2004 WR450 won't fire - sat in storage five years

[KGSloan]

yes, i'm learning all about these things - a whole new world. it's been a fun, and sometimes frustrating, process.

i've got a couple pics to show you guys, i had a couple of points where old brittle parts didn't come off and now i've got to make do and want some second (and third) opinions...

first pic, i broke part of the casting in the carb around the starter jet. it's all below the threads and doesn't effect insertion/removal of the starter jet, so i'm thinking it's ok. what do you all think? I have the broken piece if i need to worry about repairs...

it is very clean though ?

and the next two pics have to do with the vent lines (which were dry/cracking). I broke the plastic 'T' fiting that comes off the carb above the choke as i removed the lines for the carb dip. You cannot buy this fitting from yamaha by itself (sold with carb). The picture below has the fitting partially inserted for visual reference

So, I have spent some time today going by hardware stores and finally found the following to use to relace the fitting at O'Rielly's

What do you guys think?

I also plan to replace the carb vent lines with new...

[ronbuell]

You could use a little JB weld and glue it back, but if it was mine, I'd leave it off and try it like it is. If it works, forget about it. Vent lines, replace.

[miweber929]

There are much smarter people on here than me, but I think that may be an issue as I think it's longer specifically to be always completely submerged in gas and if the corner is broken like that it will suck air.

Assuming you used a too large screwdriver to get it out? JB Weld may hold, but I'd look at a weld or a used body. Like someone mentioned, though, try it and see.

I had an old 84 XR250 Honda with the twin carb setup. Someone had rebuilt the carbs at some point and put the wrong floatbowl and slow jet in there and the bike ran and drove sort of fine on smooth trails. But if you get moving around it would hesitate and I fell a couple time when the bike stalled. Took a VERY astute Honda service guy to find it.

And as far as the T fitting, look around some more and find a brass one to fit. If Yamaha could have gotten away with using a plastic on from the factory, they would have. My belief is it's brass for a reason. The fittings are out there.

[FORMA MOTO]

JB weld will work just fine.

Another plastic T will work fine too.

[KGSloan]

it seems to me like replacing the broken plastic tee with another plastic tee should be just fine...

i am concerned about the jet, somewhat...the plastic spacer goes up to all three of the jets, what is the purpose of this spacer? i guess it's to keep fuel in and around the jets, but it's not sealed against them or anything so i don't know. I will probably try to jb weld the broken piece back on.

who knows, i may be buying a new carb for this thing - at least i'll know how it works though ?

[ronbuell]

The plastic part you're talking about is what the book calls a plate. The purpose is to keep fuel around the jets from foaming or bubbling during rides over ruff ground. It doesn't fit up tight against the body. On some bikes, the bowl is what holds it on. Very simple solution to a frustrating problem.

[KGSloan]

The plastic part you're talking about is what the book calls a plate. The purpose is to keep fuel around the jets from foaming or bubbling during rides over ruff ground. It doesn't fit up tight against the body. On some bikes, the bowl is what holds it on. Very simple solution to a frustrating problem.

thank you kind sir ?:thumbsup:

[FORMA MOTO]

it seems to me like replacing the broken plastic tee with another plastic tee should be just fine...

i am concerned about the jet, somewhat...the plastic spacer goes up to all three of the jets, what is the purpose of this spacer? i guess it's to keep fuel in and around the jets, but it's not sealed against them or anything so i don't know. I will probably try to jb weld the broken piece back on.

who knows, i may be buying a new carb for this thing - at least i'll know how it works though ?

That's an 'anti-cavitation cup' that is called a 'plate' in the parts book. It's there to keep air out of the jets.

[Shred Jesse]

...and as said before it's to deal with sloshing gasoline while riding over rough terrain.

It may not be a bad idea to try and build that pilot jet surround back up. It simply may not be doable however.

I'm wonder what it would take to attach the more advanced WR450f carb onto the WR400.

[MaxPower]

since you have the carb off, change out the piece of plastic where the hot start cable fits into the top of the carb. I think a 12mm wrench fits on it. It was years ago when I changed mine.

It snaps easy when you are trying to fit the carb back in the bike and you bike runs lean. Mine is red aluminum and I think it came from pro circuit

[KGSloan]

It may not be a bad idea to try and build that pilot jet surround back up. It simply may not be doable however.

since i still had the broken piece i was able to put it back in with jb weld and really build the area up nicely while leaving the jet passage clean. i'll post a pic, but i think it's just as good as it could be ?

as soon as the new float bowl o-ring comes in (hoping tuesday) i hope to get this thing fired up and running for the first time in many moons

[crash279]

Needle valve that is connected to the float? If so, that does need to come out. When you put that carb in the solvent it needs to be completely stripped. Otherwise it will get really expensive.

[KGSloan]

so I got this beast up and running last night....was a good feeling that it worked ?

it was a bear to get running, I had to roll it down my drive way and pop the clutch...once warm it runs pretty smooth and idles nicely, starts no problem without the choke. To start it today at lunch i had to again roll it down my driveway however...

Here are my current issues with the carb tuning:

1) will not start when cold without pushing it - is this pilot screw adjustment?

2) hesitates a little at low rpm when going from low throttle to slightly more throttle

I left the bike 100% stock because I just wanted to get it up and running and make sure everything was right...it sure does feel choked on the top end, and, maybe some of that's tuning.

[Shred Jesse]

it's quite possibly way too lean.

What is your exhaust setup? Depending on this, we may be able to give you some factory tuning specs to start with and base everything from.

[KGSloan]

it's quite possibly way too lean.

What is your exhaust setup? Depending on this, we may be able to give you some factory tuning specs to start with and base everything from.

100% stock, nothing on this bike has been changed from factory delivery. I just want to make sure i've got it all ironed out before I put exhaust, grey wire, throttle stop, etc. on it. Thanks! :up

it does seem to run well once warm, but I really have no basis for comparison....

[KGSloan]

well, had a little more time after work to play with it...

it's a bear to start regardles, hot or cold.

tomorrow I will start with the following:

1) adjust TPS (removed it during the carb bath and need to check)

2) adjust the fuel screw per the procedure in the sticky at the top of the forum

something cleary isn't right with the tuning on this carb right now, it's very clean so I don't believe it is coming from clogged jets. I don't know what else to look for and adjust for a hard to start bike, all the reserch i've done on here talks about adjusting the fuel screw so here we go!

also, i've been reading the tuning section of the manual and it dawns on me that I don't know what position i put the clip in on the jet needle. I didn't realise I should be paying attention to that, so I may rip it all apart again anyway ? I'm going to figure this out at some point man being a newb is tough

Edited December 4, 2010 by KGSloan

[chrispy1202]

Once the TPS is set correctly, then you can move on to the jetting. If the jetting is off, your bike will run like a bag of crap. Proper main and pilot jet, along with correct clip position on the needle will get this baby running smooth. Then a bit of final adjusting to the air/fuel mixture screw and you should be set. The jetting may have been wrong for the previous owner, so check to see if it's the right stuff right away. If you can afford to get a JD jet kit i would highly reccomend this. They tell you according to the elevation and temperature where you live, which needle to run and in which slot to position the clip. Done. These bikes are very choked up in stock form, but can put out some great power with only a few fairly cheap mods. I put on a YZ450 exhaust, did the throttle screw, the JD jet kit and an adjustable air/fuel mixture screw for around $300 and it rocks.

Cheers

Chris.

Edited December 5, 2010 by chrispy1202
need it

[travertt]

I too have an '04 WR450F....although mine has a different exhaust from what I see in your picture.

I won't comment on your carb problems...you are already getting lots of good advice from what I can see...but I will suggest the following..

If you are going to ride this bike any where near its potential, and based on the picture you first posted...you should (must) install a proper skid plate, bark busters and top quality rad guards. After that you may want to consider disc protectors and case protectors. Its an 04...I wouldn't bother with frame protectors...strictly cosmetic.

Oh yeah...since you say you are new to dirt biking....make sure you protect your body like you protect your bike. Do not ride this thing without ALL the protective gear...best $$ you'll ever spend!! This is a serious machine when opened up and ready to go.

Have a blast!

[Shred Jesse]

Oh yeah...since you say you are new to dirt biking....make sure you protect your body like you protect your bike. Do not ride this thing without ALL the protective gear...best $$ you'll ever spend!! This is a serious machine when opened up and ready to go.

+1

All the slickest most comfortable bad ass gear still comes in at far less money than an ambulance ride and a hospital bill.

[FORMA MOTO]

100% stock, nothing on this bike has been changed from factory delivery. I just want to make sure i've got it all ironed out before I put exhaust, grey wire, throttle stop, etc. on it. Thanks! :up

it does seem to run well once warm, but I really have no basis for comparison....

This is your problem. It runs terrible right from the factory. Don't second guess the decades of experience here on the forum. Unless you feeled compelled to go through a extremely long and frustrating learning curve.

Follow the sticky's at the top of the forum, and uncork and rejet.