1975 CB750k2 cafe build

[benholmes21]

Hi

Thought I’d finally get round to making a thread on here for my CB750 build after being on here a while looking at everyone else’s build.

I bought the bike in January, looking like this and although fairly original, it had been sat a long time after a partial restoration and under closer inspection, it wasn’t quite as immaculate as it appears on the photos!




Within a week the bike was stripped fully whilst I worked out which way I was going to go as I really like the mix of cafe/brat bikes.

The rear of the frame was cut and an upswept hoop added, ready for moulding a fibreglass hump and aluminium seat pan.

The tank was blasted at work, which I found had a good few dents in, hidden by filler so plenty of new parts have been ordered from 4into1  which I shall update with as I am currently waiting on that much I’ve lost track of what’s actually been ordered. I treated it to a replacement exhaust as the black one was a bit rough and didn’t quite fit with the look I wanted so opted for a Delkevic stainless system and a new throttle assembly for minimal hand controls too.

I also shaved the top yoke/clamp as I wanted a minimal cockpit but this has now been sold as I’ve replaced it with a billet one from Cognito Moto







When welding the hoop, I turned two plugs and plug welded them into the hoop and frame then seam welded them.

I didn’t want to leave an open gusset so shortened the original sheet metal shock gusset and welded them back on, so they just need the welds fettling to smooth them out.






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[UK Pete]

Looking good

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[benholmes21]

Thanks!

I’m currently waiting on a 3 big shipments from across the pond from Cognito Moto, 4into1 And CycleX so hopefully once these show up, there will be a little more interesting photos!


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[Bryanj]

Welcome after the trip from the US forum, On there you asked about 500 swing arms if you really want to go that route I may have a spare but you still have the problem of the wheel as I doubt a 750 will fit and I am sure the swing arm is narrower so big tyres rub

[benholmes21]

Welcome after the trip from the US forum, On there you asked about 500 swing arms if you really want to go that route I may have a spare but you still have the problem of the wheel as I doubt a 750 will fit and I am sure the swing arm is narrower so big tyres rub

Thanks Bryan!! I did indeed, I had read somewhere that it was a direct fit on the CB550 to the 750 and I could use the 750 rear wheel.
Seemed to be most people swap because it’s slightly longer and allows more clearance on the rear wheel? Although I could be wrong!


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[benholmes21]

This evening I managed to beat the bush... so to speak. Removed the rear shock bushes and also swingarm bushes. I had already shaved the chain guard mounts off, so now the swingarm is ready to go to powder coat and waiting new phosphor bronze ones from TwoWheelFrank.





Also, here’s the stem I’ve just finished. I have a billet top yoke from Cognito Moto waiting to go on. I’ve removed the switch block and polished it to match as I’m using a new master cylinder/lever with an integrated switch.





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[benholmes21]

So... after planning on rebuilding the original forks with new fork tubes, seals, top caps etc which I have in the garage.... plans have slightly changed after today these have been delivered



So a quick call to CognitoMoto before my order was dispatched to add a few little extras into it and just a waiting game until that comes with lots of goodies that’ll bring the build on hopefully!


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[Rob62]

Very interesting... looking forward to seeing this one completed. When you say “ here’s the stem....” have you made a new one and re-fitted it ? I have a spare bottom yoke with a bent stem which i would like refurbishing i.e. new stam turning and welding up, if you know anybody who can do this.

[benholmes21]

Very interesting... looking forward to seeing this one completed. When you say “ here’s the stem....” have you made a new one and re-fitted it ? I have a spare bottom yoke with a bent stem which i would like refurbishing i.e. new stam turning and welding up, if you know anybody who can do this.

Thanks Rob! Been a little slow with updates but I’ve cut and welded a delkevic exhaust to make a “shorty” so to speak, and I’ve been working with the father in law (to be) on a rear cafe hump as he’s been building and making model aircraft that he flies since he was a boy so has a much better eye for symmetry and detail than me.

Just waiting to get the engine blasted and it’ll be ready for paint!

Apologies, by stem I meant lower yoke and stem, which I’ve kept the original stem in it. I’m sure most machine shops could turn you one up. I have a lathe at work but it’s the metric fine due to cut the threads I’d struggle getting.

Cheers, Ben


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[Rob62]

Ah I see.. I wish I had access to a machine shop, i used to be a turner many moons ago, i could make my own... BTW You need a 127 tooth change-gear to cut metric threads on an imperial machine iirc.

[benholmes21]

Ah I see.. I wish I had access to a machine shop, i used to be a turner many moons ago, i could make my own... BTW You need a 127 tooth change-gear to cut metric threads on an imperial machine iirc.

That’s the joys of being machine tool maintenance. Not much I can’t get hold of at work really. Although when it comes to gearing etc, that’s where I’m useless as Im not a machinist, I just can turn/mill etc


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[benholmes21]

So not much has been happening recently as I’m still waiting for a delivery from the USA with the parts I’ve ordered.

But hopefully next week the engine will be being stripped and painted in some VHT Nu-Cast aluminium. I have also painted a few casings with VHT crackle grey too....



I finally managed to get my hands on the correct CB550 swing arm to replace the standard one so I can run a wider rear wheel/tyre, and also being tubular it looks more in-keeping.

You’ll see that the undertray is finally welded in too so the frame/swingarm isn’t too far off going to powdercoat!



The delkevic exhaust I bought was originally up for sale, but I decided I’d chop up a brand new exhaust and make it custom, so I’ve just got to weld a new mount onto the frame once the engine is back in and it’s mocked up.



The father-in-law, who’s garage has been loaned to me after selling my house, has helped make and shape the rear hump that will hide the battery and electrics, so we just need to fibreglass it and that’ll go to paint with the tank and headlight soon.






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[SumpMagnet]

Looking interesting

Love the colour this thing started out with. Nice shade of blue!

What are you using to shape the polystyrene with? I am planning a mild cafe racer look for mine and fancied having a go at making a seat. I have done plenty of fibreglass work before, and have always avoided using polystyurene as a mould as cutting it was messy and bothersome. Yours looks really neatly shaped.

[benholmes21]

Looking interesting

Love the colour this thing started out with. Nice shade of blue!

What are you using to shape the polystyrene with? I am planning a mild cafe racer look for mine and fancied having a go at making a seat. I have done plenty of fibreglass work before, and have always avoided using polystyurene as a mould as cutting it was messy and bothersome. Yours looks really neatly shaped.

Thanks! Yeah it is quite nice but I think I’m aiming for more of a paste blue or a pastel green, although not full decided.

My father in law made the hump. We used a hand saw to cut the block to shape and then made formers. He used a hot wire to perfect the shape then finished it off with a little sanding. Hopefully it’ll be fibreglassed this week!


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[benholmes21]

Quick update as a lot has happened over the last few months...

Moved house, so the Honda went back into boxes until it was unpacked into the new garage...

Here’s a few photos to update.




Carbs turn up from the states, got them from CycleX and they’re ready spaced for the CB750! Along with lots of other goodies that hopefully you’ll see soon.



Engine all painted, starter motor now rebuilt and installed too.




In the last stages of mocking up and the frame, etc should all be going to the powdercoaters in the next few weeks... ready to start the rebuilt

Cheers, Ben


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