ready to throw my 03 450 in a dumpster

and go to the Honda shop. i cannot get this damn thing to run right. It is in the 50's here now and my jetting is all stock aside from the needle which is one position leaner. The end of the pipe is sooty black. the plug was absolutly sooty black as a dirty chimney. the bike pops and coughs and on the gas. It pulls hard but it is not running right....I am so annoyed with this bike. it has VERY low hrs on it, maybe 15 hrs or so.

has anyone got any ideas? I already unplugged my TPS and it was the same. God what i would give for another CRF

sometimes the weather throws the jetting off so it doesnt matter if its stock alot of times they are set to run at certain temps so you might have to go in and change it or try and richin it up a little bit

Sounds like you're lean and/or running oxygenated fuel to me. Don't forget 4-strokes will make black soot when they're running lean as well as rich. Actually with pump gas you may get a sooty tail pipe even when it's running spot on. Try adjusting the jetting not by now the plug and pipe look, but by how it runs. If it's popping a lot then that is a good indication that you may be lean. Actually if your temps are in the 50's (assuming you're close to sea level) and you're LEANER than stock then I'll bet $5 that you're too lean. If you must throw it in the dumpster, please let me know which dumpster!

It's not a matter of what color the bike have to be able to trouble shoot. Unfortunately carb tuning is not easy. As was mentioned you have to know what kind of gas your running, the weather conditions etc. I saw no mention of the adjusting the fuel screw.

due to the accelerator pump on the bikes they will always have soot. Consider just how much gas it squirts and how little of it burns. Dont let it throw you.

Cold air means denser air. That means more oxygen to ignite more fuel. so you have to supply more fuel when it's cold. oxygenated fuel only exaggerates the need for richer jetting.

Make sure the air jets in front of the carb are not blocked up with filter oil though. Then start jetting bigger with the main first then the pilot then the needle for the smoothest transition between the two.

Ya, what dumpster? I'll tow it home with my CRF :cry:

Before throwing it in the dumpster, please inform me where your at and what dumpster you threw it in.. Thank you. :cry:

Sorry, just had to do it,, ask here and someone will help, either here or in the jetting section..

If all this started after you changed the needle position, make sure the slide is in the carb with the cutaway on the bottom, facing the airbox.

Thanks for all the suggestions, but I have already tried everything easy. it ran terrible right from the first time I rode it. Great power, yes, but the popping and gurgling in the midrange is very annoying. I have tried larger mains with stock needle, all kinds of pilot scrtew settings, ridden in different temperatures, etc. The plug looks like someone spray painted it black then dipped it in ashes... It is def. not lean.

But how can it be choking on too much fuel when I am already leaner than stock? I dont think it is an accelerator pump issue because it responds well when quickly revved in neutral- no bog like my WR

I am just flustered because I have never had a four stroke that even cared much at all about temp, fuel choice or required much jetting at all. This bike will not run right with ANY setting as far as I can tell

somebody buy this bike from me: it has such low hours, the air filter has not even been dirtied yet- ever

I don't think anyone is saying that it is running too rich, or "choking on fuel". They are saying that it is too lean, and the colder air is making it even more lean. Richen it up, give it more fuel, and see if it improves.

Check for air leaks at the header, both ends! I had a problem just like that and I went through hell trying to find it, here it was the pilot jet, it was one size to big. It was amazing what one jet size did! :cry:

Great power, yes, but the popping and gurgling in the midrange is very annoying.

you said earlier that you leaned the needle out a notch. try lowering the clip 1 or 2 positions (do it a position at a time). midrange is the needle.

Well good luck with the CRF, it has the same carb that the yz. Tuning the FCR is pretty complicated, maybe try taking it to a good shop and have it jetted.

What is your altitude? I run close to stock jetting up to 1500/2000 ft - put the clip on 4th position - Cold temps will affect the way it runs - usually causing leaner condition - I will adj fuel screw but some popping in low 50's is expected - are you running stock pipe of aftermarket? Aftermarket may be leaking at mid joint.

Below 50 they all run like crap...fuel injection will cure that.

Where is the dumpster - I can use some spares :cry:

I WILL TRADE YOU A YZ426 2002 for it. I love my crf, would love to have another one. Send me a line if you are interested. The YZ is a great bike I just like Honda a lot more.

heres a link to show you what im talkinking about

make sure you if you did have the slide all the way out of the carb,to make sure you installed the little plate the right way on the slide

it makes one run really bad and have multiple symptoms of lean and rich

Rather than throw it out, ship that sucker to me and I'll pay the shipping!

you're absolutely right those yamaha's are crap and the honda's are the way to go. much did you want for the piece of crap?

Don't all the new thumper pretty much run the same carb? Won't he have the same problesm with the CRF as well?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now