Brand New Bike Won't Run

Well I spent all day putting on new triple clamps, steering damper , handle bars, hand guards, and grips. I did all the free mods (cut throttle stop, pulled grey wire, uncorked the exhaust ), and now the thing won't start! It started and after letting it warm up I pushed the choke back in and bam! the bike just quit. It would only run with the choke on and the idle was get real high and then go back to normal. After letting it idle in my driveway for a few minutes the thing just quit and now it won't start!!! Will the WR not run unless a bigger main jet is installed? I can't believe I sold a perfect XR 650 that ran like a bat outta hell for a brand new bike I can't get started!!! AAAAAARGH! By the way, it's on '05 WR 450

hey seabass i would reconnect the grey wire and put the cork back in , im new to the 4stroke bikes but i try starting back at the begining i just bought a 04 wr450 only 90 miles on it so far , for the other stuff handle bars steering dampner shouldnt make a diff, did you take the slide out of the carb, i did and found out the hard way about the vacuum plate on the slide put it in upside down.

Did you turn your fuel on? Is there gas in the tank? :cry: You may have to rejet. Stock jetting is very lean. 48 pilot & 72 starter jet should help. Check that your fuel screw is not shut. It needs to be out about 2 turns. :cry:

Did you turn your fuel on? Is there gas in the tank? :cry: You may have to rejet. Stock jetting is very lean. 48 pilot & 72 starter jet should help. Check that your fuel screw is not shut. I need to be out about 2 turns. :cry:

Yes there's gas in the tank and yes the petcock is open. I put the muffler back in and got it started but it still just shuts off abruptly after I crack the throttle and let it return to idle. I haven't checked the fuel screw yet :cry:

I haven't checked the fuel screw yet :cry:

Bingo. My YZ had the screw 1/2 turn out from the factory and it had the same running (or lack of running) characteristics yours does...

I put the screw 2 1/2 turns out to start with and it would start and run fine, but it was still lean. Not running with the choke off is a tell-tale sign of being too lean on the pilot circuit. However, it should keep starting with the choke on. Be prepared for the possibility that you may have fouled a plug trying to start it.

Even with the fuel screw adjusted properly, you're probably still going to want to go up on the pilot jet most likely. Mine didn't run great until I did, and with colder weather coming you're going to need a bigger jet anyway.

You made the right choice getting the wr... As soon as you get the jetting right you'll agree I promise you. :cry:

Well i got my bike runnin again but only after I reinstalled the baffle in the exhaust. It starts just fine with the choke on and actually runs decent when I put the choke in, but it will NOT start when the motor is warm, the choke in, and usung the electric start. But it will start if I use the kickstarter, being so close to Halloween maybe it's posessed! I'll monkey with the jetting/ carb set up tomorrow

Thanks everyone who answered :cry:

Stop kidding yourself and buy some jets. It will not e-start with lean jetting. 48 pilot, 72 starter jet, and while you are at it put in a #40 leak jet. Needle in clip #5 from the top. 165 or 170 main. Stock jetting does not work unless you live at 10,000 feet. :cry:

As soon as I got mine home I took the end cap and baffle out of the stock exhaust and it WOULD NOT START AT ALL! It is so choked back it's not even funny. I will be putting a PC Type 496 or FMF Q on it. I am also taking the air injector off and capping it. The fittings are pressed into the head so it won't be like my 650 which required only a plate bolted over the hole. I heard throught the grapevine that "the grey wire is NOT an issue" on the '05" Because of this I have not clipped mine yet. Does ANYONE out there in WR land know about this for sure. I put in the YZ stop and cut the baffle out of the airbox as well as the pre-cut deals on the right side of the airbox. I will offer a crisp 20 dollar bill to anyone that can tell me what jetting to use with this set-up so I don't have to experiment too much!! SERIOUSLY :cry:

I had none of these problems on my 04 WR450 removed exhaust baffle, gray wire mod and nothing done do the carb and starts and runs very fast!

Seabass! I feel your pain!

My 03 WR450 is doing the EXACT same things that you are discribing. My bike is exactly like yours with the free mods and stock jetting. However, mine is not brand new. I have been racing it in Harescrambles all year (8 races) and it just recently decided to be a problem. (stall halfway through the last race)

Anyway, in the last month of working on it, this is what I've done.

New Sparkplug-> NO FIX

Rich Jetting-> NO FIX

Stock Jetting-> NO FIX

METICULOUS Carb cleaning 2 times-> NO FIX

Check Valve clearance. Good! -> Still NO FIX

Gave up, took it to dealer and trusted mechanic.

He cleaned the carb and replace AP diaphram. -> NO FIX

Check valves again. Good.

CHECK THE COMPRESSION! Way low! Running at 55 psi instead of 100+. So that's where I sit now. I have to take the head and cyclinder off to see what has happen. It could be that my valves or rings are not seating correctly or that I possible scored the piston. I don't know yet.

I soon as I find something, I post up. Please do likewise if you find out what's wrong with yours.

Tom E.

My 04 started within ten seconds. I had it delivered to me in the crate. I done mods periodically & it still started with the push of the button. I ride it like i stole it.

A few throttle twists depending on the temp....could be two...could be five & she fires right up. I've started it at 32 degrees F {0 celcius} With a push of the button.

Damn thing is rock solid. I ride this thing hard. I have tweaked the jetting on occassion, but it always started...not always ran perfect, but a jet tweak fixes that easily. Just gota have a basic underatnding of the throttle circuit & how it reacts to changes. Right now my bike is insane. This cool weather is wicked for riding.

As soon as I got mine home I took the end cap and baffle out of the stock exhaust and it WOULD NOT START AT ALL! It is so choked back it's not even funny. I will be putting a PC Type 496 or FMF Q on it. I am also taking the air injector off and capping it. The fittings are pressed into the head so it won't be like my 650 which required only a plate bolted over the hole. I heard throught the grapevine that "the grey wire is NOT an issue" on the '05" Because of this I have not clipped mine yet. Does ANYONE out there in WR land know about this for sure. I put in the YZ stop and cut the baffle out of the airbox as well as the pre-cut deals on the right side of the airbox. I will offer a crisp 20 dollar bill to anyone that can tell me what jetting to use with this set-up so I don't have to experiment too much!! SERIOUSLY :cry:

It looks like Indy450 has your jetting specs figured out. Send that man a crisp twenty dollah bill

Thanks Seabass! Please send my $20. directly to Blue Ribbon Coalition. :cry: We need to keep our riding areas open! :cry:

Indy you are the man. Now, translate that stuff to me. Is JD blue #5 a JD jetting kit? I changed the pilot and the main on my 650. I am not familiar with leak jets and where to position the clip etc. Thanks.

JD jetting kit available from our TT store has a red (summer needle) and a blue needle (colder weather). Clip #5 is the 5th clip position from the top of the needle. Leak jet is a small brass jet at the bottom of your float bowl which leaks of the ac pump squirt and reduces squirt volume. A smaller leak jet gives a richer squirt. :cry: Most of the FCR carbs for off road applications can be tuned this way.

Thanks again Indy. This forum is great! I will add $20 to my annual BRC donation.

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