Topic: 1974 CB750 - Legacy Build

[Septavus]

So after lurking on these forums for awhile, and nearly 3 years of an off again, on again search for a bike, I've started my first rebuild/modification project.  While I've been riding and doing basic maintenance my whole life, this is the first time I'm attempting a frame up complete build.

My goals for this project are;

1. Have fun.
2. Learn a lot about one of my favorite past times, motorcycles.
3. Use this as a creative outlet from a extremely full, stressful professional life.
4. Do as much myself as I can, or I can attempt.  I only want to farm out work that needs super specialist skills or equipment for.
5. Try and include my kids, who already love bikes, especially washing dirty ones (very handy), and  encourage they're interest in the mechanical world.
6. Finish the project and have a well performing, safe, good looking bike for cafe club events, casual rides, and fun runs.  (This won't be my main daily rider).
7. Maintain this bike for the rest of my life.  It's not getting sold, and this is why it's taken me so long to find THE bike.

I was born in NYC in December 1974.  I've been looking for a CB750K, manufactured in the same month and year, 12/74, for the specific purpose of trying to keep it running for as long as I am. This is why I'm calling it a Legacy Build.  38 years later I find myself in Melbourne Australia, with two kids, and finally the time, money, and space to dive into the mechanical world through this rebuild.  So lets do this! 

Things this build won't be;
1. No time deadline (but would like to do in less than 18 months of weekend work)
2. No fixed budget (surprisingly I got the blank check from my wife)

Finding that specific month and year model took some doing, but about 6 months ago, I found one on eBay.  Through lots of questions, videos and emails, I ended up purchasing the bike, and having it shipped to Australia.  Whoa, sounds like a lot of effort, which it wasn't, but prices here in Oz on things like old bikes are kind of nuts, and it was actually cheaper to buy it and ship it.

Pictures Attached. (how do I embed the image?)

[Septavus]

More photos

[Septavus]

First things first after a good few washes, I needed a table to work on the bike, which I could move around.  So I built a workbench with some casters. (Casters and a Chock put on later.)

[lwahples]

Looks like you found a decent bike for your project.Blank check? Sweet!

[Septavus]

Be of no doubt, I'll somehow get the worse end of that deal in the long run, and blank has some limits, or some really creative accounting... 

[Septavus]

I changed the battery, emptied the gas tank (no rust signs at all), turned the key, and she started up after a few attempts.  Sounded a little rough but no major leaks, dents (outside of the tank) cracks etc visible.  Drained the oil, topped her up and tried again.  Then left her running for 5 mins, and even idled, reasonably well.  Pretty stoked for something I never actually saw and had shipped to the other side of the earth.  While I'm glad it worked, I'm still planning to fully rebuild the engine put in a bore kit, and do a number of internal upgrades.  And given all I've read on this forum, you never really know till you open her up...

So I prepared to do the teardown and got the following;

Downloaded and printed most of the manuals and schematics form here.
Have a Clymers
Couple different versions of wiring diagrams
iPad for reference to the forums etc.
Assorted Tools including impact driver
Plastic Baggies of various sizes
Some cardboard boxes for part storage
Assorted wire brushes, steel wool, fabric softener solution in a spray bottle.
Degreaser, Carb Cleaner, Penetrol etc etc
Camera
Jamesons
Ice

I started with the seat, then tank, then rear fenders, then straight into the wiring and electrics.  I took pictures for myself along the way of every wire, every step, every nut, screw bolt and washer.  Everything went into organised bags, labeled sorted and put aside.  I then edited some of the pictures and put labels on the actual pictures like the one attached.

[Septavus]

Kept going on the electrics, following up the frame to the coils, and then the headlight bucket.  Holy #$%* was that a rats nest.  While I expected it based on other pictures from the forum, it took me a fair chunk of time to trace, label, and ID each one, match them to the wiring diagram, understand what they were and what they did.  I know I could have just ripped them all out, given I'll likely replacing most of the wiring, but my goal here is more knowledge than speed.

[Tews19]

Welcome to the site and great project... To find a bike specifically to match your bday I am sure was time consuming.... Curious, if you do not mind, how much was shipping a bike to the land down under???

If the wires are intact and not hacked up from a PO, you will be surprised they tend to last and work efficiently.. Clean them up and put some electrical grease on them...

[Septavus]

Welcome to the site and great project... To find a bike specifically to match your bday I am sure was time consuming.... Curious, if you do not mind, how much was shipping a bike to the land down under???

If the wires are intact and not hacked up from a PO, you will be surprised they then to last and work efficiently.. Clean them up and put some electrical grease on them...

Thanks for the welcome.

Shipping from Kansas to California Long Beach was $300ish.  $900 for the 3 week boat in a container to Australia.  Then some taxes and customs duties once it lands. I've shipped a few bikes over here from home, and there's a reasonably efficient process.  Much easier for Pre 1989 bikes, but not hard for most others.  Need import approval etc. etc..

[SOHC4 Cafe Racer Fan]

If you intend to open up the motor, buy yourself an impact wrench/driver. Otherwise, you will strip the Phillips nuts.

[Septavus]

Well a terrible flu rolled through my family taking us all out for nearly 3 weeks.  Man these things are getting scary.  She's basically torn down to a rolling chassis with motor.  Just need to get the time to take the motor out now.  However while laid up sick, I realized I need to make a few decisions leading to next major steps.  Starting back to front, here's my first question / ask for recommendation.

I'm considering swapping out my swing arm for a slightly longer one, as the custom oil tank I'll be attempting needs a bit more room.  The oil tank will start flush with the back side of the triangle so that it's still completely clear, and curve upwards like the inner plastic fender,  I mocked it up with some cardboard and I reckon I need at least 2" more room, perhaps a touch more.

Searching the forums there seems to be no clear answer if this will impact the ride or performance of the bike.  Also given I have a 74' any recommendations, on longer other year swingarms, that won't be too difficult to fit?  Finally will this make any difference to my wheel selection or the rear brake as I'm considering a Disc swap in the rear.

Any help or recommendations would be appreciated, sorry for the noobish questions.

-Sept

[Tews19]

Longer swing arm will effect the handling..... Not sure but I think I read it will make the bike feel as if it turns slower.... I may be wrong... If you want rear disk.... Look into a 75-76 750 supersport set up....