CB750 Seven Fifty cafe-racer project begins.

 The source bike is 1992 Honda CB750 Seven Fifty we bought in the summer 2014. I don’t like idea to cut perfect motorcycle in good condition, so as for me, that was an ideal bike for full project, because it had only few undamaged exterior details.

This bike inherited:

  • Broken plastic parts mounted with cable ties;
  • Crumpled header pipes with anyhow welded and somehow mounted ugly mufflers;
  • Chinese plastic   headlight (light only formally);
  • Broken dashboard;
  • Brake disks, thin as sheet of paper;
  • Scratched engine covers;
  • All four footpegs were different one from another. And one of them was just a bolt, screwed into footpeg mount hole.

 And so on and so forth. Quite long list could be compiled, but bike was steel in rideable condition. So in the end of July 2014 one friend of mine brought it, riding it some 500km from another city and this CB750 occupied the corner in my garage for some time. Here is a couple of CB photos as it arrived to me.

IMG_3158 IMG_3147I had no time to make any movement of this new project until the end of March 2015. But I had time for thoughts, searches and researching. So I worked out some ideas about what to do.

IMG_6718Firstly I stripped off bike, cut off tail and passenger footpeg holders, took XJ600 51J tank from shelf and tried to install it on Seven fifty frame. It looked like it might be fitted, but with some light modification of both, frame and tank. Tank needed some deepening of tunnel, so I did it carefully with hummer and wooden spacers. I didn’t know precisely would this tank look good enough on this bike, so I left modifying of frame mounting points for later times and installed tank temporarily.

I also found funny exhaust mufflers on ebay and decided to use them in this project. Stock header pipes were in condition “nothing to lose” and I cut them without any regrets. They should be replaced anyway, but in cut edition still may be used as a model.

Next point was wheels. I don’t like alloy wheel and better prefer spokes. But in case of CB750 I had a goal to keep two brake discs and 17” rims applicable to stock tire dimensions . With some luck I found in sale at hand front wheel with old Suzuki style dual disk hub an 2.5” wide 17” aluminum rim. It needs to be respoked with new spokes but that’s not a problem. I had luck with rear wheel also. I bought a wheel from Honda Transalp 650 (2.5 inch wide rim ) with sprocket hub and dumper, and one of my friends had proper 4.25” wide rim I may take and try to fit. I temporary respoked Transalp wheel with this rim and it fitted perfectly. After that I had to do researches in front brake discs direction. I measured original brake disk, new hub and then found what type of discs will fit to both: new hub and old brake calipers. And what a luck again! I had such discs at hand too.

So, question with spoke wheels was mostly solved. There is still some work should be done about adaptation, but nothing special, just routing measuring and lathe works.

It seems to me, I wrote to much words again. Ok, let’s shorten this opus!

My next step was tail and seat modeling in first approximation. The way is well known, I took a sculpture clay and in several iteration found configuration I like. A couple of last touches: gaiters and clip-ons and everything is ready to announce my work on new project.

Yep, I must say, that I used tires I had at hand, and at least front should have less sharp pattern. And this is only the first step in cafe-racer creation, so nothing is set finally.

That’s all, time to photos:

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9 Comments

  1. Stewart

    Hi, I’m building a retro mod based on the same bike like you did.
    So did you mean the rear wheel from a transalp will fit prefectly on a cb750 with no modification needed?
    Will the brake disc fit as well and will it be prefectly in the center line of the bike?
    Many thanks

    Reply
    1. gazzz (Post author)

      Hi!
      Nope, it didn’t fit perfectly. Even if you leave original Transalp narrow rim, you should move it by spokes to center it. Brake disk have same mounting holes positions but also need a spacer. And, of course, all other spacers on wheel axle are different from original.

      Reply
      1. Stewart

        Thanks for replying
        Never tried re spoking a wheel, should be a plain in the ass…..

        Reply
  2. matt

    Hello there.

    I have a 1992 cb750 and looking to convert to spoke wheels. Do you know which model front wheel you used to keep the twin disc setup?

    Thanks

    Reply
    1. gazzz (Post author)

      Hi!

      The hub of the wheel looks very similar to old Suzuki GS750 or GN400 one. Spokes are just a poor quality stuff and rim have no marks except width and diameter indication. So I guess it is a repack of Suzuki hub with new rim. The only weak point is spokes so I ordered new set and a wheel is ready to be repacked again after I’ll decide in what colours paint its parts.

      Reply
      1. matt

        Thanks for the reply! I really love to look of the spoke wheels so I’ll have to have a look around and see what I can figure out!

        Reply
  3. Simon Fridh

    Hi. I’m doing a cb750 -81 project, and just got my hands on a complete -98 fork. Better suspension and brakes than original.
    I also prefer spoked wheels and that hub shouldn’t be too hard to find. But what brake discs did you use? And did you have to use spacers for the front discs?

    Reply
    1. gazzz (Post author)

      Hi!

      Brake disks may be used from the following Yamaha motorcycles: TDM850 (4TX,3VD,4CM), TRX850, XJR400, FZS600 Fazer (RJ02), FZR600 (3HE,3RG,3RH,4JH,4MH) and so on.

      Here is information about spacers:
      http://www.gazzz-garage.com/2016/06/07/seven-fifty-cafe-racer-chassis-adaptation/

      Reply
      1. Simon Fridh

        Thank you!

        Reply

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