Hello, John Talley here with partzilla.com, and welcome back to our engine rebuild on
our 2011 Polaris Sportsman 850. You know, we've already got the bottom end
assembled, we've got all our gasket services cleaned off and ready to go and what we're
going to do today is go ahead and get the head back on there and get it timed properly.
So, with that being said, let's go ahead and get this thing spun around, get my gaskets
here set up for the machine and get it put back together.
So let's get started. In the previous video I'd already torqued
down this bolt. That was a mistake actually because we should have left it out. Because
what we want to verify is that we're on a compression stroke and we want the cotter
pin to be facing up-- which it is. So we were actually good to go on that.
Go ahead and reinstall that flywheel bolt and get it torqued back down to spec.
Keep in mind that is a reverse thread. Alright, with that re-torqued, we can go ahead
and pull our chain up and we're going to put that other chain guide in and then get our
head set on. You want to make sure that these surfaces are completely clean.You don't want
to leave any fingerprints even on your gasket when you're getting this put back together.
Alright, with our chain pulled up, we're going to go ahead and get our chain guide in there.
You want to make sure that that hook goes on the edge just like that.
If it weren't hooked it would kick out right now.
Alright, next we're going to find top dead center. Where the two case halves meet, that
match line is going to line up on the flywheel where it says T-D-C. Right here.
Alright, next, you want to make sure that your dowel pins are in place, the surface
is clean. Just grab your gasket by the edges like so.
Alright, with the head in place for the head bolts we just want to oil the end of the threads.
Everything is just hand-tight right now and the sequence that we're going to need to get
these tightened down is going to be like this: one, two, three, four, five, six. And this
is actually a two-stage process to get it torqued down. The first torque setting is
going to be 43.5 foot-pounds. One you do it through that sequence, then the next sequence
is to tighten each one 90 degrees in the same pattern.
Alright guys, we've got our head torqued down and the next thing we need to do now is go
ahead and install our cam shaft and the rocker box.
Alright, when you put in the cam shaft you want to make sure that you go ahead and put
a little bit of oil on the lobes and the journals. We definitely want that to be lubricated when
it's starting up for the first time. Alright, you want to verify that your crank
shaft is still at top dead center and then initially we just want the cam shaft with
that little dowel pin facing up. Then we can go ahead and lay in our rocker
box. Then go ahead and get all of our rocker box
bolts in there hand tight and of course there's a sequence. the sequence is basically they
start from the inner and work their way out so that would be one, two, three, four, five,
six, seven, eight and then these outer ones nine and ten get done last.
Alright guys, we've got the rocker box torqued back down and the next thing we need to do
is go through and go ahead and loosen up all of the adjusters. I know we didn't replace
the valves or anything like that but what's going to happen is when you bring that pin
up to the 12 o'clock it's going to try to rock one way or another by virtue of the lobes
and that would make it very difficult to get the cam gear up there correctly. Because once
we get those loosened up, then we bring our cam straight up to where that pin is straight
up, this is going to go in there and be in that position. Now if it's off one tooth or
another, we just need to pull it back off the cam and readjust the chain on the cam
sprocket itself. Alright guys, we've got our valve lash set
to zero, so you just want to make sure that each one of those just barely turns with your
finger down and the bottom of the cup when it's in the relaxed position just where it's
making contact. And just one more time verified that we are at top dead center on the crankshaft
as well as up on the cam shaft. From here, what we need to do is just go ahead
and put on our cam cover and then our thermostat over here and then on the end we've got that
big stater cover. Kind of heavy. You want to make sure that you don't forget
this little rubber drive gear that goes right there when you're putting on that outer cover.
Other than that, that'll pretty much complete it.
Alright guys, that's pretty much it. Went ahead and got the stater cover back on, when
ahead and got the starter and remounted it so I didn't have to do it while it was in
the frame. The valve cover's on, everything's tightened up, we're sure about the timing,
we've got our new pistons and rings in there, the valves look good, and this pretty much
completes the reassembly of the engine. So what's left now? Well, we've got to get
this back in there. So that will be our last video installment
for this project. Listen, if there's something that I did that
you couldn't see or if you have a question about something that I did, just leave it
in the comments section below and I'll do my best to answer it. If you need any of the
parts or the gaskets or whatnot that we used to put this engine back together again come
see us at partzilla.com. And until the next episode we just want to
say thanks for watching.