Hello, John Talley here with Partzilla.com.
Today I'm going to walk you through the process to clean the carburetor on our 2005 Honda
CRF450R.
Pretty simple to do.
What I want to do is get the rear subsection out of the way and the seat, get the carb
off, take it over to the teardown table, get it broken down, and see just how bad it is
and get it cleaned back up.
So if you're ready, we can get started.
Alright guys, this is going to be a skill level two, so you really need to follow along
closely if you can.
Alright, let's talk about the tools you're going to need to get this done.
Not that long of a list.
Just need a flatblade, and then a Phillips screwdriver, a couple of different 3/8/ths
extensions, a good 3/8ths ratchet, an 8, 10, and a 12 socket, and then a 3 and a 4 Allen.
Beyond that, just a 10 and a 12mm wrench and then a good pair od needlenose pliers.
Now as far as the parts, that's really going to be determined by your machine.
This may be as simple as just using a can of carburetor cleaner, or you may beed to
get an entire rebuild kit.
But keep in mind, if you look at our exploded diagrams you can actually get each individual
piece inside of the carburetor, depending on what yours needs.
Plus, looking at the exploded diagrams gives you a much better idea of how everything is
going to come apart and more importantly, how it's all going to go back together.
So if you're ready, we'll head over to the machine and I'll show you how to do it.
Alright, you can probably get the carburetor out without pulling the seat and the rear
subframe.
I wouldn't recommend it because you'll be able to get it out, but good luck trying to
cram it back in there.
Especially with the rubber boots that are how many years old now?
Since this is a 2005?
They've been in there for a while.
Plus, it's not that tough to pull the rear subframe and get it out of the way.
The reason I'm having to go in and do this is we purchased this bike roughly four or
five months ago, and it was sitting up even prior to that, so it won't even start at this
point.
So we've got to get it cleaned up and see what's going on in there.
What I'm having to do now is I actually pull the boot on the intake back, because it's
hard as a brick.
So you really think you could get this carburetor in and out without pulling the rear section?
You're tougher than I am.
Alright, we already have our fuel shut off, so let's break this loose.
But to get to the connections for your throttle cable, let's go ahead and get the fuel tank
out of the way.
Once I have that clear then I can go in from the side and remove the cables.
Clean carburetor, step one: cut motorcycle in half.
Alright, now we have it somewhere where we can actually manage it.
So, let's go ahead and get that cover off, get our cables disconnected, and then we can
start cleaning her up.
I hope you were paying attention, it would be kinda tough to mix them up but of course
the longer one is going to go over to this side where it has to swing all the way around
that pulley.
Alright, one cable left, looks like it's for the hot start.
I think Honda knew it was so difficult to pull this carb out especially when you're
at the track trying to do jetting changes depending on what altitude you're racing at.
They actually leave a very large inspection hole right here to where you can go straight
to that main jet.
Makes life a lot easier.
Plus, you can look up in there just by loosening up the carburetor and tilting it.
Pull that and that'll give you an idea of what's going on.
If it's all green and furry, you've got a problem and it needs to come off.
And I'd already looked at this one, it looked okay, but this one wasn't starting so this
is where we needed to begin our elimination process.
So, we've got her off, let's head over to the teardown bench and start cleaning this
thing up and taking it apart.
Alright guys and girls, this is what they call a flat-slide carburetor.
You know most carburetors, the slide is usually cylindrical.
On this one it is actually a rectangle.
See how wide it is and flat it is here?
What I'm checking for here is just the movement plus see if there's any abnormal wear going
on in there, and actually this one seems to be in pretty good shape.
So for the most part we're going to be able to leave the top section alone because everything
feels like it's supposed to.
So what we're going to be mainly concerned with is what's going on in the float bowl,
you know, the main and the pilot jet.
But before I pull that apart let's use a little bit of our contact cleaner and just clean
up the outside because all this nastiness on the outside?
I don't want it to work its way on the inside.
It doesn't have to be perfect, just try to knock off some of this mess and then we're
going to pull the bottom of the float bowl.
If you don't wear glasses, put on a set of goggles because you do not want to get this
stuff to splash back into your eyes.
It does not feel good.
Let's get all these octopus hoses out of the way and get that float bowl off.
These are coming off pretty easy.
If yours are stuck, do yourself a favor and go pick up a hand impact.
Otherwise you're going to strip them out and that's going to make you have a very long
day.
Not too bad from what I can tell.
So, let's start pulling our jets out and see if one of them is stopped up.
Alright, so we've got our float bowl off, we've got our jets out, and what you're looking
at is your main jet, which is down on the end, then this is what they call and emulsion
tube, then you've got your pilot jet, and this mainly is concerned with the idle.
And then this other jet is actually for the choke circuit.
It actually brings it up through this particular jet.
So, first one I want to look at is the pilot.
I was expecting it to look a little green inside, so let's put thsat straw in there
and see if we can get it to squirt out the other end.
It didn't want to go at first put it evidently had something in there because not it blew
it out.
I would bet I can just see through it, and that's what I'm actually after.
Alright, if yours is stopped up, and a little bit of carb cleaner doesn't break it loose,
resist the temptation to cram a wire down in there.
Because if you do, you're going to scratch the bore on the inside and your jet is not
going to perform as it should.
Alright, since I've got her pulled apart, let's get a little compressed air and just
blow through this passage and make sure there's nothing blocking it.
didn't see anything fly out.
This is for the accelerator pump.
It's mechanical.
When you actually twist your throttle it pumps additional fuel straight through this passage.
Most carburetors are like a two stage, this carburetor is like four different stages.
Trying to get a smooth output all the way across RPM range.
If you want to get your air fuel mixture screw back in the place it started, what you want
to do is count your turns in and that's where you want to get it back to.
So this one is at there's one, one and a half.
So now you can go ahead and back it all the way out and what you're going to have in there
is a spring, a washer, and then a rubber O-ring.
Now the washer and the O-ring have decided to stay in there, let's see if we can knock
them out.
Alright, there is the washer I was talking about.
On the other side of that there should be an O-ring.
That little guy right there.
Tell you what, since we're there, and I've only looked at the outside of the slide, let's
go ahead and take a look at our main jet needle, because if its' worn in certain areas that
actually come down into the emultion tube, then it'll let fuel seep by and it won't run
correctly.
That needle actually looks to be in really good shape.
I don't see any grooves cut in it.
It looks like somebody has been into this carb before.
And I say that because this looks a little bit too clean in there, plus look at the color
difference between this and this.
Alright guys, this carburetor actually looks to be in really good shape, so what I'm going
to do now is go and start putting it back together.
Make sure if you go to clean this up with some carburetor cleaner, get your baffle plate
out of the way because it actually has an O-ring here and if you spray that with carburetor
cleaner it will deform the O-ring.
Alright now with everything out, what we want to do is just blow through all the passages
just to make sure nothing is in there.
Go through all your jets, float bowl, the float needle jet, and go over to that air
fuel and make sure it's clear.
Now here's where you need to be a little bit careful because this is counter-intuitive
and Iv'e done this wrong myself because it has that same shape to it.
It actually goes in there like this.
So make sure that hole is down at the bottom when you go to pop this back in there.
Alright, so let's go ahead and get her back in its bore.
When you're doing this make sure that you don't bend the needle.
Alright, when you get ready to release this, reach around this side and push that arm in
and that'll let it go back down.
Now we can get that set screw back in.
It's basically just going to be the opposite of what I did to pull it apart, so it's really
not that complicated.
Alright now, let's go ahead and get our air fuel screw back in there, because remember
it's spring first, then the washer, then this O-ring.
The best way to do this is hold it vertical and then guide it up in there.
Now remember, when you're setting the air fuel mixture screw, go all the way in and
we're going to back out one and a half.
So there's one, and a half.
Alright, let's go ahead and get our jets back in.
Our pilot.
Then our main.
Get our float back in.
We've inspected our little needle right there and it looks good.
I don't see any tears in it, so let's go ahead and lower it back in.
Just want to take a quick peek at our float level because what we're looking for is to
measure this distance, and the distance I'm talking about is from the top of the outer
edge of this float, which is measured from here to there.
So that needs to be 8 millimeters.
And how you find that is you look at it from the side and you bring the float in until
it just starts to push in on that plunger.
So that is approximately right there when that starts to happen.
We're going to set it to 8 millimeters just using a caliper.
Let's see where we are.
Very close to 8 millimeters.
So I don't think it's been moved, so it should be okay.
Alright, before we put the float bowl back on, I want to take a look at the accelerator
pump diaphragm and make sure it's okay.
Just pull those three screws and take a peek inside.
I don't see any nicks or cuts or anything else going wrong, so we can go ahead and put
her back together.
Make sure you didn't knock out that little O-ring right here.
Like I said, the float bowl level it looked okay, when I get it back on the machine later
when we actually start to run it, I mean if we have to go back and adjust it, pull the
carb to the side, drop off the float bowl, then make the necessary adjustment.
It looks to be within range, but we won't know that until we actually try to start it
later on in the series.
Everything feels good, let's go put it back on the bike.
This is actually a push-pull throttle, if you're curious why it had two cables coming
down.
Now remember just get those started because we still have to get that cover on there.
Do't tighten them down just yet.
Now we can go ahead and snug these down.
Before you tighten these down let's see if there's any play.
What I'm feeling for is to see if I can move this at all before it engages because I want
it to be instantaneous. and if it weren't you just take up your slack with that bolt.
Now, just need to wiggle her back down in there and get her pushed back on the intake.
There's a tab over here on the left on the intake boot you'll see where it lines up on
the carburetor to make sure you've got it in the right position.
Go ahead and tighten down that front clamp.
Alright, if you have not changed your spark plug in a while, now is the time to do that,
so if you've got an extra one laying around, I'd go ahead and swap it out if I were you.
Forgot to hook up the throttle position switch.Thought I could get to it.
Let's get our vents routed down, all basically going straight down in front of the shock
linkage.
Alright guys, that pretty much wraps this one up.
We'll listen, if you need any of the parts that we used to get yours back together why
don't you come see us at Partzilla.com and we can get you taken care of.
If you have any questions or comments, leave them in the section below and I'll do my best
to answer them.
And until next time we just want to say thanks for watching.