It s a good idea to identify the Front and Rear cylinder heads using a paint pen before starting the teardown process.
Use a 17/64 drill bit (or 6mm if you have metric drills or round stock) to lock the camshaft from turning while loosening the cam sprockets.
Remove both cam sprockets using a puller. (they are tapered fit) Note that the FRONT camshaft bolt is LH thread (reverse).
To remove the heads (and reinstall) you ll need a 14mm swivel socket (short 6 point, with built in universal joint) to access the bolt hidden under the camshaft. No need to remove cams. Torqueing that bolt is tricky, as well as the other external bolt that s blocked by the camshaft. Ifyou trustyour pull you can use a box end combination wrench.
Unscrew the water pump impeller by carefully tapping the impeller wheel in a counterclockwise direction (RH thread) with a hammer and aluminum drift. A little heat can help to loosen the Loctite.
The large gear is what Aprilia calls a transmission shaft and serves as a jackshaft khf between the crank and camshafts. A little heat here can be helpful to loosen the Loctite on the nut. Removal of the gear can be difficult too if Loctite has gotten between the gear and shaft, so some careful heat application may be required to liberate the gear.
This is as far as the RH side of the motor needs to be broken down.
A must have is an Aprilia flywheel puller. The M16x2 draw bolt does NOT come with it. If a flywheel locking tool is not available, a thin piece of aluminum wedged between the crankshaft and clutch gears works just fine to lock the crank.
Don t forget to remove this bolt from the RH side. It s the only one from RH side that holds the case halves together.
Extend the sleeves out the case about an inch. No fancy tool needed just turn the crankshaft slowly using the flywheel and the friction from ring tension should push them outward. Keep the pistons near TDC so the rings don t pop out the bottom the sleeves. If the sleeves aren t extended sufficiently, you ll notice them stuck (not loose) while attempting to separate the cases.
7mm bolt that s captured by the clutch release lever. Unscrew but leave in place. Tip: use a paint pen to identify each 7mm bolt head. Makes it easier to identify these larger size bolts when torqueing them later. One 7mm from the RH side Five 7mm from the LH side (plus one above) Eight 6mmfromthe LH side Large aluminum bolt from underneath the neutral switch.
Don t forget to install Don t forget to install the dowel and O ring before refitting the cases. (near the starter)
Make sure the neutral switch detent pin is still installed before refitting the cases.
Don t forget the washer on the LH side of the mainshaft. It can get stuck to the LH case when pulling the cases apart.
The Threebond 1207B black sealant is readily available through most marine engine shops for about $30 US.
A little dab on sealant at the bottom of the sleeve counter bores can t hurt.
A little smear of sealant at the sleeve/case interface is probably a good idea too.
Modify a spare bolt with a 5/32 (or 4mm) hole drilled through the center of it (use a lathe). Lock the crankshaftposition by slipping the drill through the bolt and into a alignment hole in the crankshaft. This should ONLY be used for timing the camshaft sprockets and NOT for torqueing.
To set the cam timing use a 15/64 (or 6mm) drill to lock the cam in position, and while the crankshaft is locked in position, snug up the cam bolt. Se
Before reinstalling the water pump impeller wheel, make sure the washer is installed underneath. Use some red Loctite on the impeller wheel and tighten it with either a strap wrench or a hammer and aluminum drift. Excessive torque not required since the water pump load on the wheel is always tightening it.
Install a couple long screws with the heads sawed off to guide the stator cover onto LH side. The magnet is very strong, and without the dowels damage to the seal in the stator cover could result. Remove, clean, and red Loctite these six screws unless already done. They have a tendency to back out.
u Make sure the little collar between the shift lever and shifting drum doesn t fall out (underneath the clutch basket).
Special tools and materials needed General notes Aprilia flywheel puller 9100839, and M16x2.0 bolt Red Loctite Threebond sealer 1207B (Google 0351053 for Suzuki sealer) 14mm 6 point swivel socket for head bolts 5/32 drill for crankshaft timing alignment 15/64 drill for camshaft timing alignment M8 bolt with 5/32 hole drilled through the center 2 jaw gear puller Good torque wrenches for 10 Nm 110 Nm range Additional recommended procedures Good practice to completely disassemble engine Measure cylinder sleeve protrusion, 0.000 0.004 Lap case halves with some 500 grit sandpaper on a surface plate to insure flatness Thoroughly clean case sealing surfaces with contact cleaner or alcohol and coat entire RH case mating surface with Threebond using small brush. Replace rod or main bearings if there s any sign of distress or corrosion Check seal orientation in the stator cover (lip should be on inside of cover) Contact i Zapp at ApriliaForum.com for corrections / changes