Posted 15 April 2012 - 08:40 PM
OK, I finally stopped p1ssing myself about the XR400 not starting and pushed it from the barn to the garage got my tools out and tried to figure out why it would not start.
Remember in the last episode the XR100 started on one kick after I inadvertently left the gas on and my XR400 would not offer anything.
So, I first tested for spark by pulling the wire connecting a spare plug and then having my 13 yr old son watch for spark while I spun the motor by holding decomp and kicking the beastie. He said he saw blue spark so I knew it was on to the carb then.
I dumped the gas in the bowl, pulled the bowl and removed my high speed jet, a 152. It appeared to be clean and I gave it the breath test. Why does metal marinated in old gas taste so bad?
Next I pulled the idle jet, a 60 and inspected it. Got light thru the pinholes on the sides but nothing down the middle. Hmmm that may not be right. I searched through my electronic parts bin, found a diode and poked one lead from the diode into the pilot jet hole. Doesn't get through, feels like the diameter of the metal lead on the diode is too large to pass through what should be an opening in the jet. I find a small electrolytic capacitor and poke it through. Tough at first then goes through easy. I repeat several times until a visual inspection shows what appears to be a normal passage through the middle of the jet then I begin putting it back together. I put in the main jet, tighten it. I put in the pilot tighten it. Then I put in the white plastic thing that I always find in the bottom of the bowl but it seems to want to be on the main jet, but never stays there. I don't know what that thing does but I'm starting to hate it.
Now I check the air screw in front of the carb is 2 1/4 turns out.
Finally, bowl goes on, screws go in except for the rear one, can't figure out how to hold my hand, it will not bend the way it needs to. Using long pliers and my screwdriver I manage to get the rearward screw in and tight.
So, now is the real test. Choke on, gas on, wait for 30 seconds or so, kick slowly about 4 times to pull something good into the combustion chamber then a hard TDC kick and BANG, I get a one kick start. Sweet!
So I let it fast idle for a couple minutes and then it's time to really test the idle circuit and pilot jet. I put it in gear, ease off and idle it all the way around the block with not a single miss, spit or burp. That's what I'm talking about!
Tomorrow night I will test the half throttle and WOT positions to see if all is well again. Then it might be time to hit DMV to see if I can get a plate.