousandths, like .012 .002 is like a sheet of paper.

Yup, .002" = 2 thousandths. I know it sounds too close, I thought that the first time I rebuilt a 200x motor and set the lash. If you set the lash at .012 it would sound like your top end was coming apart from all the ticking.

As for the jet, I would try the 115, it might be the 135 is too much for your motor. Run it like that for a few minutes and check your plug.

[plkmonster2]

wow, were do you get a feeler gauge to set them THAT close?? dang, my cheezy one only goes to .010 is this done hot or cold??

[plkmonster2]

also, ive set mine at .012, 225dr, but it was looser than that when i set it, and it only ticks for a few seconds till the oil reaches the valves.