05 Wr450 suddenly rich!
Posted March 14, 2006 - 11:07 PM
05' WR450 settings during last ride:
Main jet: 168
Pilot Jet: 48
Fuel screw (turns out): ZipTy - 1.5 turns
Needle model/Clip position: JD Red 5th clip
Air box: Snorkel out, "punch-outs" removed
Pipe: stock, plug removed
The temperature is about the same as when I first jetted it and it was spot on then.
What I have checked / changed:
Pilot jet changed to 45
fuel screw completely closed but still a little rich.
Exhaust: all within specification but on the tight side (around 20mm)
Intake: one at 9mm all others in specification (around 10mm)
Spark plug: was fouled but now new, this almost fixed the jerky condition.
Air Filter: clean
Carburetor: removed and thoroughly cleaned, all jets removed and cleaned and all passages blown out with compressed air.
Has anyone had the jetting change so drastically that it required the fuel screw to be closed to run when the jets are within the recommended sizes? I am using fresh fuel, but could that be the cause? The humidity has been higher lately, how much of an impact does that have? Is there any circuit in the carb that that could be clogged that would cause it to be rich?
Posted March 15, 2006 - 04:50 AM
45 pilot is low enough for high humidity with 1.5 turns out on the fuel screw. Move the Red needle to clip #4
Put in a 160 main jet on high humidity hot days.
Posted March 15, 2006 - 04:55 AM
Posted March 15, 2006 - 12:27 PM
Posted March 15, 2006 - 05:09 PM
made it home all safe and sound i hope!Sorry we didn't get to ride together BUT next time watch out!
I am glad I had my sunglasses on Tom! Your Anniversary Edition YZ502 Super Bling Bling bike was so clean and bright I was embarrassed to wheel my super piggy over! Thank Ursala for the great sandwiches. We went to Westpoint the next day and had a blast. Hope to see you at Durhamtown or the Ridge again soon.
Posted March 15, 2006 - 09:12 PM
Very rich condition causing a fouled plug, poor idle with the fuel screw fully closed, hard to start even with the hot start lever.
Changed pilot jet from 48 to 45... better idle and starting but fuel screw still had to be fully closed.
Moved clip up on needle... almost there but fuel screw only 0.5 turns out???
Then I specifically cleaned the Air Cut Valve (ACV) with compressed air now it is working the way I think it should. The fuel screw out about 1.75 turns, perfect idle and it ripps again.
On my last ride I stalled in a fairly deep mud puddle, it is possible that something was sucked up through the drain tubes into the ACV. Does it make sense that a plugged ACV would make it richer?
It will be getting hotter in about a month here in Texas so I will leave the pilot jet and the clip in place. Do you think this is a good idea?
Posted March 16, 2006 - 12:10 AM
Jetting is fun but give me EFI! I am ready to replace my WR in 2007!
Posted March 16, 2006 - 06:41 AM
They will have to really boost the electrical output to run the fuel pump (if they go electrical).
Someone could almost put together a kit with off-the-shelf parts:
Throttle body off of a 1000cc V-twin
larger charging system from some desert racing kit
Small fuel pump like the one Holly uses in their aftermarket kit
There are several control modules like mega-squirt, or Holley... The trick would be finding one small enough.
Have you ever ran across a schematic of this carb?
Posted March 16, 2006 - 03:49 PM