Archive for the ‘Maintenance Log’ Category
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.
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.
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.
I don’t have the tools necessary to fully disassemble the heads or to grind valves and seats so I started looking for a local machine shop to get the heads checked out. Turns out that even in this little town of 10,000 there is a local shop named Competative Edge. They are car racers. Build and maintain their own dragsters. Might know a little bit about engines. Off we go.
Two days later I got my heads. Good news. Valves are good. Seats are good. Front head valve guides COULD be replaced if I had a set but are still very usable. A LOT of carbon in the combustion chamber. Enough that there could have been some leakage around the valves while they are seated. Good news is that carbon cleans up pretty easy 🙂
Cylinders appear to be free of taper so I’m going to just break the glaze on them and go back together with the same rings tomorrow afternoon. Hoorah! Back on the road this weekend with all the new stuff I have accumulated over the winter. Ought to be a good summer or riding coming up.
I’ll try to document the assembly process with a lot of pictures.
Ride safe.
Even with the well known quality of the James’ Gasket Company there is a gotcha in using their engine set. The base gaskets do NOT have the necessary holes in them to allow for the free return of top end oil to the crankcase! Want to see a shovel puking smoke? Use their gaskets without cutting the necessary holes!
In all fairness I should mention that when I went to my local Harley shop and asked them for a set of cylinder base gaskets, the ones they provided also did NOT have the required hole for the oil return…. Here is what you must do. Get a plain old paper hole punch just like the ones you used when you were in grade school. This tool will be used to actually cut the hole through the new gasket. In 1982 and 1983 shovelheads, HD implemented an “oil consumption reduction package” in the design of the motor. What this modification amounted to was the blocking of one and the addition of one hole through the cylinder. On the primary side of the motor the original oil return (that would typically feed oil to the oil rings when the piston is down and let it dump to the case sump otherwise) has had a small tube inserted into it and a passage drilled through the base of the cylinder and the mating surface on the case. This hole MUST be cut into new gasket or you will be sorry!
On the opposite side of the motor (cam side) there is originally plumbing installed that connects each cylinder a lifter block providing a third oil return patch (The afore mentioned hole, down through the push-rod tubes, and via this third hole. If the plumbing between the cylinders and lifter blocks has been removed (very likely) then there is no need to be concerned with the cam side “missing hole.” However, if your engine does still have the external plumbing to the lifter blocks you must also cut a hole in the gasket for this path.
This trap is easy to fall into since a cursory glance at the cylinder would lead one to believe that the oil return via the inside of the cylinder is the right path and as such the hole through the cylinder base and case can be blocked by the gasket. Bottom line, the primary side hole can NOT be blocked off. Check your gaskets and make sure you have all the holes you need – or see if you can get a job fogging for mosquitoes – it will really be that bad!