Installed JD Jet kit... now my WR400 spits flames...
Posted May 06, 2011 - 10:58 PM
Prior owner installed 170 main jet. Haven't checked actual size on pilot jet. It's supposed to be 45. I'll verify tomorrow. I have on size above and below the stock pilot jet to play with.
Posted May 07, 2011 - 07:18 AM
i ended up on my 444 project 47hp- 39ft lbs at the tire.
the bike had a pretty flat power band.
had a 168 in it to start i could tell it was running awfully lean all over the place.
jetted it to a 170 and it got a little better.
after about 8 pulls on the dyno and drilling my 170 out to a 184 the bike has perfect, flat air fuel ratio.
i need to spring for some "real" exhaust...the stock, bashed up header i have along with the 8" cut down muffler dont help the bike a bit.
i came across a nice ti- slip on a buddy had sitting on a shelf in his garage, im thinking after i froze the header and got rid of the dents and figure out the muffler not only should it make a little more power down low but will quiet it down considerably.(its REALLY loud).
i think that will do til my birthday(as i found a really nice full leo vince mx/sm system for my bike) as i planted the ness info where my girlfriend may pick up the idea.
good luck on the dyno...its a fantastic tool to have available.
Posted May 07, 2011 - 07:39 AM
If that didn't do it, go to a 48 pilot, and re adjust fuel screw.
Like others have said, it is NOT the main doing that
Posted May 07, 2011 - 09:36 AM
For now, I'll take it up a 1/4 turn and then a 1/2 turn to see if it eliminates the issue. I cleaned my air filter as well as it's been a few rides, maybe it's leaning out the mixture as well (less air = rich though... hmmm, this probably will make it worse, haha).
We'll see how it goes going forward.
Posted May 07, 2011 - 11:22 AM
Next, do teh fuel screw set up:
Fuel Screw/Pilot Jet
Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.
Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.
*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***
Turn the screw in until the idle becomes rough or the bike stalls.
if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.
If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.
Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.
If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.
If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.
If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.
Posted May 07, 2011 - 02:42 PM
Posted May 07, 2011 - 06:47 PM
So, just for shits and giggles, slap on your old header and see if it's still doing it.
Posted May 07, 2011 - 07:03 PM
I'll just post my dyno sheet from tomorrow and we'll discuss. If all it is is popping on decel, I can deal with it. It's those hills climbs that I gotta sweat!
Posted May 08, 2011 - 04:34 PM
Posted May 08, 2011 - 06:26 PM
hope you didnt pull slide out to change needle,if you did sounds like throttle plate in upside down,hole goes towards the bottom,pull carb back from front rubber and look,bike will shoot flames and only run with choke
Yep, that is not the case. Runs without choke, only flaming on decel.
Posted May 15, 2011 - 11:09 AM
I've played with the fuel screw. I'm going to tool around more with it to see what's going on. It's been my experience thus far though that it isn't the problem here...
Where would I look next? Valves?