99WR400 pops/fouls plug
Posted February 26, 2003 - 08:29 AM
Posted February 26, 2003 - 10:21 AM
My '99 had started fouling plugs left and right last summer. (The cam timing on my bike is set to YZ specs so it wants to be leaner than stock anyway, but what I'm saying may give you some idea as to what direction to go.) Before that, I had the plug that originally came with the bike. It seems that the jetting just wasn't lean enough. I am running a 35 pilot jet and the pilot air screw is set equal to a 45 paj. (BTW, I'm usually at sea level.) Leaning the pilot circuit by going from a 65 to a 45 pilot air screw really helped both the plug fouling and made the bottom end much snappier. I'm runnning the stock muffler with a homemade buttplug, er..baffle.
Some other things to check:
The spark plug cap had gone bad in '00 and I had to replace it. The bike fouled plugs intermittently. Those damn caps are expensive! Get a little Motion Pro spark tester to make sure the cap is still good. Also, check that it is attached firmly to the high-tension wire. It screws on to the wire and can come loose. One thing that really helped a lot was unplugging the sky blue wire. (It supposedly weakens the spark at idle for noise emissions control when it's connected.) Just pull it out, tape over it and it will definitely starter easier.
Posted February 26, 2003 - 11:14 AM
Also there is MUCH to improve on your stock jetting and your accelerator pump operation.
Posted February 26, 2003 - 05:10 PM
Posted February 26, 2003 - 05:29 PM
Posted February 26, 2003 - 06:00 PM
Posted February 27, 2003 - 05:19 AM
Where is the sky blue wire?
yes, it idles fine once it warms up and even during warm up with choke on(choking 30seconds or so).However, it will not idle when the miss/ pop starts. It is intermitent, but seems to be pretty regular now. Last 3 rides every time. But once I run the $hit out it the problem goes away until I stop for a while and it re-occurs out of the blue. It has an aftermarket hot start that runs to the handle bars. I think they called it a Hawkins hot start, seems like I remember seeing Motion Pro on the tube. Your right though, During a race I endoed, got back on and fired it up and began riding, ran like crap, evidently my leg or boot flipped the hot start on, I stopped but no idle, when I took my helmet off and cranked again I heard the air sucking in thats the only way I figured out what was wrong. I remember now that the pop/miss its doing now sounds exactly like it did that time. The problem is I wonder why it idles so good?? Good catch, I'll look that over as well. Thanks
Posted February 27, 2003 - 07:55 AM
Posted February 27, 2003 - 10:02 AM