Posts Tagged ‘top end removal’

This post is a continuation of this thread. 

Having removed the heads as described in this post we are ready to inspect the barrels and remove them if necessary.  Here too you can either roll the bike while in gear or use the started to roll the motor over so you can inspect the wall of the cylinders.  In my case I was surprised to find I could still see cross hatching from the honing stones!  Nice.  However, since I haven’t been in to this motor before I wanted to shake the rods and look at the piston skirts and flywheels.  So I decided to remove the cylinders regardless of the condition of the cylinder walls.

The front cylinder is different than the back and cannot be interchanged.  Typically the front jug casting number will be an even number while the rear is an odd number.  In my case these castings are 16568-78 in the front and 16587-78A in the rear.  The numbers not being of the same revision tells me that (at least) the rear cylinder has been blown up and replaced. 

Each cylinder is held in place with 4 base bolts and triangular base washers.  Roll the motor over until the pistons are bottom dead center.  Loosen and remove the nuts from each cylinder.  Carefully free the cylinder from the base.  Be sure that you don’t let the piston fall to the front or rear when it comes free from the cylinder.  I then roll the motor over to the point the piston on the front cylinder is being pulled down into the engine case.  I place a socket extension through the piston wrist pin and then very carefully roll the motor over until the extension is resting on the case’s base gasket surface.  This way when you pull up on the rear cylinder you will not accidentally pull the piston down risking damage to the piston.  Once secured, remove the rear cyclinder in the same manner as the front.

That’s pretty much got us to where it time to see the local machine shop to spec your cylinders and ring end gaps to see if you need to bore and replace pistons or not.  In my case I found what appears to be a brand new piston in the rear and one with only a small amount of carbon on the front.  All of the observations going to support my initial theory about this bike.  The winner blew it up, fixed it and sold it.  Cool so long as there is no hidden damage deeper inside.

With the guts exposed I got the check out the nice set of S&S rods and fly wheels making up the guts of my bike.  Examination of the serial numbers on the flywheels reveals a 4.5 inch stroke (2SL trailing in the serial number) making this baby a 93 incher as I suspected in the beginning.  I don’t have a tool for measuring the bore of the cylinder very accurately but I do see .090 on the rear piston.  .090?  Seems like a LOT over.  Can’t see what the front says due to carbon.  Definitely has to be accurately measured and put in balance it isn’t.

3/3/2010 update:  From what I can find on the net it seems that the pistons are S&S stroker pistons and they seem to be measured against a stock 74 c.i. cylinder.  When using the 74 as the baseline then an 80 c.i. cylinder is  already .060 over (according to S&S’s spec sheets.)  Therefore, my .090 pistons are really .030 over the stock 80 c.i. bore.  I like that a lot better than thinking my cylinders are bored to .090!

Now I know what’s in there and that the rods feel pretty damn good.  Machine shop here we come.

This article is a continuation in series of posts that start here.  The post preceeding this on is here.

Having competed the tasks in the previous posts we’re ready to get the what started all of this.  Removal of the cylinder heads.  Each head is secured by 9/16 bolts, 5 bolts per head, the overhead oil return line on the rear head, and a cross-over line line between the front and rear heads.  Loosen both sides of the cross-over line between the heads. and both ends of the read oil return line. 

It is usually not practical to get the head bolts with a ratchet.  You need a GOOD, TIGHT FITTING box end wrench.  For the rear head you will need either a 9/16 “brake” wrench (shaped like a U) or one bent enough to clear the starter housing area of the primary cover.  This tool is for the back left head bolt on the rear jug.    It’s a bitch both on and off. 

For the other bolts, If you have a six point box end, use it whenever possible.  It can’t hurt to loosen the bolts in a star pattern.  We’ll start on the front head.  Here all five bolts are pretty easy to get to and remove.  Once they are all out you can carefully lift the head from the cylinder and remove it from the bike.  Set the head aside for now.

The right rear head bolt cannot be removed from the cylinder without loosening the cylinder base bolts and lifting the cylinder enough to allow the bolt to drop out.  Remember that when re-assembling!  Take a deep breath and commence to remove the rear head.  In my case this involved a rounded bolt head.  I didn’t know how I was going to get the sucker out but thanks to Craftsman Bolt Extrator in 15mm and a universal joint I managed to twist things just right and got it loose!  These tools are amazing!  Must have.

When I got to the notorious back left head bolt I was pretty surprised to find it quite loose.  It came out pretty easy and revealed that it was likely the cause of the blown gasket.

Having already removed the tank, coil and carburator it is time to remove the pushrods and covers.  Before you start you might take a minute a remove your spark plugs (or one from each head in my case.)  It will make it a lot easier to roll the motor and get the tappets bottomed out.

Using your fingers you should be able to press down slightly on the retaining gusset located near the top of each push rod cover tube.  While slightly compressing the retaining gusset use either a pair of pliers or a regular screw driver to grip the raised nurl on the locking clip (about an inch above the retining gusset) and pull out to free the bottom of the clip.  Repeat this process for each of the four push rod cover tubes.

Lift the bottom of the front exhaust push rod cover tube de-telescoping it to as short as possible.  I then use a piece of coat hanger with a small hook on one end and a hanger on the other to hook the bottom of the push rod cover tube and hang the other end on the top of the rocker cover.  This gets the damned tube out of your way and frees your hands for other uses. 

Once you have the cover tube out of the way either use your starter or put the bike in 2nd gear and roll the motor until you see the push rod bottom-out in the lifter block.  In this position you should be able to see the adjusting, locking and fixed bolt faces.  Using the fixed (bottom) and locking nuts (tightly secured to the fixed piece) and two 7/16 inch wrenches break to locking nut loose and spin it all the way up the adjusting screw.  Once topped out, thread the adjusting screw into the fixed nut until loose enough to pull the push rod from its tappet seat.  I keep each push rod with the same cover tube and mark them so I can put each back where it came from.  Maybe overkill bit can’t hurt.  Notice that the front intake push rod is longer than the others?  Do and remember it.

Repeat this process for each of the remaining push rods.

Sorry to say that about this time my hands were getting greasy enough that momma took the camera away.  Damn woman!  So, anyway, no pics from here.

Removal of the carburator and intake manifold is straight forward and pretty easy.  Remove or free the fuel line so it doesn’t interfere with removal of the carburator from the engine.  Remove the two bolts that attach the carburator to the manifold.  This is done from the left side of the bike.  I fabricated a T-handle allen wrench many years ago that makes reaching the two allen bolts a breeze to remove.    Once removed there is a fiber block located between the carbuartor body and the intake.  Don’t lose it.  On my bike the breather backing plate is attached to the front head for stilibility with a custom bracket.  I have also used a piece of aluminum that bolts from the intake to the top engine case bolt.  Whatever method yours is attached with – disconnect it so that carburator is now free from the engine.  Remove the small screw that brackets the throttle cables to the carburator body.  This frees the cables so they can be easily rotated and removed from the carburator.  Set the assembly aside in a safe place oriented as if it were still mounted to the bike.  This will keep the float from being bounced around and perhaps damaged.

Once the carburator is removed the intake manifold is pretty easy as well.  The stock clamps use a phillips screw to tighten and loosen the clamp.  Loosen both to the point the you can easily  pull the mainfold free from the heads.

This is a continuation of  this post relating to removal of the gas tank.

Next in my progression is to loosen the coil from its mount in preparation for removal of the top motor mount (both shown in images 1  and 2 below.)  My bike uses dual coils and plugs.  I am not going to completely remove them so I can not worry about getting them wired back together right.  Keeping track of which plug wire connects to which coil port will be enough for me.  I documented its loosening and wire orientation in images 3, 4, 5, 6 and 7 below.  Finally I cut the tie wrap holding the coil pack taught and in the way.

Now remove the top motor stabelizer bolt as seen top center in image 1.  Once it is loose, remove the 5/8 nuts securing the mount to each head.  Note the placement of washers, one on the bottom and one on the  top of the mount on each head.  The mount is now loose and can be removed and set aside.

Over the winter and during my my house remodelling project I managed to pick up a few pieces and parts for the old girl.  I acquired a 60602-79C inner primary new in the box (hope it interchanges as it should), a stock muffler bracket, a new set of CycleTech 37 inch slash cut drag pipes, and a HD Race Brace for the 91 circa softtail.  It doesn’t fit but I figure that I’m better off starting with something that has the basic geometry from which I can alter the fit to suit the need.  I also have ordered but have not yet received the stock rubber frame mount for said stock muffler bracket.  All good stuff that comes with high hopes of reducing/eliminating the mystery vibration and the torquing of the inner primary and the continuous loose pipes.  Could I be asking for too much?

As I noted in my last post, I noticed evidence of a blown head gasket on the rear cylinder (in the form of a hole burned through my jeans while sitting at a drive through window and touching my leg to the rear pipe – a little on the HOT side in my humble opinion.)   Yesterday the temperature got up to 62 degrees here.    I decided it was time to drag her out of the garage and tear off the top end.  This would give me the change to replace the blown head gasket and to see what shape my cylinder walls are in.  I might even pull the jugs just to shake the rods and to see if they are stock or stroked.  So, I spread out a tarp and commenced.

For those who have never done this I will document the steps that I took.  I like to document things as they were when I started so I take a lot of pictures during the tear down process.  I have a hard time remembering where I put the wrench I was using 5 mnutes ago let alone which plug wire went where (I have dual coil, single fire, dual plug ignition.)  If you undertake such a project I would recommend that you do the same.  Hell, you might even jot down some notes….

First thing is to remove that precious gas tank so that it doesn’t get dinged during the top end removal process.  You might not need to remove the center console to get the tank off.  If you choose to attempt such removal then be sure to trace your hot and ground wires to their termination point and remove them before attemptinig to remove the tank from the frame.  Since my guage isn’t working and I wanted to see what was under it, I decided to remove mine seperately from the tank. 

Simple removal of the three allen head screws and the gas cap (shown in images 2 and 3 below) is all that is required to get the console loose from the tank.  The fuel guage is wired to the tank sensor, a hot source and grounded to the frame via the front tank bolt so when you pull the console loose be careful not to pull against these wires. 

Carefully remove the console from the tank.  The rubber pads may come with or stay on the tank.  Be aware of their existence and gather them up in a safe place.  Free the sensor wire connected to the tank (image 4) first.  Then the ground  from the frame (image 5, sorry for the quality) and finally the hot wire.  I removed the hot feed from the guage itself Oimage 6 below) so I didn’t have to cut any wires or into any wire harness components.  The console is now free to be placed in a safe place.

I then removed the 2 bolts hidden under the seat that secure the tank to the frame (image 7.)  Then the crossover line seen in image 8.) and finally remove the long through-frame bolt holding the tank in place.  Now you can carefully rock the tank from front to back easing it from its perch atop the frame backbone.

Don’t forget to throw some wax under the tank before remounting it.  Alot easier now than later.  Now we go on to removing the coil from its mount in order to remove the top motor mount.

This thread is continued here.

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