Topic: 1977 CB750F Cafe Racer "Red Rocket"

[andy750]

I used to have a red CB750 just like the last photo - was a great handling bike. Tall seat, great brakes etc...took me over to France and back to Scotland.

Good luck with the paint - the black mock-up shot looks pretty cool. I still like the red though.

And cool hair...he did a good job!

cheers
Andy

[rafanomenon]

Updated before and after shot. In photoshop, I shortened the front fender, dropped in some wheel accents, and drilled the rotors... ahhhhh to think this is where my bike will be in 2-3 months. can't wait to wrench this weekend!



full size photo here: http://www.rjrcreative.com/bike/?p=401

[SOHC4 Cafe Racer Fan]

Raf,

I like where you're going with this.  The Knucklebusters MC logo is cool. 

How are you going to form knee dents on a Benjie tank?  Are you having BCR do it beforehand?

[rafanomenon]

Raf,

I like where you're going with this.  The Knucklebusters MC logo is cool. 

How are you going to form knee dents on a Benjie tank?  Are you having BCR do it beforehand?

I plan on keeping the stock F-tank on there. I love the lines. I forwarded Benjie the photoshopped mockup. Hopefully he knows where I'm trying to go with it! I trust his judgement.. everything he does is kick ass.

The knucklebusters crew has a few spare tanks laying around. I feel like I've got a pretty good grasp at it.. I'll start out slow with different sized rubber mallets, working from the center of the dent outwards. Then bondo, sand and prime.

I'm trying to time it perfectly to finish the tank by the time Benjie's tail section arrives on my doorstep. Then it's off to paint. I'm thinking a hotrod flatz black. maybe some custom red pinstriping. I'll make sure to post progress here   

[Flying J]

did you see the pics of my tank with the dents? I just used a rubber deadblow hammer. pounded the dents in and then bondo. It didnt dent in how i expected. When i hit the side the whole thing flexed in. The side just collapsed in and then i pounded around the edges. its not finnished yet. Still have to sand and fill some more. Bondo takes forever and makes a huge mess.

[rafanomenon]

I just watched this video:

http://www.youtube.com/watch?v=ou-1adqRyVU

Maybe he just makes it look real easy  It's also a different tank with different geometry, so it bends different than an F-tank... we'll see how it goes!

[rafanomenon]

Alright, I made a little progress this weekend. I came home from work Friday and noticed a package. I won some R6 rearsets on eBay for $100, and I plan on welding brackets onto the frame to mount them. I did some mockups and have a good idea of how/where they're going to mounted. I just need another weekend, and a shorter swingarm and engine mount bolt for when I remove the ugly OEM aluminum brackets. I plan on buying a tapper/threader and cutting the stock bolts down to fit.

I also got got moving on pounding dents into my tank. I had a spare one laying around that my cousin ran over (boo) that had no business being used for anything else, so I practiced on that. I started by tracing a rough template, and pounding the middle going outwards. Some parts dented different that others. I made sure to note this for when I dent the real tank. The weird parts were the front-middle of the tank, and near the bottom.

I plan on filling the dimples and imperfections with bondo, then sanding and priming for paint.

[rafanomenon]

... and yet another tweaked image of what the bike will look like by July:



and a rough list of mods, both current and projected by July:

- Red Comstar accents
- Powder/Chrome Comstars (undecided)
- Chopped front fender
- Fork Brace
- Drilled rotors
- New headlight and mounting ears
- New upper/lower triple clamps
- New gauges
- 3-way adjustable clip-ons
- Cycle-X 4-2-1- Headers
- Earlier K-model carbs w/air pods
- Dyna S ignition, coils, d8ea-9 spark plugs
- Chrome valve cover, side engine cover
- Chrome swingarm
- R6 rearsets with welded brackets
- Reservoir shocks
- Custom BCR seat
- BCR Battery tray
- BCR oil tank
- Chrome swingarm
- Avon Road Rider tires
- Custom license plate bracket
- Custom paint
- 850 big bore kit (next winter!)

..... WHEW

[FunJimmy]

You're making great progress on the bike.
I really like the direction it's going.

I tried pounding knee dents in a rusty old spare tank too and the results weren't too bad.
You'll get a lot less denting and subsequent filling if you use a rubber mallet.
I took my rubber mallet to a belt sander and shaped one end like a sphere.

Good luck
FJ

[Flying J]

http://forums.sohc4.net/index.php?action=dlattach;topic=46035.0;attach=67294;image
look at these

[rafanomenon]

YES! that gauge is exactly what I want. Did you find out where he got it?

[Flying J]

after a little searching i found them! But WOW! $$$$$
http://newbonneville.com/html/lsl_tack_kit.html
alot of other real cool stuff on that sit too.

[rafanomenon]

OUCH!!! for some gauges?! I bet we could make something really close to that for no more than $100. that's just crazy.

[Flying J]

let me know if you make a set.

[rafanomenon]

I'm already searching for the supplies. So far, I'm up to $75 for the gauges. LEDs would run $10, and a day in a metal shop cutting some scrap. The nice chrome buckets in the back would be hard to keep cheap, but some scrounging at the salvage yard should yield some good results. It's possible for $100-$150 for sure. I'll let you know when I get around to it.

[FunJimmy]

You could make a two piece bucket using a appropriately sized tube and machined end cap.
Once chromed (separately) they could be bonded together with epoxy.

[rafanomenon]

Disclaimer: This isn't pretty 

Got started denting on the actual tank a couple days ago. As stated, it dented unpredictably using the orange deadblow hammer. I didn't notice how imperfect it was until I stripped and sanded.









Overall, I'm happy with the general shape and location of the dents, minus the bastard crease towards the middle-bottom, especially on the right side of the tank. I didn't want to overdo it, so I stopped. I don't think this tank is totally scrap - just a little more bondo and shaping work than I had originally planned. The dent on the left side looks different in the pictures, but it's just the direction that the light is hitting the tank. The shape is pretty symmetrical on both sides.





Bondo and general shaping tomorrow and Friday. Paint this weekend!

[rafanomenon]

Wow. Crazy to read up on all my past posts! I haven't posted here in awhile, as I acquired a 175 that I turned into a road racer. (I know it's not a SOHC4, but everyone likes pics!)



The 750 took a backseat, but is now being brought back to life. Here's what it looked like when I left off:



Here's what it looks like now:



I removed those ugly aluminum footpegs and plan on getting some MotoBits rearsets on there. I also ditched the oil tank, battery/tray, and plan on remounting the electronics. Where you say? Under my new seathump from BCR

Another mod I'm working on simultaneously is finding a compatible boxed swingarm from a newer sportbike. I don’t like the look and the sketchiness from the stock 750 swingarm, and the Dresda replica from Carpy is a little too rich for my blood. I plan on making some mods, which is no biggie. Here are some rough dimensions:



I slipped on some key measurements, like the diameter of the swingarm bolt, the rear wheel axle bolt, and the total length as I don’t want to sacrifice handling with an extended swingarm. I plan on making that measurement today and doing more shopping

I don’t mind doing some minimal mods, but I at least have to make sure the outside-to-outside length at the swingarm pivot and inside-to-inside length of the rear axle is close to stock. I plan on cutting off the shock mounts from the stock swingarm, and welding them into place on the new one. I also expect to have some offset issues, which I’ll solve by either shaving down the front sprocket shaft, inserting spacers at the rear wheel, or getting an offset sprocket setup from Cycle X. There has been some good feedback on the Honda Choppers and DTT forums that has convinced me this will work.. Or so let’s hope!

Here are my options:

1992 Nighthawk 750 Rear Swingarm (front runner)


Suzuki Katana 1100 Swingarm (this looks HUGE)


Kawasaki GPZ1100 Swingarm ZX1100 GPZ 1100 1995
(Seller is listing the chain adjusters separately for $49.99 boooo…)


Let's hear some feedback...

[Flying J]

you may have a problem cutting off the stock mounts and welding them on the new one. Most new swing arms a re aluminum. you may just have to fab up some new ones.

[rafanomenon]

you may have a problem cutting off the stock mounts and welding them on the new one. Most new swing arms a re aluminum. you may just have to fab up some new ones.

Yeah that's what I figured. I was originally going to drill holes through the swingarm, but I'm going the weld route. Don't have access to an AC/tig, so I plan on taking it to the metal shop down the street for some help.

Here are the measurements for the stock 750 F2 swingarm:


And the new swingarm I got for $50 shipped. It's off a ZX6R. Pivot measures 9″, and will most likely require shims/spacers. Inside length at rear axle measure approximately 10″. The stock wheel spacers and/or caliper mount will have to be machined down a tad to account for the smaller measurement. The length is approximately 21.75″, so it looks like I’ll only be rocking an extended swingarm of about an inch. I also plan on chopping and bolting a rear fender to the top of the swingarm.

(don't mind the redlines. That was still in brainstorm phase. I do plan on welding shock mounts onto the swingarm - Final answer)

[Aladinsane07]

Good to see you're back on the bike.  I like where this is headed 

[SoyBoySigh]

Go for the arm off the CB1100F. If you're so hung up on a boxed arm. The DOHC 750 arm is a popular swap, so you can see the geometry by looking at any of those bikes, and the 1100 is supposedly a straight bolt-up to the smaller DOHCs, so it should be the same type of deal. ME, I like the regular DOHC arm with a brace on it, that looks great to MY eye.

-S.

[Flying J]

Wow, really? Advice on a 2 year  old thread.