First set of parts purchased for the rebuild…
First set of parts purchased for the rebuild…
MotoChannel did an awesome video for SOHC forum member CB750 Cafe Racer Fan’s Nine Lives bike. You can check out his entire build thread here. Amazing transformation. Amazing build.
temptingtimeonimpulse said: Hi I jut picked up a '76 Honda cb750f super sport and I plan on rebuilding it. The problem is, I have no idea how or where to start. Do you have any pointers on how to begin? Btw I'm Emmanuel
Congrats on getting your hands on an amazing bike, brother. I love the Supersports & think now I’d go for a ‘77 or ‘78 750 Supersport if I came across one.
Where & how to start depends on the bike’s history & its condition. If the bike doesn’t start, you’ll have to start learning what’s necessary to get a bike in running condition; you’ll have to go into detail learning about spark, compression, & fuel. If the bike is starting, download this CB750 Shop Manual (you should do this regardless of your situation) & run through the 3000 mile tune up procedures for your bike. Once you’ve worked through the tune up procedures, put about 100 miles on the bike & see what should be fixed from there, all the while reading your SOHC forums to learn how to look for issues & troubleshoot them.
Best of luck, Emmanuel. Have fun & stop by any time you need help. I may not have the answer, but I guarantee someone on the forums will.
P.S. Find yourself a good JIS screwdriver & JIS impact driver. Both will save you a lot of headaches over stripped screws.
So I haven’t done an excellent job explaining what’s going on with the bike right now or posting progress. The bike started leaking oil from around the #2 & #3 exhaust collars on the engine. I was also getting a blue tint of smoke out the exhaust at startup, but it seemed to die down while riding. I was losing oil fast & because I couldn’t get access to a compression tester, I decided to move forward with rebuilding the top part of my engine.
In the above photo you can see beyond the leak down to the valve. The valve has an unusually white coating. Exhaust valves 1, 2, & 4 have this white coating, suggesting the bike has been running lean, but valve #3 is dark. I don’t know if this is from my rides or from the previous owner running it lean. I’ve covered every base I know in regards to carbs, but will do another thorough check since the carbs are already off the bike now anyway.
Here’s a shot of the oil sitting in my pipe after a ride — evidence that this is more than just an old, leaky head gasket failing to do its job.
Here’s my #3 spark plug. The other three plugs look normal, while this plug has a much darker coloring & even appears that it’s been wet. See this thread on the SOHC forum where my mate enwri gives a great explanation of possible causes.
After a lot of PB blaster & some very gentle mallet & putty knife work around the old gaskets, I got the head off yesterday. Below are a few more photos of the process.
Note here how three of the four exhaust valves are brownish in color. These match to the same valves that are white. The odd, dark exhaust valve matches with the odd valves I mentioned above.
"There is something about coon hunting that helps a fella to keep his priorities in order. Coon hunting was a year round sport enjoyed by J.D. Bonds, the two old men Wards, myself and some of the other young boys. When the dogs would tree a coon we cut the tree down and chopped it open since it was normally hollow. This freed the coon from his safe haven and to get away, it had to whip about a half dozen dogs. This gave the coon a fighten chance. All dyed in the wool coon hunters throughout the south felt the coon should get that chance.
A lot of the women, including Mama, worried about us stepping on snakes since the hunting was mostly at night. The men were not as scared and felt that snakes should look out for themselves.
One of J.D.’s dogs won top honors at a national coon dog trial. Shortly afterwards a chauffeured limousine pulled up in front of J.D.’s house and an oil executive got out and announced that he had come to buy the dog, that he didn’t have time to haggle and that J.D. could name the price. When J.D. told him the dog was not for sale the executive remarked “every thing has its price”. The limo left without the dog. J.D. enjoyed a lot of coon hunting before the Lord took him.
Some years later I took a course in psychology at Florida State University where we spent all except the last day studying the hang ups and problems that people have. The last day we were to list all the traits of someone that had it all together and was well balanced. When we were to try to think of a person that fit the profile, I thought of J.D.” - A short account from my grandfather, Marcus Bartlett
Uncharted territory. The final frontier.
"The moral significance of work that grapples with material things may lie in the simple fact that such things lie outside the self. A washing machine, for example, surely exists to serve our needs, but in contending with one that is broken, you have to ask what it needs. At such a moment, technology is no longer a means by which our mastery of the world is extended, but an affront to our usual self-absorption. Constantly seeking self-affirmation, the narcissist views everything as an extension of his will, and therefore has only a tenuous grasp on the world of objects as something independent. He is prone to magical thinking and delusions of omnipotence. A repairman, on the other hand, puts himself in the service of others, and fixes the things they depend on. His relationship to objects enacts a more solid sort of command, based on real understanding. For this very reason, his work also chastens the easy fantasy of mastery that permeates modern culture. The repairman has to begin each job by getting outside his own head and noticing things; he has to look carefully and listen to the ailing machine.
The repairman is called when the smooth operation of our world has been disrupted, and at such moments our dependence on things normally taken for granted (for example, a toilet that flushes) is brought to vivid awareness. The repairman’s presence may make the narcissist uncomfortable, then. The problem isn’t so much that he is dirty, or uncouth. Rather, he seems to pose a challenge to our self-understanding that is somehow fundamental. We’re not as free and independent as we thought. Street level work that disrupts the infrastructure (the sewer system below or the electrical grid above) brings our shared dependence into view. People may inhabit very different worlds even in the same city, according to their wealth or poverty. Yet we all live in the same physical reality, ultimately, and owe a common debt to the world.” — Matthew B. Crawford, Shop Class As Soulcraft
This is one of the most powerful things I’ve read all year. I’m enjoying this book a lot & can’t recommend it enough. I’m sure I’ll be writing much more about it as I work through it.
Last night I went to the vintage bike club meetup in Happy Holler, Knoxville, TN at Time Warp Tea Room. Time Warp is a coffee shop with tons of old bike culture memorabilia. The club meets there every Tuesday night. It’s a lot of fun & most of the members are older guys that have worked on vintage bikes since the bikes were first introduced. Members have done just about everything — raced all over the world, been mechanics, painters. One of the co-founders told me last night the only place no one in the club has raced is on Bonneville salt flats. I’m planning on becoming a regular; too much wisdom floating around those parts to pass up.
Guys, it’s not rust. It’s patina. Thx.
Here’s my short list of top end engine rebuild parts. I may or may not get all of these things.
Cam cover gasket, …
Cometic head gasket, 48.23
Cometic base gasket, 12.52
OEM piston rings, 32.40 each (need 4)
KPMI Valve stem seals, 39.92
Tsubaki cam chain, 32.51
APE heavy duty studs, 77.31, 3 step retorque to 22 ft-lbs. Torque, let sit overnight, then come back & retorque.
Cam chain tensioner, roller, & guide, 99.95
Cylinder head rubber seals, 3.38 each (need 6)
== $467.08 for parts alone.
Also, engine cover screw sets, 36.90 + shipping
Plus expenses of having cylinders miked, valves lapped (may do myself), & cylinders honed or bored. Depends on the damage.
I’m sure there are a bunch of o-rings I’ll have to replace. Hopefully at minimal expense.
PS: Some tips… Use parker o lube to lube o rings, use hylomar on pucks, use Hondabond or equivalent between crankcase halves, all other gaskets are installed dry. Use a flat steel ruler to make sure cylinder & head mating surfaces are flat. If not removing bottom end, at least pull oil pan & clean screen to oil filter & inside of oil pan.
SOHC Forum tips for installing new studs in your engine:
"Lets install some APE heavy duty cylinder studs. I have decided to use some suggestions from MReick. I am using his procedure to install these and NOT following the instructions provided by APE.
1. CLEAN YOUR HOLES OUT!!!
Make sure your threads into the engine case are clean! I used a M8 x 1.25 thread chaser, barrel brush, WD-40 and compressed air to clean everything up. Spray the threads with the WD-40 and then run the thread chaser (or bottoming tap if you prefer) through each hole. Then blow each hole out. Respray with WD-40 then push the barrel brush in the hole and then twist it anticlockwise out. Blow everything out with the air.
2. INSTALL YOUR STUDS!
This is where things get different from the APE directions. Apply the red Loctite to the long end of the cylinder studs and thread into the case. If you don’t have a stud installer just use two M8 x 1.25 nuts and a washer between them to install the studs. APE recommends to install the studs with oil until they bottom out and then torque to 8 ft lbs. I just used red Loctite and installed the studs until they bottomed out and then lightly snugged up. If down the road you need to remove the studs just use heat.
*** WARNING ***
When installing the two cylinder studs with the oil feed holes be sure not to plug the small oil feed holes with loctite. Apply the loctite with a toothpick, and very little of it. Once the two studs are installed blow compressed shop air in the oil gallery via the oil pressure sensor hole. Verify the holes are clear by the air that shoots out of the stud oil holes! Making sure the holes are not plugged is VERY VERY important.
3. CYLINDER & HEAD MOCK UP
Without the gaskets installed and the pistons removed slide the cylinders over the studs and onto the engine case. MReick suggested to use a couple layers of paper towel between the head and jugs to compensate for the thickness of the gaskets. So I trimmed a shop paper towel doubled over and laid it between the surfaces. Now slide the head over the studs and install your cylinder stud washers and nuts. Mike made sure to tell me ” don’t tighten the nuts to tight” so I just snugged them up enough to put some pressure on everything.
4. THE CURE
Now just chill out and wait 24 hours for the loctite to cure and setup.
Now is a good time to remove the four cam tower studs on the head and install the Permatex Thread Sealant to the threads. The holes where these are installed are open to atmosphere and can be a source for leaks if not sealed.”