So I've been lusting after cafe-style bikes for a while now, and I got the opportunity about a month ago to pick up a nice 1975 CB750F. I must say that this forum had alot to do with my choice - I lurked around here quite a bit to see what people were doing, and what bikes were best. Style, power, and part availability made my choice easy. I picked this bike up looking pretty good, but not running. Owner said it ran when he parked it (stop me if you've heard that before). Since it didn't fire, I talked him down $300. I loaded the bike up, and trucked her home. A couple of things had been done - drag bars, headlight, and a fiberglass rear body that the owner had created himself. To finish it off, a crazy/cool Evel Knevel paint scheme. Here's a couple of pics the way I bought it - pretty decent start, I must say.
The plan is simple - not looking to go full restoration or all-out custom. A budget build, just updating some choice parts to make it cool, reliable, and fun, with some cafe-inspired styling. I've done customizing before, but not a full rebuild, and never on anything older than 1995. Should be fun!
First task is to get it running. Off come the carbs, and here is what I find:
Gnarly. So I spend a weekend cleaning them out, soaking them, etc. (My first time doing this). Drained the old gas, cleaned the petcock mesh, changed the oil, fresh battery, etc. Got them cleaned out ok, but like an idiot, trying to remove a particularly stubborn float pin, I break the tower that holds it. No picture of that - too much swearing going on at that point. So I figure what the hell - I JB weld the tower back together, and button them up. The bike fires, but runs like crap. Won't rev past 4k or hold an idle. But it runs, dammit - so I celebrate with a few adult beverages.
Now I try to diagnose what's wrong. I replace the plugs, points and condensers - no difference. Replace the coils and plug wires (Dyna) - no difference. Compression check - all 4 are consistent and in good order. Starting to get frustrated, and now am thinking that the broken part may really be messing something up. I spy a set of rebuilt carbs in the for sale section here, and snag them as a last resort. What do you know - it fires right up, revs past 4k, and sounds great. In my excitement, I take it for a spin around the block - not realizing the tires were near flat. On my first ride on the bike, I kept thinking 'this thing handles like crap - what kind of mistake have I made?'. Get back to the garage, and after some air in the tires, I'm very relieved to find it handles just fine. Aside from a worrisome oil leak between the fins between 1 and 2 cylinders, I feel pretty good about the whole thing.
Here's where the project takes a turn... I look at the bike now that it's running. I think to myself that with just a little more work, I could really take care of all of the small maintenance items - wheel and steering bearings, brake rebuild, cleaning up/painting the motor, and giving everything a good cleaning. Besides, I really need to do some work on that oil leak. I promptly spend an afternoon doing the following:
Ok folks - now we're in deep. I look more closely at the motor, and try to figure out what's wrong. After asking on the tech forums, I'm told it's likely the 'puck' leak, and may not be the head gasket. Sounds good to me.
After reading up a bit on the process, and consulting the Clymer, I go for it:
