How do i change a cam cover gasket on a 1999 harley davidson fat boy
Replacing the gasket on the cam cover of your Fat Boy is not a job for the faint hearted. It''s quite complicated because of the fact that you must get the pressure off the cam to get the cam cover back on once you get it off. You must also be very careful as to not change the camshaft timing with either the pinion gear or the breather gear.
If your Fat Boy has stock pushrods in it, you'll have to take the fuel tanks off, the air filter, and then take the rocker box covers off. Rotate the engine until you get one cylinder to top dead center on the compression stroke with both valves closed. Pull the push rod tube expanders out collapsing the pushrod tube and take the 5/16" bolt at the right end of the rocker arm shaft out. Slide the rocker arm shaft out and remove the rocker arm and the pushrod. Do this on boht the intake and exhaust pushrods. Notice that the pushrods are color coded meaning that they go in a particular location. Do not get them mixed up. Do the same thing to the other cylinder. The purple colored pushrod goes to the rear exhaust, the blue coded pushrod goes to the rear intake, the yellow coded pushrod goes to the front intake, and the green coded pushrod goes to front exhaust.
Now, that you have all the pushrods out of the engine, take the bolts out of the tappet guides and remove them. Keep the tappets in their original bores, do not mix them up. Check the roller bearings on end of the tappets for any up and down play. If you find a worn tappet, it should be replaced. You can replace the gasket on the cam cover without removing the tappet guides but you must remove the pushrods to get the pressure off the cam. If you remove the tappet guides, you will need a pair of "alignment pins" to align the tappet guides with the camshaft upon reinstalling them. Torque the bolts to 100 inch pounds.
Now, remove the cover that covers the ignition timing unit in the nosecone. Mark the timing plate inside the cavity so that you can reposition it in exactly the same place when you go to put it all back together. Remove the timing plate and the timing "cup" behind it. Take all the bolts out of the timing cover. The cover is mounted on two large dowel pins. You can pry the oil pump side of the cam cover off just a bit with a large screwdriver. Then, use a thin putty knife to work the other side loose. YOU MUST HOLD THE CAM IN POSITION BY PUSHING INWARD ON IT AS YOU REMOVE THE CAM COVER. DO NOT ALLOW THE CAM TO COME FAR ENOUGH TO LET IT GET OUT OF TIMING WITH EITHER THE PINION GEAR OR THE BREATHER GEAR. IT MUST BE TIMED CORRECTLY. The bolts that hold the cam cover on are different lengths, remember where they go.
When you go to reinstall the cam cover, make sure you get all the bolts in the correct holes. Reinstall the tappet blocks if you took them out. Reinstall the pushrods, pushrod tubes, and rocker arms in the last cylinder that you removed them from. Torque the 5/16" bolt to 13-15 foot pounds. Wait for the tappets to bleed down and you can turn them with your fingers. Turn the engine until the other cylinder is at top dead center on the compression stroke. Reinstall the pushrods, pushrod tubes, and rocker arms on that cylinder. Again wait until the pushrods will spin with your fingers before rotating the engine.
Reinstall the timing cup and the timing plate in the timer cavity in the cam cover. Make sure you get the marks you put on the plate and the cover aligned precisely. Reinstall the rocker boxes with new gaskets. Torque the bolts to 80-100 inch pounds. Reinstall the fuel tanks.
Mar 25, 2011 |
Harley Davidson FLSTF Fat boy Motorcycles