FCR Carb fine tuning - starting help - WR400
Posted December 19, 2012 - 06:31 PM
Carb was too rich all round, fouling plugs constantly.
168 main (but mechanic said drilled bigger)
OBDXM (Aus version of OBDTM)
45 pilot (1 1/2 out)
EKP needle #2 clip
Runs very nicely with the new setup, no stutters and good power, except starting.
Dead cold it will start on choke
Warmed up won't start unless I hold the Throttle at 1/4 and then starts and idles perfectly.(same happened with 48 pilot)
I have read Williams post on setting the pilot and fuel screw which I am still fiddling with.
If I am reading it right.....if I turn the fuel screw all the way in and it still idles smooth I'm too rich and need to go down?
Just wondering...am I missing tsomething to get it to start with closed throttle?
Posted December 20, 2012 - 01:40 PM
My previous WR never needed the Hot Start, so there must be a magic combination there somewhere.
The bike still has a small stumble between 0-1/8th throttle once it is warm. Most noticable if I coast to a stop and then roll on slowly it has a but of a stumble.
There is no stumble if I whack it open and the rest of the range is great, so I guess I'll keep leaning out my pilot until it goes away.
My main problem is Jets are really hard to get where I am (bike shop is hopeless and really expensive), always have to mail order. I really thought the #45 pilot would have done it.
I will try to get the fuel screw set correctly this weekend now that it is close to right and hope I don't have to buy more jets.
I'm thinking I need to search the net for a parted out wr and get a hot start replacement, brand new are a rip-off.
Posted December 20, 2012 - 05:59 PM
So I'm guessing I need a #42 pilot ?!
Posted December 21, 2012 - 06:12 AM
168 still looks rich on the main jet. How does it pull WOT in 3rd and 4th gear up an incline? I'd think you'd want a 160 or at most, a 162
Keep in mind, the FCR jets are all the same for all bikes that use that carb (which is every MX bike).
Posted December 21, 2012 - 12:30 PM
I am running 162 main
EKP on clip #2
I'll definitely have to try 42 pilot.
I put screw all way in and still idled fine.
I'm suspicious about maybe the needle jet (emulsion tube) could be worn too so I might order a new one as well to be sure.
Posted December 21, 2012 - 12:34 PM
Posted December 21, 2012 - 06:52 PM
#45 pilot, fuel screw out 1/4
Went or 1/2hr ride, started to sputter on low end after 5 mins.
Tried fuel screw out 2 nd it died and I couldn't start it for 10 min.
Finally started and got going
While riding I pulled hot start and sputter was gone, clean off bottom.....but big POPs on decel as expected.
Soooooo do I need a smaller Pilot or bigger PAJ ?
Posted December 21, 2012 - 07:03 PM
Posted December 22, 2012 - 08:33 AM
If your bike runs better at part throttle wit the hot start, you need to either relace the needle jet emulsion tube because of wear or (...if it is in good shape) try a different needle leaner on the straight diameter (not clip position).
Posted December 22, 2012 - 06:58 PM
I removed PAJ as a test and it started really easily.
PAJ is #75 so I think a #100 or 110 would suit.
So I have EKP needle on #1 which I guess tells me it's still a bit rich.
What Is next leaner one? F..?
I've seen lots of mentions of EMN being successful.
Posted December 22, 2012 - 09:29 PM
Obdtm - stock
Obekp - current
OBEKQ - Try next (when I find a cheap one)
I appreciate you putting up with my ignorance.
Posted December 24, 2012 - 09:01 PM