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CB750 cafe racer or rat bike or bobber project

Discussion in 'Modifications and Projects' started by maduncle, Jan 13, 2011.

  1. Hi all,

    You can already tell how well this project is going to go by the fact I have no idea how it will turn out.

    The starter bike - a 1977 CB750F I picked up off eBay last week.


    Runs well and is 90% there for a RWC, so first things first - get it (and me) back on the road. Given my last bike was a 2001 VFR800 used daily for work for two years, and I have now been two years off a bike since then - I want to get the feel of two wheels and some cc's under me again before I pull it to pieces.

    The plan is to get the small dings out of the tank, strip off the paint, polish the bare metal and clear coat it. Remove the side covers, relocate the battery and hopefully the oil tank. Fit new handlebars (clip ons or otherwise) and get a new seat, I kinda like a saddle but it may not suit. Then get smaller headlight, gauges and indicators, cloth wrap most of the exhaust and tidy it up.

    Inspiration is drawn from Bike Exif, Deus, Wrenchmonkees (11) and the Modern Motor Cycle Company here in Melbourne.

    If anyone out there knows places for CB750 parts, or for rat bike/cafe racer parts here in Australia, please let me know.

    More pictures as the build slowly progresses.

    ~ maduncle ~
  2. Looks like a pretty straight base!

    Clip-ons; drop the headlight down a bit; get a cowl for the rear end and a single seat; a fresh coat of paint and some racing stripes - and you're be cafe racering in no time!
  3. Update:

    Fixed a few minor problems with the bike on the weekend (lack of horn, broken brake lever, missing split pins) and took it round the block a few times, felt great to be back in the saddle.

    First thing I need to do is get a stainless steel triangular plate cut to cover all those ugly electrics on the left hand side where the plastic side panel once sat. the right hand side will look okay if I clean up the oil tank. I am also thinking of getting a triangular leather pannier made to fit over the plate, about an inch deep, big enough for keys, phones, wallet etc. Might as well use the space and a leather pannier might look the part.

    As for the front of the bike, I would love to find a full set of front forks with triple T's and use that to start a new front end rebuild, with clip ons, smaller gauges, new light panel in flat sheet steel, smaller headlight and small indicators. I figure if I build all this on another front end it will be easier to swap the assembly across.

    Anyone know where I can pick up a fork set in Victoria?

    Also chasing a seat from DimeCityCycles, they have a sweet one piece leather look seat that will fit the original tank. And the tank will be stripped back to raw steel, have a white stripe with pin stripe detail down the centre raised section and then clear coated.

    As for the wheels, finding older spoked wheels may prove challenging so I am looking at either painting the ones I have black or finding a metal spinner who can spin up discs to go on either side of each wheel, they would bolt up easy using the existing hub bolts.

  4. Looks like a good project mate, keep us to date!

    With the forks, if you just need the stanchions, try these guys: http://www.motorcycle-parts.com.au/Std_Fork_Tubes.htm

    There in QLD, but they're very good to deal with & have good freight rates. I think they quoted me around $550 for a set of stanchions for my TRX, the CB should cost less I reckon...

    Otherwise, you should be able to find a more up to date set of forks that will go on, there's plenty of info out there about cafeing CB's.
  5. Thanks for the tip,

    It is not so much forks, as a top triple T I am after so I can build a new front end 'off line' (set up new instruments, headlight, etc).

    Meanwhile - I made a cardboard mock up of the pannier on the left of the bike to replace the plastic side plate. Looks a bit stark in white so try to imagine it in dark brown leather...


    Next step - get the leather pannier stitched together.
  6. Quick question:

    Anyone know what I can do to replace 1977 truck sized rectifiers and regulators with smaller ones? I need to make some space on the LH side to get the stainless plate on without it sticking off the bike too far and if I can use new electric parts to make space it will help.
  7. I should call this the CB750 'tinkered' project, as it won't be all chrome bling and 'Happy Days' paint job like a cafe racer, and it won't be all minimalist and Bauhaus like a Wrenchmonkees project bike, it will be a modified bike with ideas from all the bikes I see.

    So yesterday I fitted the stainless steel triangular plate over the electrics on the left hand side. A bit of component relocating, a bit of bracket making and a bit of plate fabricating (I covered the inside of the plate with adhesive felt to insulate it in case it shorted any of the electrics out) - and now I have the plate bolted on.


    I like the simple finished look, but I still might put a leather pannier over the top of it. It will look better once the tank is stripped back and polished to match.

    Meanwhile - I am slowly gathering parts so I can build a new triple T assembly with a smaller headlight, clip ons, smaller gauges and a custom warning light facia.
  8. Good stuff mate, nice base to work from. Mightn't be the best handling or accelerating bikes but when you're done with it, it may well be one of the best looking.

    Check out dotheton.com if you haven't already, plenty of info and inspiration.

    Cheers - boingk
  9. Good luck riding in crosswinds if you try this.

    I've seen Comstar equipped bikes converted to spokes using suitably drilled rings that bolt to the hubs where the Comstar spokes bolt on, laced to normal spoke rims. A relatively easy job for anyone with a lathe, if you can find such a being. A small price to pay for getting rid of such horrible wheels (heavy, ugly, hard to clean and crap in crosswinds).
  10. Thanks for the dotheton link Boingk, I can see where I will be tonight.

    And PatB, good point about cross winds. I would love to find a good set of wire wheels for this bike, but I don't know how long that will take. Meanwhile I may just paint the fivespokers black for now (so I can pretend they aren't there). I looked into the disc idea - waaaaay expensive for four disks, I think I could buy another bike just for the spoked wheels for less!
  11. I went to start the bike today and it would not start, no spark at all.

    So I decided - bugger it, if it is not going and I can't work out why, and therefore I can't ride it in for a RWC before I modify it, then I am pulling it to pieces and getting right stuck in to modifying the bike before I ever ride it.

    Of course that all makes perfect sense doesn't it?


    Now I need to work out how much I can do (seems I am pretty good at pulling bikes apart) and how much I will need 'proper job' done by others.

    And now it is looking like this, I am tempted to have a go at hiding all the stuff where the battery and oil tank usually is.

    Things I plan to do:

    For the front - clip on's, smaller headlight, smaller indicators, smaller gauges, new metal panel for the warning lights.

    Either paint the stock tank or get another tank.

    Use the old seat base to get a new seat made up (brown leather).

    Try and find some wire wheels, and put Firestone tyres on.

    Get pod filters fitted and the carbies re-jetted to suit.

    (Maybe) polish the engine.
  12. I missed the point of the RWC? Is it to transfer rego? Is it to re-register a lapsed rego? In either case, I'd *strongly* suggest you get the RWC out of the way before you start tinkering. It looks like you're nearly there anyway? Get it running, and take it in. You could be opening a can of worms if you try and do it later.

    You're gonna have to figure why it's not running sooner or later, so do it now, get it passed, then hack away at it.

    Sorry, but you did ask :wink:
  13. You would say that, you Honda Hater you!

    I quite like the Comstar wheels, I reckon you should keep them & paint them white.
  14. Pervert :wink:.
  15. If you're going to pods then be prepared to upjet somewhere in the neighborhood of 15 to 20% on your mainjets (ie #100's become #115~120's), then raise the needles anywhere between 1 and 3 notches, and downsize your airjet by maybe one size. If its a pilot instead then try one size larger.

    Pods'll look cool, but make sure you tune them well or you could destroy your bike.

    Good to see you're giving here the go-over, anyway!

    Cheers - boingk
  16. Progress (sort of)...

    Met with Christian at Modern Motor Cycle Company yesterday and planned the mods to the bike that he can do, including clip on's, new smaller headlight, new blinkers, remounted warning lights, wrapped exhaust, new reverse cone muffler, new air pods and jets and carbie tuning, reupholstered and restyled seat and general clean up for RWC.

    I bought the bike unregistered as a project bike, so getting a RWC will be part of the project, this will be managed as part of the rebuild, in other words - keeping blinkers 300mm apart, keeping rear pegs on for the RWC, etc...

    Due to budget, I will be keeping the five spoke wheels for now, but probably painting them black or white (not sure yet). The tanks will be white (antique white) with a brown stripe and the headlamp bowl will be white, so maybe white wheels will work too. Need to talk to my good mate Mitch about the paint jobs.

    As for the space under the seat, for now I will keep the battery and oil tank there, and I am going to fit 'saddle bags' that sit over the space where theside panels were. The saddle bags should work the same way they work on a horse, flip up the seat, lay the saddle bags across the bike frame so they drape down each side, close theseat over the top and that will hold them in place.

    Here is the left hand saddle bag finished and taped in place to see how it looks.

  17. Oh dear.
  18. It's okay - I think I will stick to my original plan of 'paint the wheels black so I can pretend they are not there' whilst I continue my epic search for wire spoke wheels to suit (hopefully with twin brake discs on the front wheel).

    Todays good news is that I stripped the front down (who is the sadist who designed the wiring loom inside the headlamp bowl? Every wire has to be unclipped to remove the loom as it passes in one hole and out another!).

    After removing the horns, headlamp, handlebars and top triple - I slid the front indicator and headlamp mount sleeve off each fork and...

    ... perfect shiny rust free forks. Great news for the front end. Clip on's here we come.

    Took the headers off, they have been patch welded at the 4 into 1 joint in the past but otherwise they are okay - cloth wrap will hide a multitude of sins.

    Stripped the seat pan back, the metal base was rusty along one edge but I had a crack at repairing it. Not sure if I will use this base for a modded seat of my own design, or just lash out and buy a NitroHead seat.

    Mistake of the day - levering an obsolete frame mount off the oil tank and finding out it was riveted on, I now have three small holes in the oil tank to fix!