Will be updated periodically. If there are any pictures or procedures you would like a better understanding on, contact me and I will see if I can post something.

The beginning of project "nightmare". When you remove the engine make sure you have a floor jack with a piece of wood under the oil pan. Regardless, this thing is heavy and ackward to maneuver on your own so have at least one other person around. I removed the engine as a complete assembly, but you may find it easier to take the head and cylinder off first.

Whoa. That can't be good. Aside from the chunks of carbon and grime piled over the dome, you can see the top ridge (especially the right piston) has went all to hell. The bike had overheated three times, and once was pretty bad. It was a slow moving traffic jam, up hill, and blocked into the left lane. Good times.

Here is the top of the combustion chamber, left side with valves removed. Not horrible, valve seats are in spec. Look how dirty the intake runner is. As far as the idea of oversize valves you can probably forget it. May not be too clear in the picture but there is very little valve to valve clearance as it is.

Starting to look a lot better here. I tell ya, I started cleaning the chambers by hand, and I will never forgive myself for that. Dremel makes two very nice wire wheel attachments that are about $1.50 each. I hung the dremel from my ceiling and used the flexicord attachment while sitting at my workbench. 30,000 rpm later the ports and chambers are looking like new.

Alright, scratch the above plan. I found a NOS cylinder head on Ebay for $25. In original packaging and everything! New valve guides/o-rings and exhaust studs already installed! Don't have to sandblast it or repaint it! Score! Now I can use my original as a spare (yeah, like I'm ever doing this again).

Here is the original intake(left) and exhaust(right) valve from the #1 side. Intake was pretty gummed up. When I bought the bike I was going to check the air filter to see how it was. Unfortunately, it turned out he was running no air filter, and who knows how long.

And here is the new head, with new valves, springs, cotters, guides and seals installed. The valve seats recieved a light lapping to ensure an airtight seal, and we're ready to roll.

This is my support fixture (blocks of wood) that I mentioned in the first section of the project page. Just want to keep the rods in the air until you remove them, and keep everything nice and semi level.

The mighty 650 crankshaft. Discontinued by Honda, but like anybody was going to pay $700 for it anyways.

Connecting rod up close. Make sure you keep everything in the order you took it apart, or you're going to face some major problems later on - like the engine not working at all. You can't see it, but the bearing shells have a dab of paint on the sides for identification.

Main shaft and lay shaft. I wouldn't recommend taking these apart unless absolutely necessary (broken gears or worn dogs) If you do keep everything in order! Take notes, and make sure you only try to do one thing at a time. So many people take things like these apart completely, and get sidetracked on something else. Don't rely on Mr. Clymer to remember how everything goes back together.

After you remove the main and lay shaft, you can see the three shift forks, and the shift drum. Check these for wear, and grab some from a salvage yard or parts motor if they are too worn. (Also discontinued by Honda)

Now would be a great time to replace the main bearings. Even if they're still decent, just replace the damn things. The manuals always tell you how to check bearings and measure the wear on piston rings, etc, but it really doesn't make sense to me. Of course, Hondas prices are now rather ridiculous, but if you go this far into a project you might as well do it right the first time and spend the extra cash.

Here the block is after getting back from the machine shop. It was bored .25 milimeters over, and you can kind of see the roughness of the cross-hatching from the hone. Also, the mating surface was very lightly resurfaced to clean everything up.

Rockers. And other stuff. Only reason I took it apart is because I have a cat, and no matter what you do cat hair ends up on everything. And since I'm polishing it, it's a hell of a lot easier to handle and I have a lesser chance of breaking stuff.

I discovered the best way to make sure the carbs are clean is to fully disasemble them. I had previously cleaned the bowls and slides and blasted the jets with carb cleaner, but found that one season of riding clogged everything up again.