Hello, John Talley here with Partzilla.com. Welcome back to our third
installment of our top end project on our TRX 400EX. What I've got laid out on
the table is our cylinder which we just picked up from the machine shop. Our head,
which we're going to go ahead and replace the seals on it since we're here.
Got the valves out in front and a couple of minutes, I'm gonna take them over to
the grinder and actually wire brush them off. They got a fair amount of carbon on
them and we need to get that cleaned off. Plus we have all these parts that we're
going to be putting in the machine. We've got our piston, we've got our rings, a new
wrist pin, the the valve stem seals, our base o ring, which actually goes
on the bottom of this cylinder right here. And then we've got a complete
gasket set that has our base gasket, our head gasket, and all the associated
O-rings and seals that we're going to need to get it reassembled. So let's grab
those valves, run over there, getting them cleaned up, and then we'll start putting
her back together. Alright guys, when you're using the
wire brush to clean this off, remember it's spinning it over 3,500 rpms. It takes
a light touch but don't let it grab it out of your hands. Now I'm just using
some contact cleaner to clean off the just some residual left by the of the
head gasket. Alright we've got our valves cleaned up, we've got the head
cleaned up, use that wire brush just to clean out the combustion chamber just a
little bit. And what we're going to do next is going to go ahead and replace
all of the seals. I mean, is it really necessary? Nah, they're in decent shape
but keep in mind that this machine is 10 years old or coming up on it. So it's an
inexpensive part where all we're down this far into it. Let's go ahead and get
them replaced. Make sure you get that little ring at the bottom.
Here's a little trick to getting the new ones back on. What I'm using is just an
11 millimeter socket which this just happens to fit right inside of. So we'll
use that to push them on. Make sure when you're putting these on to keep a
lookout for that little snap ring. See right here? This one has actually gotten
pushed down so we need to make sure that that ring's up on the rubber. Alright
we've got our valve seals in, all four of them. The combustion chamber has been
cleaned out a little bit, so it's time to go in and start getting the valves back
in. What you want to do is just get a little bit of oil on the stem. Slide her
back in. Number one, number one.
Press the spring back down about right there. It can be a little tricky getting
these keepers back in. Let it slide over to the-- or tilt over to the side, pop in
the first one, and then seat it down. Now you just need to rock it back the other
direction, grab the second keeper, drop it in place, and then push it in with your
finger. Release the tension on the spring and they'll lock down on the valve stem.
Okay with our valves back in, we need to address our piston. And what I want to
show you is the orientation that we need to put the rings in. Basically you've got
three different rings. Well, the oil ring is made up of a spacer and a lower and
upper ring but I call them just one ring. But they need to be oriented in a more
or less a triangle configuration, with your top ring right here. That's where
the gap needs to be. Your second ring is 120 degrees away, so it's going to end up
being about right here. And then your oil rings, you're going to have the spacer
right there in the center, and then about 20 millimeters away you'll have the
bottom ring, the keeper, and then another 20 millimeters this direction. So that's
the general orientation that you're going to have. The rings are actually
marked with a number, in this case it's N-25, and that will show you the top
half of the ring. And the way you tell the the top ring from the the second
ring is the top ring, on the outside edge, you're going to be able to see where
it's chamfered on either side, so it kind of has a dome shape to it.
Your second ring, looking at it from outside, from the top, it's going to look
like it has an angle right here where it kicks out it's wider toward the
bottom of the ring than on the top of the ring. So that's the way it's going to
need to go together. Alright so let's start putting it together. Alright you want
to start with your old ring first, and it's actually made up of those three
different pieces. Put your spacer in first then the bottom oil ring then the
top oil ring. Then you can go and put in your second ring. And then finish it off
with the top one. Once you get them in place, then you want to spin them in to
that orientation where there are 120 degrees away from each. This point you
can go ahead and put in one of your circlips.
Make sure the end of it is not in this section right here. You want it facing
away. Alright go ahead and start your wrist pin on the other end. Lower it down
onto the connector rod. Make sure it's lined up and just push her in make sure
it bottoms out against the other clip. After that, you can go ahead and put in
the other snap ring on the other side. Make sure you clean off all the residual
gasket material on the base gasket. At this point, you're safe to go ahead and
remove your shop towels.
Get your base gasket put on, feed your timing chain up through it, very careful
not to rip it as it is somewhat fragile.
Alright there's one additional seal that does not come with the gasket
set from Honda. It's actually an o-ring that goes on the very base of the
cylinder. I mean there's a base gasket but you also have the seal.
She just slides in to this little groove right down on the bottom and then we'll
get the cylinder pushed down on top of her, alright? Alright, before you put
the cylinder on, you want to make sure you've got a little bit of oil around
the rings and on the piston just to get it started up in there. Go ahead and oil down
the bore as well. Line it up, and let's start feeding those rings up into the
bore. You can use the tips of your fingers just to compress it on either
side and then start working it up into the bore. Go ahead and push it all the way
down, line up on your dowels, pull your chain all the way up through. Get it out
of the way. And seat it down. Alright, here we're setting our torque wrench and
getting them torque down. I usually start off by just putting around 10 to 15
pounds in a crisscross pattern before I take it out to the the final torque of
32 foot-pounds. Once again, doing it in a crisscross pattern. Now you need to go
ahead and install your timing chain guide. Make sure it engages on the bottom.
You can rock it back and forth and if it flips up, you don't have it engaged
properly. Very important here don't forget your two dowels for the
head. Go ahead and feed your chain through the head gasket.
Now with your head in place, go ahead and feed the chain up through the head and
lower it down, making sure it's aligned on those two dowels we just installed.
It'll slide right into place. Shouldn't rock at all. Don't forget to
put your washers. You'll have four. And be extra careful when you're putting in the
one next to the timing chain. You don't want to drop that and have it go down
into the engine. Alright, these are about the same as the the base cylinder.
You want to go ahead and just do it around ten to fifteen pounds to begin
with. And they actually have the same torque as the cylinder bolts, which is 32
foot-pounds. Alright before you put your camshaft in, you need to make sure
that you put in the spring and the plunger for the decompression mechanism
on the camshaft itself. Be very careful. Once again this is right next to the
engine where it would just drop straight down in there. And now you can set your
camshaft in place with your timing chain just draped over the top of it. Next you
can just tilt it up and slide on the timing gear itself. From here, you can
slide the chain over the sprocket and then bring the sprocket back up onto the
camshaft where the bolts are going to feed through. Need to make sure that the
cam lobes are facing down. Next you can install the two dowels on either end of
the camshaft itself. Once they're in place, you can go and install the
camshaft bolts. Start with the top. Once we're done with that,
we'll rotate it 180 degrees and grab the one at the bottom.
Don't forget those two base bolts for the cylinder. Just a couple of eight
millimeters on the side. Next we need to go ahead and prep our camshaft chain
tensioner. All you need to do this is just a just a flat blade screwdriver.
Turn counterclockwise to bring the piston all the way back. Spring-loaded. If
you carefully remove the the screwdriver it will actually sit in place. Get that
into the the cylinder. Don't forget the gasket. Then install those two eight
millimeter bolts. At that point all you need to do is just tap it and that will
release the spring and it will put the appropriate amount of tension on the
chain itself. Next we need to just install our valve cover gasket. Then we
just want to use a little bit of oil, put it over the cam lobes, just to make sure
that they're there submerged and all on startup. After that we can just put it on
the head cover with all those little 8-millimeter bolts all over the place.
Once you get all of those tightened down then we need to put in the main motor
mount for the for the head at least on top of the machine with those two large
spacers. At this point we need to go ahead and adjust our valves. Remember
this: point one millimeters on the intake, 0.12 on the exhaust. Once they're
adjusted go ahead and put on our inspection caps. Now we can start working
on the exhaust. Put in our new crush washers that seal up the exhaust
manifold and start working that exhaust back up in there. Bring up our two
flanges.
Start tightening down those 12 millimeter bolts. Next just slide the the
slip-on exhaust back on. Don't forget that bolt down at the bottom. And then
retighten your clamp right there. Reinstall your inspection plugs for the
crankshaft where you found top dead center. Now we can just slide the intake
back on. Retighten the clamp on the intake boot on the front and the back of
the carburetor. Then you've got this three ten millimeter bolts that hold the
airbox in place. Two up front where these two clamps are, and then the one in the
back. Don't forget that plastic shield that goes up under the fuel tank-- held in
place by a couple of ten millimeter bolts. Next route your fuel line up from
the carb through this little rubber flap. Then lay in the fuel tank. Hook up your
fuel hose, turn the fuel on. Alright guys, we've got everything buttoned back
together and now comes the moment of truth. So let's fire it up see what
happens.
Liking that.
Music to my ears Alright to wrap this up, all we need to
do is reinstall the plastics and go through the break-in procedure. The first
50 miles is going to be really important for this, so you want to make sure you
don't run it wide open. You want to keep varying your speed starting and stopping
a lot because you're trying to get the rings to seat back in properly. Listen if
you need any of the parts that I used for this this rebuild, come see us at
Partzilla.com. If you have any questions, if there's anything that you couldn't
see that I wasn't working on, just leaving a comment below and I'll do my
best to answer you. Listen we really appreciate you watching and we'll see
you next time. Thank you