Repair 7

An engines head gasket separates the engine block and the cylinder head. It seals the cylinders and protects against coolant and oil leakage. If a gasket breaks and fluids are allowed to escape, the engine will eventually overheat and can cause damage that can result in the need for repair or replacement. If a gasket breaks and leaks compression, your power and fuel economy will suffer.

Overheating

When an engine overheats, the head gasket materials expand and sometimes crack. Once compromised, the gasket will leak coolant or compression and eventually the engine can stop working completely. Common causes of overheating include loss of coolant due to leaky hoses or a clogged filter or radiator.

Excessive Mileage and Wear

Cars are not made to run forever, and eventually the head gasket will wear and can crack. Taking good care of your vehicle and maintaining fluid levels can increase the life of your head gasket and engine.

Human Error

A number of installation issues can cause a head gasket to be improperly sealed. If your engine was worked on recently and you experience a head gasket failure, its possible that something was done incorrectly during the repairs. Head gaskets need to be installed in a particular sequence using the proper tools and to the correct calibration or they can leak and crack.

Poor Design

Occasionally, a manufacturer oversight will cause a gasket to be approved even though it is substandard. The materials can wear over time or suddenly crack. Check with the dealer or search for known issues for your vehicle. Dont miss regularly scheduled maintenance and check fluid levels often so that if a problem develops it can be addressed before the entire engine is lost.

Valve covers cover the connection between the push rod ends and the rockers of your engine. Valve cover gaskets ensure that the oil coming to the top of the engine to lubricate the rocker arms does not leak from the valve covers. As you use your vehicle, the valve cover gaskets begin to wear. Wearing begins to break down the gasket, allowing oil to leak out of the engine. Fixing leaking valve cover gaskets keeps your engine from seizing from lack of oil.

Instructions

1

Scrape the old valve cover gasket from the gasket flange with a metal putty knife.

2

Apply gasket remover to the remaining gasket material with a small paint brush. Allow the gasket remover to sit on the material for 25 to 45 minutes.

3

Wipe the gasket loosened with the gasket remover from the valve cover flange with a rag. Apply a second coat of gasket remover to the flange to remove any remaining gasket material. Wipe the flange dry with a clean rag.

4

Apply a 1/8- to 3/16-inch thick bead of RTV sealant to the cleaned flange.

5

Press a replacement valve cover gasket into the wet sealant. Allow the sealant to cure for 15 to 20 minutes.

6

Set the valve cover over the engine head to cover the rocker arms. Hand-thread the fasteners over the flange to hold the valve cover in place.

7

Tighten each screw with a matching socket attached to a ratchet handle.

8

Repeat the process on the other side of the engine if it contains a second valve cover.

The Evolution engine was a significant upgrade over the preceding Shovelhead power plants. Part of the redesign was the replacement of the spade-shaped Shovelhead rocker covers with rocker covers that looked like a stack of blocks. Harley cheerfully nicknamed its new engine the Blockhead. Unfortunately, the Blockheads rocker covers leaked. The covers were redesigned four times. The earliest rocker box gaskets, and the worst, were made of cork -- they were nicknamed "glue and screws." Later generations of these gaskets were made of rubber. Although you can replace these gaskets without pulling off the gas tank, experienced mechanics usually do so.

Instructions

1

Park your Harley in a well-ventilated area. Turn the petcock to off. Allow the engine to cool down completely.

2

Loosen the fender tab bolt on the back of the seat with an Allen wrench. Remove the bolt and washer. Pull the back of the seat up and back to remove it.

3

Disconnect the negative battery cable from its terminal with a box wrench.

4

Remove the console bracket bolt or bolts. Use a box wrench on consoles attached to the bracket with a single acorn bolt. Use an Allen wrench on consoles attached to the bracket with two or three Allen bolts.

5

Loosen the worm clamp that connects the fuel line to the petcock with a flat-head screwdriver. Remove the fuel line from the petcock.

6

Drain your fuel tank through your petcock into a large gasoline storage can. If you have a split gas tank, you must also disconnect the crossover hose and the fuel venting hoses on the bottom of the tanks.

7

Remove the front and rear mounting bolts, washers and nuts, using a box wrench on the nuts and a socket wrench on the bolt heads.

8

Unplug the fuel gauge connector under the gas tank on later Evolution models.

9

Lift the tank straight up and off the motorcycle and set it aside.

10

Remove the Allen bolts that fasten the rocker cover to the engine. Remove the cover. Work on one rocker cover at a time, beginning with the front cover.

11

Remove the metal gasket, which is called an inner rocker cover or a D-ring. Remove the old gasket. Some gaskets will need to be scraped off.

12

Examine the used gasket and rocker housing. Gaskets for housings with only a partial shelf gasket use adhesive. Housings with a shelf to fully support the gasket do not need adhesive.

13

Position the gasket on the rocker arm assembly using adhesive if needed. Replace the thin metal inner rocker cover and the rocker cover.

14

Replace and tighten the rocker cover bolts according to the specifications in the shop manual for your Evolution. Generally, these bolts are tightened to about 10 foot-pounds of torque.

15

Replace the gas tank and reattach the pigtail connection for the fuel gauge. Reconnect the fuel line to the petcock using a worm clamp and flat-head screwdriver.

16

Reattach the console to the console bracket. Refill the gas tank. Reconnect the battery cable and replace the seat.