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Thread: DIY: Shiver Valve Check, Illustrated

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    apriliaforum newb petemoss's Avatar
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    Jun 2009

    DIY: Shiver Valve Check, Illustrated

    I bought my shiver 2 weeks ago and already have over 1500 miles on it. I hadnt yet checked the valves, and given that I wanted to learn more about the engine, i decided to dive in. I havent seen a close up description posted anywhere, and the pictures in the service manual are small, so I thought I would take photos to share what I find.

    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 I forgot

    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 could allow 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, and helping 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 to also 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 didnt do that and had some tension pulling the tank up until the hose released. The nylon 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 the battery 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 that is 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. It is 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 (yellow circle). 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 shim that fits with ust a slight drag is the correct measurement. If a shim doesnt fit or fits very tightly, then it is too big, so dont try to force them into the gap. If it gives no resistance, then it is too loose, and the next largest size shim should be tested.

    While doing this work, be sure to do the other inspections. My coolant level was too low, so I topped it off with a 50/50 mix of anti-freeze and distilled water. Dont trust the people who set up your bike - verify levels yourself!

    To access the front cylinder, you will need to get the radiator out of the way. Remove the two bolts holding it on to the frame and horn bracket. Also remove the bolt holding the reservoir to the frame, and slide the radiator off the peg on the right side of the bike. You will then have slack for it to dangle down out of the way of the head cover.

    Left side view. You can see where I have removed the evap canister and bracket. Good riddance!

    View of right side. the dangling reservoir kinda blocks the view, but provides the necessary clearance.

    After removing the 4 head cover bolts and the spark plug boot, you can remove the head cover. If it is stuck on (likely), you can tap it with a rubber mallet to loosen it. NEVER use a metal hammer to loosen it, as you would likely crack or damage the head cover or cylinder body.

    Again, with the bike in 6th gear and up on a rear stand, rotate the rear wheel forward and get the cams rotated off of the valves. Then you can test with the clearance measurement tool like shown below.

    All of my valves were within spec, so I didnt go any further. The only way to adjust the valves is to remove the cam shaft covering the errant valve and replace the shim under the bucket. To remove the cam shafts, you will need to remove the housing covering the shafts, with the opposite shaft pinned in place with a 6mm pin through the gear. Since I did not perform any adjustment, I will leave it to someone else to show the procedure to safely remove the cam shafts. I dont plan to open the heads up again until the 12k mile check. Sorry I couldnt go any further, but if it aint broke, dont fix it!

    While I had everything apart, I added a longer vent hose to the tank to make up for the one i removed while removing the evap canister. To do that, I needed to separate the painted plastic cover from the black plastic tank. Below are pics of the two pieces, for the curious.

    Last edited by petemoss; 06-28-2009 at 11:08 AM. Reason: clarifying wheel rotation language
    01 Bandit 1200
    08 Shiver 750

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