Hello, John Talley here with partzilla.com. Today we're going to be working on our 2011
Polaris Sportsman 850. AS you can tell, we've already been working on it a little bit. What
we're going to do today now that we've got the engine out and somewhat cleaned up, we're
going to star pulling it down to see what's going on inside of this.
What was it doing? Well, it was still running, but it had low compression, especially on
one of the cylinders. Beyond that, it seemed to be pushing up a lot of oil through the
breather system you know, into the airbox. Something is going on in there. I'm not sure
what, but it'll probably be in the piston and rings, but we're going to start breaking
it apart and see what's what. So let's get started.
Alright guys, let's go over some of the tools you're going to need for the head inspection
project. One of the most important ones is a 14mm.
It needs to be pretty healthy and it also needs to be a 12-point. That's going to be
used to pull your head bolts. Other than that it's just going to be your
standard 3/8th sockets, a few different drives. At least will need an 8, 10, and 12mm. And
if you don't already have a full set of Allens you're going to need that as well, starting
off with two and going up to 10. I think we only used a couple of them on this project.
As always, you're going to need your little hammer, a screwdriver, a pick tool, magnet,
and then a couple of mark-sol pens so you can keep up with where the valves are inside
the head. Beyond that the only specialty tool you're
going to need is a valve spring compressor. It really doesn't matter which manufacturer
you want to go with. You just want to make sure that this area here is not bigger around
than the actual top of the valve spring holder. Alright, so let's get started on this. The
first thing that needs to come off is the valve cover. It's held on by six 8mm bolts.
So let's go ahead and get those out. As I've said before, I like these little impact
drivers, but they're great for taking things apart but I do not recommend them to use when
you're putting it back together because you're putting it back together because you're probably
going to strip it out, so Just be careful with these things when you use them.
Alright, interesting little note here. See that? That kind of milky white substance up
in there? That tells me that this oil may have been contaminated with water at some
point in time. That's what that indicates. This is also a little bit scary. See that
bolt right there? That is hand tight. It's kind of like doing an expedition: you
never know what you're going to find inside one of these machines when you start tearing
it apart. Alright guys, what we want to do here is go
ahead and bring around the cam shaft to top dead center. What we're going to be looking
for is a little protrusion that's going to come up vertical. Then we're going to turn
it another 60 degrees and that will relieve the tension on the rocker box.
Alright, so it's come past the vertical, and then there's a mark right here that should
be even with the head itself. Alright, at this point we don't have any tension
on the rocker box, but what we do need to do next is go ahead and pull the tensioner
on the cam chain itself. Once we get that, that will loosen up the
tension on the sprocket and the chain. We can go ahead and remove our rocker box and
get our chain off the sprocket. You want to notice, on the tensioner, it's
actually directional. It has a little stamp that says "top."
I don't think it's possible to actually install it incorrectly, but they're just making sure.
Just a couple of 8mm bolts. There we go.
Alright. Let's go ahead and get those rocker box bolts out now.
Alright, everything is looking pretty good in here. I still don't like the fact that
there's so much of that milky colored oil in here. Maybe whatever caused that will come
to light as we go along. I don't see any abnormal wear so far, which
is a good thing. Alright, let's go ahead and get that cam shaft
bolt out so we can get this chain off. Alright, at this point if you were not going
to pull the head off, which I am, I would suggest putting a wire on this chain to hold
it up. But since I know I'm going further down into the engine, I'm just going to go
ahead and let it drop. Next, we neet to pull the six main head bolts
up top, and then you've got two 8mms over here. Don't forget about those. And then she
should just lift off. Alright, before I start pulling this apart,
like I said, you want to get those two 8mms out of the way. And there's a pattern that
you need to follow up here.You're going to do these about an eighth inch of a turn on
each one and the pattern is six, five, four, three, two, one.
You just want to keep repeating that until all of the bolts are completely loose.
This is a 14mm socket that you're going to need. You need to make sure that it has 12
point because a regular six point isn't going to work.
So a 12-point on there. It takes a fair amount of torque to get these things going so you
may have to have somebody help you hold the engine with a breaker bar to get these things
started. Alright guys, we got everything loosened up
and backed out. Boy wasn't that fun? I know that tightening these things down you
take them to like 43.5 lbs and then you put another 90 degrees on it. Where does that
end up? My best guess is probably at least 100 ft-lbs and it sure felt it when we were
pulling this thing apart. It took three of us to hold it down. So good luck with that.
Alright, go ahead and get these 8mms out of the way, remove all of these.
I'm about to forget something. Don't forget to disconnect this little hose on the backside
that goes up to the thermostat. Just like that.
Off she comes. Alright guys, here's what I'm seeing so far:
nothing really out of whack on the heads. A fairly good burn pattern, a little bit of
carbon buildup, nothing that extreme. I do want to go ahead and pull the valves out,
take a look at the seats, see if they're seated properly.
What we want to do is go ahead and number all of the valves. That way, if we decide
to reuse them-- which I'm 99 percent sure we will be-- they go back in the same place.
That way we don't have to recut seats or anything like that.
So you want to get a mark-sol or a Sharpie that is not black. I'm using a silver one
here. So go ahead and get those marked. Set it up in there where your valve is sitting
directly down on this point. This little cup will hold it in place.
Reach in there with a little magnet. Pow. Out comes that keeper.
What I'm doing now is just pulling the valve in a little bit to see how much play there
is in there. Honestly, that feels perfect. Nice and smooth,
hardly any play at all and that seal at the very top still feels like its pliable.
Looking at the valve I don't see any score marks. Extremely smooth. I don't feel any
lips, any edges right here. You know the valve's moving in and out on the valve guide itself
and if it were really worn you'd feel a lip or an edge in one of those two spots and it's
nice and smooth all the way across. Next thing we're looking at is the actual
seat of the valve or the valve face. You can see where it's riding in the seat of the head.
I don't see anywhere where it's you know, blowing past it so I'm betting these are sealed
up pretty well. I don't feel any edge on there. Same story on the valve seat. See that edge
all the way around or that circle all the way around is even. There's no carbon or buildup
or anything that I can see to where it was not sealed up properly. So this head is in
good shape, just judging by this one valve. I'm not being lazy here, but if this looks
this good, chances are the rest of them are going to look just like that.
I mean that was an exhaust-- or an intake valve that I just pulled. We'll pull just
one of the exhaust just for fun. Jump over to the other cylinder, take a look at it.
If it looks that good, I'm just going to put it back together and I think she'll be good
to go. The exhaust is telling the same story. And
as we saw on the intake side. A little carbon buildup, nothing that dramatic.
The seat looks even all the way around, no funny wear or marks anywhere. So, this head
looks to be in good shape. So what I'm going to do is put those valves
back in and then get back up to the engine and stat pulling it apart.
Alright guys, well the valve's back in. This one is pretty much ready to go. I'm just going
to go back and clean it up a little bit more and it will be ready to go back on the engine.
I'll get some of this residual sludge. There isn't a whole lot of it in there but I want
to get it back clean before we put it back on the engine.
Listen, this part of the diagnosis of the engine is complete, so this piece is ready
to go back. What we are going to do is go further into the engine so that means we're
going to split it in half, take a look at those pistons and rings, and the cylinder
bore and see how that looks. So you need to come back and follow up on
our next video and find out what's really going on with this machine.
Listen, we appreciate you watching and we'll see you in the next video.
Thanks.