Ok, so let me start by saying that carbs blow my mind. I understand the general principals, but this not not enough to get the job done.
To start:
1)1998 Yamaha wr400 with a 2002 yamaha 426 top end and I believe the wr400 carb.
2) 0ft elevation currently, soon to be 725-1000ft. Temps in the 70's, high humidity normally 60-100%, spirited street riding, some offroad.
3) Full Yoshimura RS3 exhaust, airbox lid removed, '02 426 top end as mentioned earlier. Thinking of adding airbox vents in the near future after everything else is sorted.
4) Stock Jetting: Starter jet 65, 42 or 45? pilot jet, 162 main jet. (from research)
Current Jetting: 82 starter jet, 45 pilot jet, 170 main jet.
5) From what I can remember (it's been so long ago) the bike ran fine. There was a slight pop on deceleration, so I thought I would richen it a tad (never touched the jetting as the bike was new to me). The second I touched it it went to hell. popping like crazy, running rough. Couldn't get it started. Long story short, when I adjusted the fuel screw (zip-ty racing), the rubber o-ring broke in half and lodged itself up there. I got a replacement spring, o-ring, and washer, threw in a new spark plug, and it essentially started right up. In attempts to confirm the pilot circuit, I found adjusting the fuel screw had no affect from almost shut to all the way open (bike warmed up etc). I also noticed that when I came to a stop, the idle was way high (3500rpms or so). If I slowly released the clutch as if I was attempting to stall the bike, as soon as the clutch caught (and I then pulled it back in), it would return the bike to normal 1500rpm idle that is at when idling warmed up. Getting fed up, I took it to a shop who said that my pilot was too lean.
6) When starting, I pull the choke, start the bike, and let it warm up briefly while choked and idling high(10 secs), then I press the choke in while I gear up and let the bike idle at it's normal 1500rmps. I try not to leave until it reaches at least 125 degrees as indicated by my temp gauge. Once running at low RPMs, when I pull the clutch it will return to 1500 rpms. Once I run the bike above 3500rpms to redline the idle will return to 3500 or so until I bring it down by dragging the clutch, which is annoying at stop lights as I have a loud pipe and people look at me funny. As far as I can tell, once the bike warms up (140-180F) the problem is a little worse.
I haven't ridden the bike much since I owned it, and there was supposedly less than 2 hrs on the new 426 head, but it was killer noisy when I did ride. Checked the valves and they were embarrassingly waaay tight. Having the head redone with SS valves, new springs etc, and seats re-cut. When I install that, a new air filter will be going in as well.
Should I wait until I re-install head and air filter before I mess with the jetting? I'm afraid of running way to lean and risking damage to my new head. Talked to someone with a similar build and he says he is running a 50 or 55 pilot. I know I should only do one thing at a time as there are so many factors that can affect the way the bike runs, but since I have the bike apart I want to get as much done as possible.
Thanks for any and all wisdom you can bestow upon me.
-Alex
EDIT: And the air jet (?) on the right side just above the fuel line and below the phillips head screw on the right is a 90.
