Hi. John Talley here with Partzilla.com. Welcome to our second part of a three
part series we're doing on our 2007 honda TRX 400EX. As you can see I've got
the the top end laid out on our table and we're going to start investigating,
trying to locate where this particular machine was burning a little bit of oil.
We're going to start by taking a look at our camshaft. Looking at the lobes, making
sure there's no scoring marks. All of that really looks good by the way. Going
to look at our our main cover. See if there's any scores inside here. Any
sloppiness or play and the rocker arms. All that looks good. What we're going to
do next is go ahead and take our head, we're going to put it up inside this
where this vise is holding our valve spring compressor we're going to go and
pull those valves out and take a look at the seats and as well the seals on the
the valve stems. As you can see each valve has a little bit of an indentation
in the middle of it. Where that's going to rest is right here, so get that lined
up. And we're gonna compress that spring. What that's going to do is bring out the keepers on
either side of the valve. Just use use your magnet, reach in there and grab them like
that.
Now just release the tension on the spring.
You actually have an inner spring and outer spring and then this top section
which holds your keepers. Alright, with that, just go ahead and push the valve, pull it
straight through. What we're looking for here is anywhere on the valve itself
that actually looks good. Kind of put the valve in, make sure it isn't rocking
around too much. I'm just kind of wiggling it back and forth. All that
feels good. Then you're looking at this section right here, which represents
where that valve is actually seating or sealing up into that seat. And I don't
see any points where it's not sealing up pretty well. So that valve really looks
to be in pretty good shape. What we're going to do is go ahead and pull off, you
know, all four of them and take a look at the other, other seats and valves as well.
Another thing we want to check is the the seal on the valve stem. Make sure
that isn't real brittle. That one actually looks to be in pretty decent shape, but
if I'm this far into an engine I'm going to go ahead and replace those seals. So
I'm going to go ahead and repeat this process,
go ahead and break the head all the way down. We'll take an overall look at it
and then go from there. Something I should mention before I pull the rest of
these valves out. They are looking so good I can go ahead and pretty much
assure you that I'm going to end up putting these right back into the head.
So, before I do, before I pull them out, let's go and get them numbered. That way
they can go back you know to their home base, so to
speak. So let's make a little mark here and here. Of course your exhaust and your
intake, different size. So you don't need to go one, two, three, four. You can just go
one, two, one, two. Alright with that done, we're going to go ahead and get the rest
of them pulled out. Looking at all the valve seals, they do look good. Like I
said, you don't go this far into an engine and not replace something as
simple as that, because it is a 2007 and that means she's been sitting around for
about, coming up on ten years. And it's not when, it's not if, it's when these are
going to fail. So let's go ahead and renew them when we put it back together.
I think we can eliminate them as being the culprit of our problem. What we are
going to do, when we go to reassemble it, is going to take a wire brush and clean
out the combustion chamber and then also take each valve over to our wire brush
wheel and clean off the especially the backside of the surfaces. Because that
carbon that builds up right there? That actually impedes the the air flow either
for the intake or the exhaust. Alright let's take a look at our cylinder. I
don't see any scoring. Everything still looks pretty much the way it should.
I feel just a little bit of a lip right at the bottom so that tells me I'm
probably going to need to take a look at that oil ring. Because I mean everything
up top looks good. I don't feel any edge on the on the top of the bore. So
start looking at our rings. What I'm looking for here is any uneven surface
that would make it like kind of like an egg. All that looks good. What we're going to
do is we're going to pull each ring then I'll come back to this ring later. I'm
actually going to put it inside the cylinder and measure what they call the
ring gap, and what that'll be is this has to be a certain thickness here or width.
And if it exceeds that, that tells you that either the ring and/or the cylinder
is worn. But I'm just not seeing that, but the measurements will tell the tale.
Do our second ring.
Same story.
Let's get down to our oil rings. I'm betting this is where we're going to
find a little bit of a problem. These things are so thin, what you actually
have there are three different pieces. Got a top ring a bottom ring and then
that little inner ring will be our design huh? Been around for a long time
though. Alright looking at our piston, what concerns me is the amount of oil. It's
just wet on the top of the crown, and it shouldn't be like that. So there's-- oil
has got to be getting past our rings somewhere because it is just sopped in
here. I'm putting that aside, looking at our oil rings. Alright come on in here
look at this. this is one of our oil rings. This is actually I think the
bottom one. As you can see that is so thin right there compared to this
side, which is probably twice the thickness as this is. So it is worn kind
of like a an egg here and here, while remaining true on the other ends. So how
we're going to fix this? Well we're going to go ahead and move up
to a plus one piston which is going to increase the bore of the machine by just
one size. Go and replace the piston, the rings, and we'll take all that to the
machine shop with our existing cylinder and have them board out to match. So
that'll be the next move we need to make. Listen, you definitely want to find a
good machine shop to do your work. I use hiTEC and he's one of the best out
there. This is Tim Kremens and he's been doing this for 30 plus years and he is
definitely the man. What he's doing now is just boring the
cylinder first, and like I said we're only going one size over, so not taking a
lot of material. Next he put it in the honing machine which actually cross
hatches everything. And now it's complete. Really looks good in there, nice smooth
bore. Let's head back to the shop with our piston and get it put back together.
So I think that's going to be our smoking gun guys. Listen, I appreciate you
watching. Give me a little bit more time and join me in video number three and
we'll get it put back together. Thank you.