James/Clark up date on jetting.
Posted October 21, 2000 - 08:25 PM
Posted October 21, 2000 - 09:55 PM
Posted October 22, 2000 - 05:11 AM
And Boit's advise on the MJ is right on.
Now after you master the PJ and MJ, ignore everyone but James and Clark . Seriously the next step is to dial in your needle. This litle baby is the difference between a WR that runs good (or so you think) and one that RIPS!!!!
My guess is (if you have a '00, WR timed, stock exhaust insert out, airbox lid off, riding at medium elevation and it's getting cold---45 PJ, Fuel screw around 1.75 to start, then turn out (counterclock) slowly. 170MJ w/ stock needle clip #4. This is only a guess. Remember to do lot's of plug checks in between, and right down your setting, temp, alt, and riding observations. Also now that it's muddy, you're air filter willget dirty fast and your carb vent lines will clog easily which will make the bike spit, kick, backfire, hesitate, etc-consider rerouting or kicking the mud off at rest breaks
Posted October 22, 2000 - 07:08 AM
You said that you tried my advise and now the bike runs a little better but is fouling plugs. I gave you some advise on how to clean up the lean spot but left plenty of room for you to experiment. Please post what your jetting is right now with the fouling problem and we will go from there.
Posted October 22, 2000 - 07:37 AM
Posted October 22, 2000 - 06:13 PM
When jetting you count the clip position from the top of the needle. 1st clip is the one closest to the top and 7th is the last one closest to the bottom.
I would recommend the following jetting based on what you have done so far. DRS #4 from top, 45 PJ at with the fuel screw at 2.25 turns or a 48 PJ with the fuel screw at 3/4 to 1.25 turns out (PREFERRED). The main jet selection is not causing your fouling problem. So jet the main based on top end performance, its easy to experiment with.
Posted October 23, 2000 - 08:52 AM
You are at a higher altitude and are using a richer #4 clip position than stock #3. The needle clip position affects fuel mostly at 1/4 - 1/2 throttle and you have said that it sputters at 1/4 throttle.
My suggestion again is to try clip #3.
(The standard YZ400 needle setting is DVR#4, your DRS#4 setting is close to 2 clips richer)
[This message has been edited by James Dean (edited 10-23-2000).]