Removing Harley Evo Heads

Mike has the rocker box assemblies removed from our 1988 Heritage Softail and is now prepared to remove the front and rear Harley Evo heads and cylinders.

There is a de-torquing sequence for loosening & removing the head bolts.There are 4 head bolts for each Harley Evo head. Two long and two short. The short head bolts belong on the left side, near the spark plugs. Mike begins by cracking each bolt loose approximately 1/8 of a turn. Then he starts over again and loosens each bolt approximately 1/4 turn more.

The de-torquing sequence is important because the cylinder studs are under a lot of stress. If not careful, a stud can pull up; ripping the aluminum case threads along with it. As Mike removes the Harley Evo head bolts, a couple of bolts are removed with the cylinder studs attached. This is not because threads were pulled from the crankcase. The studs simply unthreaded from the case. This scenario is not uncommon.

If a cylinder stud was to pull from the crankcase, it would need to be repaired by having a Time-sert installed into the crankcase. It is vital for this repair to be completed with precision. If the Time-sert is not installed into the case correctly, the cylinder stud will not stand straight or in line with the other studs. The cylinder will not be able to be installed correctly if this is the case.

Next, Mike removes the Harley Evo heads and demonstrates the procedure for valve disassembly / removal. The factory service manual gives us a laundry list of things to inspect in this area. Before removing the cylinders, it is important to blow off any loose debris that might be near the cylinder bases. Every precaution must be taken in order to avoid debris from falling into the crankcase. Once cylinders are lifted from the studs, it is important to protect the pistons & rings if they are to be reused. Do this by sliding a rubber hose over the cylinder studs.

Mike removes the wrist pin clips and wrist pins which releases the pistons from the connecting rods. It is important to label the pistons for front & rear and for direction. Even if the pistons are not going to be reused. This information may be important for reference as you move forward. Mike comments on the importance of wrist pin bushing condition and wrist pin fitment. He also discusses the inspection of connecting rod run out, side play, and checking for possible binding.