Topic: Bought my first CB750 - Advice Needed

[BSAKat]

Hey, friends. Like it says on the tin, I just picked up my first CB750. Well, two of them, to be precise. I bought a pair of '75 supersports out of a guy's backyard where they'd sat for 20+ years. They're both disasters, but they're complete (despite what the rolling frame looks like, I have everything to put it back together) and came with titles. Here they are:



Here's the thing, I don't know anything about 750s. I have experience restoring CB200s, CB450s, and CB500/550s (I currently daily a '72 CB500) but the 750 is an entirely new animal for me. Added to that, I know the F-model supersports are different in a few ways than the K models so that complicates matters. Aside from normal rescue/resurrection stuff, what CB750-specific things do I need to look out for when wrenching on these?

[BigJimG]

Hopefully the turn signal bracket is still under that windjammer and unmodified if you're planning on pulling it, but at least it looks like it's intact on the other one.  Unfortunately, the unique F model parts are getting slightly harder to find, but they're out there.  I must have missed these, as I usually search the Detroit Craigslist pretty regularly especially for F models. 

[Maltboy]

Download the shop manual and the parts manual. Both are available from this forum. Look for the sticky 'Download Motorcycle Manuals'

[Alan F.]

That's a great find, two 75 F-bikes with titles. 75 was the only year F with a spoked, disc brake rear. So that's another sought after item, tanks seem to be getting harder to find these days too so hopefully they're not Swiss cheese... Your 450 experience should serve you well as many things will seem familliar, but the engine will not challenge you like a 450/500 could. It's just more parts, not more complicated.

But I'm a K bike guy...thanks Newday777

Edit: WELCOME!

[bryanj]

Mechanical wise if you have done a 500 you can do a 750 its just heavier and you have to pull the engine to do a top end, get Hondamans book and the only special tool are a rotor puller and a clutch nut spanner.
Cleanliness on rebuild is a must especially on oil feed to head and NO RTV anywhere.
Manuals are on line but you need the original 750 with the supplements up to your model which list the differences

[ekpent]

Hopefully the turn signal bracket is still under that windjammer and unmodified if you're planning on pulling it, but at least it looks like it's intact on the other one.  Unfortunately, the unique F model parts are getting slightly harder to find, but they're out there.  I must have missed these, as I usually search the Detroit Craigslist pretty regularly especially for F models. 

The turn signal stalks have been cut off the rolling frame bike and I would bet a dollar that the headlight frame on the Vetter bike is either missing or the stalks have been cut off that also. 2 year only part so you will probably be putting that on the want list if you go naked.
  Is the engine turning free right now on the blue bike or froze up.  If those luggage racks are hinged to get out of the way of the tail cowl they are kind of hard to find for people that want one. Working on them is not much different then the smaller 4's.

[BSAKat]

Hopefully the turn signal bracket is still under that windjammer and unmodified if you're planning on pulling it, but at least it looks like it's intact on the other one.  Unfortunately, the unique F model parts are getting slightly harder to find, but they're out there.  I must have missed these, as I usually search the Detroit Craigslist pretty regularly especially for F models. 

Oh, these weren't on CL or Marketplace. They weren't even for sale. I spotted them in the guy's yard because said yard backs up to an alley in Ferndale I was driving through. I walked up, rang his bell, and offered him $800 for the whole shebang. He took it and here we are. The stock turn signal bracket was included in the parts pile, thankfully. There's also a Windjammer IV with a sound system and a security system that was on the stripped bike and an OG Hondalite vacuum set for syncing the carbs.

Is the engine turning free right now on the blue bike or froze up.

The blue bike's engine is stuck and the other bike's engine is in pieces. Once I get the bikes home Saturday I'm gonna pour some juice down the bores in the blue bike and see what happens.

Thanks for all the info, fellas. I appreciate it.

[Alan F.]

I love these stories, especially when the bikes have titles and 'hidden bonuses'. Plus you probably helped the guy out some, good Karma goes a long way.

I can't wait to hear what's behind the points covers.

[BSAKat]

I can't wait to hear what's behind the points covers.

I'm guessing a colony of spiders.

Oh, I forgot to ask. Are these engines wet sump or dry?

[bryanj]

Dry sump, oil tal bolted to frame on rh side

[754]

 I hope that oil cooler did not get water in it and freeze..
 Have fun with those bikes.?

[newday777]

75 was the only year F with a spoked, disc brake rear.

Actually 75 and 76 had spoked wheels with disc.

77 and 78 had comstar wheels.

[newday777]

Oh, these weren't on CL or Marketplace. They weren't even for sale. I spotted them in the guy's yard because said yard backs up to an alley in Ferndale I was driving through. I walked up, rang his bell, and offered him $800 for the whole shebang. He took it and here we are. The stock turn signal bracket was included in the parts pile, thankfully. There's also a Windjammer IV with a sound system and a security system that was on the stripped bike and an OG Hondalite vacuum set for syncing the carbs.

Is the engine turning free right now on the blue bike or froze up.

The blue bike's engine is stuck and the other bike's engine is in pieces. Once I get the bikes home Saturday I'm gonna pour some juice down the bores in the blue bike and see what happens.

Thanks for all the info, fellas. I appreciate it.

Great find with all the parts. Did you say he was the original owner? Did you get the story on them?

The oil tank is behind the right side covers.

Have a blast bringing them back to life! They aren't too complicated. The 75 and 76 F Super Sport used the same motor as the K models.

[newday777]

I can't wait to hear what's behind the points covers.

I'm guessing a colony of spiders.

  good reply!

If you haven't looked at http://www.honda750expert.com/ this will show and describe the differences.

[Alan F.]

I can't wait to hear what's behind the points covers.

I'm guessing a colony of spiders.

  good reply!

If you haven't looked at http://www.honda750expert.com/ this will show and describe the differences.

Yeah, I was thinking electronic ignition or points. You're not going to find an infestation in there consisting of anything larger than that tiny drain hole will let in.

[BSAKat]

Hah! I knew what you meant, I was just being facetious. I'm bringing them home tomorrow, so once I get 'em off the trailer I'll shoot a bunch of photos and post them here. Until then, enjoy these shots of the parts and accessories pile I brought home already:

[bryanj]

 You would get a good chunk of what you paid back just for the vacuum gauges

[robvangulik]

He'll have to use them first I think

[Alan F.]

Found one on ebay:

https://www.ebay.com/itm/HONDALINE-VACUUM-GAUGE-4-Dial-Gauges-NOS-with-Instructions/294037557666?epid=1330043896&hash=item44760111a2:g:GBAAAOSwww5gOzJL

[bryanj]

Im sure the last set i saw on ebay went for nearly double that

[BSAKat]

Okay! I got the supersports home this morning and did some more shooting for you all. The blue '75 is, in the words of a late Soviet nuclear technician, "Not great, not terrible." The roller, a formerly sulphur yellow '76, is all terrible. I've decided to rescue the blue bike and use the other as a donor. The blue bike is shockingly complete, as you'll see in the following photos. The exhaust is obviously beyond saving (well, the silencer is, at least), every piece of rubber needs replaced, the engine is currently stuck, the brakes are shot, and there's lots of surface rust, but I'm in love. So, enjoy these pictures and feel free to laugh at my ridiculous hubris.

You're finally home, friends. No more suffering.




The paint on the tailpiece looks fantastic, all things considered. The tank less so, but I think with some proper cutting and polishing I can bring it back to a respectable shine.





R U S T Y. As you can see, the silencer is completely shot. The head pipes are fine at first inspection, so I'll probably be able to save those and just hack that silencer off and replace it with something new.


Surprise! There's 3/4 of a tank of 35-year-old gas in there! You can imagine how this smelled when I opened it, and the top of the inside of the tank is rusty as hell. That's gonna be a real issue going forward, but at least I know the tank isn't rusted through/doesn't leak!





Right? Right!? It still has its tool kit and its owner's manual. The bike sat outside, uncovered, for 30-some years and that owner's manual is in fantastic shape. The battery less so, as you can see.



Finally got that damned fairing off and my shop assistants were very excited to give it a shakedown. Someone mentioned upthread about the headlight/turn signal bracket. I have a complete one for the blue bike, thank god, along with the headlight bucket and everything else I need to reassemble it.


Mmmmmmm, scotch locks. The sign of quality. You know you're in for a real good time when you find those things in your loom. Whoever installed the fairing is responsible for that.


There it is in its new home. You're safe now, friend.

So, there you have it. There are two bikes ahead of it so it'll be at least six months before I can dig in. That gives me plenty of time to source parts, get that engine freed up, and make a serious plan for it. As it stands now the plan is just to get it back on the road and ride the wheels off it. I'm also hoping to make a video series for work of the restoration process, so I'm currently sourcing sponsors.

[MauiK3]

Wow, looks like a fun journey has begun.
Hondaman’s book is a must, read it before you start, it will save you much pain. You will be more confidant.
Don’t let an automotive machine shop do your head and cylinders, Hondaman did mine. Be careful to keep the carb parts together, avoid mixing parts.
Yamiya is a great source for parts, high quality.
Looking forward to following the project.

[MauiK3]

If you want to read a great restoration thread of a rare K0, read Markb’s thread of his restoration of Sandcast number 97, it’s a great read and very informative.
The bike spent a year in the Peterson museum.

[bryanj]

Couple of tins of Heinz and some wire and that exhaust will be fine😂
Scotchlocks are what the fairing supplier gaveyou in the fitting kit.
One of the hardest bits to find is the square section O ring sealing the fluid path between the two halves of the back caliper

[Maltboy]

It's incredible the owner's manual survived that long outdoors.  Cool stuff.