By Petemoss, AF1 Forum
Tools needed: 4mm allen wrench to remove all the fairing pieces 2.5mm allen wrench to remove battery holder 5mm allen wrench for valve cover bolts 8mm and 10mm socket wrenches 8mm and 10mm standard wrenches philips screwdriver set of valve clearance measurement shims rubber mallet to loosen valve cover probably something else Iforgot Valve Clearances: My Aprilia Shiver service manual lists the clearance ranges as Intake :: 0.11 - 0.18 mm (0.0043 - 0.0071 in) Exhaust :: 0.16 - 0.23 mm (0.0063 - 0.0091 in) It is essential you do this check on a cold engine. Let the bike sit over night, or about 8 hours, after riding to ensure it is cool enough. Checking the valves is easy, but adjustments require removing parts that couldallow the timing to shift and make the bike to be unrideable. I recommend you consult the Aprilia service manual for more details. Hopefully this guide will make visualizing the task easier.
To get to the valves, you need to remove quite a few parts. Go slow and take it easy, and you will be able to accomplish this in a few hours. Between doing the work, taking pictures, taking breaks, andhelping my wife work on her SV, this whole job took me about 5 hours. My valves turned out to be in spec, so I didnt need to remove the cam shafts or adjust the valve clearances. That would have added more time. First things you gotta remove are the fairing pieces from the fuel tank. There is one piece around the ignition switch, and three pieces on both the left and right side of the tank. Be sure toalso remove the bolts to the left and right of the ignition that hold the front of the tank down (shown with yellow arrows).
Once you have the fairing pieces off and the front of the tank loose, you can pivot the tank up. If you can, remove the braided drain hose from under the left rear part of the tank. I didn’t do that and had some tension pulling the tank up until the hose released. Thenylon braided hose is attached to a tray under the fuel valve that collects drips of fuel and routes it around the hot engine.
This shows the fuel hose disconnected from the red fuel valve. The collection tray is laying below, on the cylinder head cover.
After the hoses have been disconnected, unbolt the tank and remove it. You will then see the top of the rear cylinder head between thebattery and airbox.
Remove the four head cover bolts, and the spark plug boot. Then remove the bracket holding the battery in place and slide the battery up to provide clearance for the head cover to come off. Below is what you will see under the cover.
The valves are covered with a pair of cam shafts, each with a gear attached to one end. The shafts are turned by the action of a third gear thatis powered by the cam chain. The gears and cam chain are visible towards the bottom of the photo above.
At this point, I checked the valves on the rear cylinder. To check the valve clearance, you need to get the cam lobe off of the top of the valve so that it isnt compressed. The easiest way to do this is to shift the bike into 6th gear and rotate the rear wheel while up on a rear stand. Itis even easier to turn the wheel if you remove the spark plugs. I rotated the rear wheel forward, as that is the way the engine turns. A mechanical engineer buddy says it is OK to turn it in reverse too, but I didnt do that. When you turn the wheel it will turn the cams. You want the cams to wind up in the position shown below - note the cam lobe pointed away from the top of the valve (yellowcircle). There is a second cam under the cover that can be checked through the window (yellow arrow).
In case you havent checked valves before, this is the tool you need. It has many shims bound together, each of a different measured thickness. The ranges you will need are listed at the top of this how-to. The measuring procedure is to put a shim between the cam lobe and the top of the valve. The...