A while back, I picked up a CB750F (aka Super Sport) for my cousin-in-law to go along with a learning bike on a trailer-ride to Brooklyn. At any rate, I got the thing fairly cheap, knowing that the engine was seized. I took a risk on the guy’s word that “It was running last year, but I left it out over the winter and it probably got moisture in the cylinders.”
So, I did what I always do and dumped some Marvel Mystery Oil down all four cylinders and let it set for a week. I tried the kickstarter and it was stuck. I tapped the electric start and it was stuck. I tried the bolt on the rotor and it was stuck. So I let it sit for two weeks. Three weeks. Two months. Still stuck. I decided a couple days ago it was time for more drastic measures. I mixed up a batch of “special mixture”, basically ATF & acetone and prepared to dump it down the cylinders. Prior to that, I wanted to syphon out the MMM so as not to dillute my new concoction. Well, #2, 3, and 4 were all empty. We have a winner. 99% chance that #1 is the piston that’s stuck. I put a little special mix down #2, 3, and 4 just for good measure and filled #1 to the brim. I let it sit two days and still no dice. Finally, I dug out my handy propane torch and went to town on the cylinder block hoping to expand my way to freedom.
Nothing. Fine. The engine is coming out.
First thing to come off was the exhaust. This is surprisingly easy on the Super Sport as compared to the K model.
Just for jollies, I decided to check out the points. Yes, that’s a nut drilled out and filled in with a smaller nut. I’ll have to replace that once I get this thing running again.
Next to come off was the oil filter. Not a lot to this, just a matter of using the proper socket on the bolt. You could tell some previous owner hadn’t done so and I’ll probably wind up replacing this bolt as well.
Next was the electrical connection to the points. Mostly, I took this picture so I could see which bullet goes into which receiver..given that both receivers are white.
Next, the electrical connection on the other side of the bikes:
Followed by the connection to the top of the solenoid:
Finally, the ground strap back on the right side:
Getting to this one of course requires pulling the top long engine mounting bolt. Continuing on to things I didn’t take pictures of, I pulled the long bolt out of the front of the engine along with the couple of short bolts holding onto the front of the frame. It feels like there’s still one more bolt holding the engine in in back, but I’ll figure that out tomorrow.
Another process I didn’t show was taking care of the chain. I didn’t want to cut the chain, nor could I get the engine out with the chain looped around the spreckets. I loostened the tensioners and pulled the rear axle. This gave me enough slack that I could get the chain around the rear sprocket and now it’s sitting slack on the ground. This still isn’t going to work, however, as it loops around part of the swingarm and won’t let me pull the engine out in the long run. Tomorrow, I’ll pull the master sprocket cover and hopefully find a way to loop the chain over the master drive sprocket. If not, I’ll just cut it and throw a new one on. Couldn’t hurt, anyway.
That’s where she’s at right now. The engine is basically disconnected from everything and tomorrow night I’ll lift her out of the frame, pull the head, and see what’s actually going on in there. Depending on how I’m feeling, I may get it running on the bench. I’ve never actually gotten an engine running on the bench before, so it could be fun.
That’s it for tonight. Ride safe.
Update 2009-10-21:
Unfortunately, there’s isn’t going to be a “Day 2″ or anything else. I wound up pulling the engine using a sling made of cotton cord and a three foot bar. It was a frustrating and irritating process, but I did manage it on my own. Didn’t take the time to do pictures because I was too busy straining my back and cursing at the bike. After all that work, it turned out that the engine was solid rust anyway. “Ran last year” my ass. In a bout of frustration and desire to have my workspace back, I sold the bike and the engine / block-of-rust to my buddy Tom for $100.