Topic: Not Another Cb750 Cafe Racer?!?! - 1972 CB750 Project

[Parkwood60]

It has been a seriously long time since I have even lurked on motorcycle forums. Iused to be a regular on both teh VJMC and SOHC4 emailing lists years ago. But, I was down to ZERO running, registered street bikes and concentrating more on racing my 24 Hours of Lemons car for the past 4 years. I didn't wanna hang out on a Cafe Racer (or any motorcycle) forum and be just another poseur without a bike.

But, after about 10 months of disassembly, cleaning, painting and reassembly I finally have a bike to ride, and something I feel I can show off on the forums. This is my 1972 CB750. I've owned it since 1994 (20 years now). I traded my first bike for it (1969 CL450) in Boston, rode it cross country, used it as a messenger hack in L.A. for years, and finally retired it when the 4th motor got tired. I would guess the only thing left from the original bike I started with is the frame.





Before and after pictures, as well as during here: http://piledriverz.com/2013/11/03/honda-cb750-cafe-resurection-continues/, http://piledriverz.com/2013/11/09/cb750-cafe-racer-resurection-part-2/, and http://piledriverz.com/2014/05/18/its-not-finished-but-its-done-honda-cb750-cafe-racer/

Huge facebook photo album of project pictures here - https://www.facebook.com/media/set/?set=a.504506666297478.1073741829.143772792370869&type=3

Its not done yet, but at least I can ride it all summer while the last pieces of the puzzle come together. What do you think?

[goldarrow]

I like those pipes and brownie tank with glitters. Not sure if front comstar matches with rear spokes. 

[Parkwood60]

Yeah, that is the biggest thorn in my side at the moment. I am getting other discs machined to bolt up to the original spoked hub, but work with the more modern calipers. I am still debating getting spacers made for some really modern discs (I think they are Yamaha R6), or getting the center of a pair of Suzuki GS1000 discs opened up to fit the Honda hub. Both sets have the correct 6 bolt pattern to bolt on.

[Tews19]

That is one funky header! Any way you can take a pic from up front?

[Parkwood60]

That is one funky header! Any way you can take a pic from up front?

The front half is a vintage Triple A header, I cut it at the collector, pie sliced it, and welded a megaphone and bit of pipe from an unknown GS1000/750 pipe that was just taking up space. Here's a picture of it as it originally looked.



Here it is again before it got glass beaded and painted high temp gloss black



Here's a better picture of the front of it

[Parkwood60]

I'm not a loud pipes guy, but I felt like I needed a loud option for when I am going to hang out with the other trendy bikers in L.A. at all the trendy biker events.  So I made a baffle free reverse cone for my megaphone.

1972 Honda CB750 cafe racer reverse megaphone

[Parkwood60]

Haven't done a whole lot since the last post, been to busy riding it. I did however wash it this weekend. Then I pulled the carbs off and adjusted the needle 1 position richer. They sure don't make it easy to get in there, do they? The carbs have to come off the motor and then off the piece that holds the 4 of them together to get the slides out. Anyway, before the adjustment it seemed to have a bit of a lean surge while cruising on the freeway at 5000rpm, but was great at WOT. Now it seems to have smoothed out all through the mid-range as well. Success!

No pictures of taking the carbs apart, but here's pictures of it clean.

[calj737]

Uh, not to put you down or anything, but has no one pointed out to you that the right side tank badge is upside down? Or is it intentional eccentricity that drives your build  your tank looks to be a bit battered and wavy too. Is that an odd reflection, or years of street use?

If you want it straightened out, find a good local Paintless Dent guy and they should be able to push those out for you and give you back a straight piece of metal without damage to your now, beautiful brown glitter.

[Parkwood60]

No, the tank is straight except for 2 dimples in the front to allow the 982 CB900F fork to turn to full lock. It's just the way the light is on it in the picture. Between the reduced offset of the clamps and the increased diameter of the tubes it was that, or lose some parking lot maneuverability.

Of course I know the emblem is upside down. You'd have to be pretty stupid to screw up something like that.

[SOHC4 Cafe Racer Fan]

Parkwood,

What's going on with the starter?  An earlier picture shows something red strapped in place of the starter.

[Parkwood60]

What starter? That's where the battery lives now. It is orange. Why would I need a starter when I have 2 perfectly good legs?

There are lots more pictures and stuff at the links in the first post

[SOHC4 Cafe Racer Fan]

Without looking at the links, it looks like a 1972 CB750K frame/engine with a 77-78 CB750F front end and wheel, and a F-style gas tank. 

I like the drag style bars. 

This looks like a fun, no fuss bike.  Any mods to the engine besides the finned covers?

Any particular reason to contrast the brown metallic tank and fender with the silver side covers (is that just a particular color combo you like)?

[Parkwood60]

The bike as you see it is at an interim stage. I got it to the running, riding, looking okay place its at now and stopped so I can ride it all summer. It is a bone stock motor with about 25k miles on it. It runs okay, but seeps from under the cam towers a little, and has at least 1 bad valve seal. But I have 3 other motors I am making 1 good, higher performance big bore one out of. One of the side covers is cast aluminum, the other one I painted metallic silver for now until I can find a mate for it, or afford a pair of new aluminum ones from Cycle X or India.

Its actually got a 1982 CB900 39mm fork and 2 piston brakes on it right now. I haven't decided which front brakes & calipers I am going with, but I need to do a little machine work to fit them to the spoked wheel that matches the rear. It needs new rear shocks too, but the ride height will stay the same, these are from the DOHC CB750.

The drag bars may go away when I fit the Rickman style 1/2 fairing to it and take off the train light.

[calj737]

Of course I know the emblem is upside down. You'd have to be pretty stupid to screw up something like that.

So it is intentional eccentricity. Excellent! Carry on.

[73seebee5]

Run what ya brung.
I feel it.
I love it.
Keep us updated.

[Parkwood60]

Working currently to mount dual Suzuki GS1000 discs to the stock early Honda CB750 spoked wheel hub to work with the later CB900f front fork and 2 piston slider type calipers. After a minor machine operation to open the center up about 1mm, it looks like I just need an 1/8" spacer for the caliper mount, and the typical dual disc speedo drive modifications. I will post a more detailed version with pictures when its done.

[SOHC4 Cafe Racer Fan]

Working currently to mount dual Suzuki GS1000 discs to the stock early Honda CB750 spoked wheel hub to work with the later CB900f front fork and 2 piston slider type calipers. After a minor machine operation to open the center up about 1mm, it looks like I just need an 1/8" spacer for the caliper mount, and the typical dual disc speedo drive modifications. I will post a more detailed version with pictures when its done.

Here's to another K bike with an F tank!  (I prefer the lines of the SS tank.)

You've had a ton of history with this bike.  When you bought it in 1994, it bet it was dirt cheap, as the market then for CBs was weak.  You must have packed on miles using it for courier service.  How many miles did you average per motor?

[Parkwood60]

The first motor was pulled at about 40k miles because the oil leak from the rubber pucks in the top end had gotten un-managable. All the other motors were unknown mileage. Pretty sure this is the 4th motor in it now. I know 1 motor suffered top end oil flow issues and died. One was just plain worn out and blowing smoke, but still ran just fine (I suspect valve stem seals). I'm sure there was another motor that broke or something, but I don't recall what happened to it. I do know I had one eat 2nd gear and I managed to split the cases and swap out the messed up parts over a weekend.

I didn't pay for it. I did swap a much cleaner low mileage 1968 CL450 scrambler for it, which I paid $300 for. It was not much to look at, but it ran fine and was a much better touring machine than the CL450.

[SOHC4 Cafe Racer Fan]

The first motor was pulled at about 40k miles because the oil leak from the rubber pucks in the top end had gotten un-managable. All the other motors were unknown mileage. Pretty sure this is the 4th motor in it now. I know 1 motor suffered top end oil flow issues and died. One was just plain worn out and blowing smoke, but still ran just fine (I suspect valve stem seals). I'm sure there was another motor that broke or something, but I don't recall what happened to it. I do know I had one eat 2nd gear and I managed to split the cases and swap out the messed up parts over a weekend.

I didn't pay for it. I did swap a much cleaner low mileage 1968 CL450 scrambler for it, which I paid $300 for. It was not much to look at, but it ran fine and was a much better touring machine than the CL450.

I agree.  The Honda 450 is a great motor, but not exactly the best displacement for touring.