Evolution Motor Disassembly

[ScreaminEagle]

I'm tearing my bike apart and thought I would post a step by step teardown with pics. Assuming your EVO motor is out of the frame the carb and breather should still be attached. Remove the carb's bolts with a 1/4 inch allen head. Only two need to be completely removed because the other holes are slotted. The 2 breather bolts are removed with a 3/4 socket


Note: I am not a perfeshunel, but I did stay in a Holiday Inn Express one time

[ScreaminEagle]

Step 2 Rockerboxes

The top four bolts of the rocker cover are removed with a 3/16 allen head. Remove these bolts in 1/4 turn increments until all the pressure is gone as not to warp the cover. These bolts will have a metal washer and a fiber washer. There are three pieces to the rockerbox, the first two will come of now.

[ScreaminEagle]

Rockers cont.

Ok before you remove the rockers and bottom rocket box, the cyl need to be at top dead center. First you should remove the rotor, flip it over and insert back on the drive shaft. This give you a better grip for turning over the motor. Next remove the bolt above it so you can see the timing marks. I'm doing the rear cyl first so I'm looking for a small dot as shown.

[ScreaminEagle]

Rockers cont.

Now that the cyl is top dead center you can remove the 2 3/16 allen heads, 3 7/16 bolts. These are removed in 1/4 turns as well. Next are the four 1/2 inch bolts, also removed in 1/4 turns. Next remove the pins holding the rockers in place with a soft punch. DO NOT HAMMER OUT!
Make sure you label thes so they can go back in the right spot. Now you can remove the pushrods. These are color coded. Started from the rear they go purple, blue, yellow, green. I was always taught to remember "pussy brings years of grief" to remember their order. The lower rocker cover is then popped off.

[ScreaminEagle]

Heads

Remove the pushrod cover by removeing the clip with a screwdriver then popping them out of the tappet block. Now it's time to remove the head. This is down with a 1/2 12 point socket in 1/8 turns. Go slow as not to warp the head. Do this in a crisscross pattern as shown on the paper. After all the pressure is relieved slap the bottom of the head to break the seal and remove. You will notice that two of the bolts are longer they go on the cone side.

[ScreaminEagle]

Cylinders

Next you can pop of the cylinder. Be sure to raise it up just enough then cover the hole with a rag so you don't get carbon or broken rings down in the case. Also support the piston with your hand so it doesn't hit the studs. The front end is stripped in the same way. When setting to TDC look for the slot in the window as shown. Make sure you mark the cylinders as they are identical and need to go back in the same place

[ScreaminEagle]

Tappet blocks

Now it's time to remove the tappet block and lifters. This is done by first removing the four bolts with a 1/4 12 point socket. Next get yourself a paper clip bend it and insert into the oil holes in the lifters. By pressing back on your special tool you can lift out the tappet block and lifters. Repeat these steps for the other one. Make sure to mark them so they go back in their original place.

[ScreaminEagle]

Nose cone cover

It's time to remove the nose cone. You must first drill out the rivets on the timing cover and remove. Inside is another cover removed with a phillips head. Inside that is a gasket and then the sensor plate. Make a mark on the plate so you can put it in the exact place it came from then remove with a flathead screwdriver. It's attached to a wire so tilt it out of the way and remove the rotor with a 5/16 socket. Now remove the cover with your 3/16 allen wrench make sure to arrange them somehow so they go in their original holes. I draw a pic on some carboard and poke them through. They cover will pop off by pressing from in side the tappet block holes. Be sure to hold the cam cause it will want to come out too.

[ScreaminEagle]

Inside Nose Cone

You will see the big gear which is the cam to the left is the nylon breather gear and underneath is the pinion gear. There is a spacer on the breather gear which is usually stuck to your cover from oil. This gear pulls out as does the cam with it's thrust washer and any shims. Your motor should look like mine now. You can remove the cam seal from the cover and the cam bearing I'll be doing later,

And that's it. You could split the cases but I'm not going to. Also the pistons can be removed for cleaningand new rings, but I'm not doing that yet. Damm I'm ready for a beer now!!!:chugger:chugger

[yochanon]

Nice write-up and great pics too! Right on man!

[ScreaminEagle]

Nice write-up and great pics too! Right on man!

Thanks I hope this can help someone down the road.

[o8h0g]

Don't forget that the pushrods for intake and exhaust are 2 different lengths, they have color codes on them, putting them in backwards would not be good.

[ScreaminEagle]

Don't forget that the pushrods for intake and exhaust are 2 different lengths, they have color codes on them, putting them in backwards would not be good.

Very true I have have posted the order they go from rear to front of engine purple, blue, yellow, green.

[o8h0g]

I must have missed that.

[ScreaminEagle]

Hopefully I'll be getting my heads and cylinders back soon. After I paint them I'll start a thread on the assembly