1975 UK CB750k2 cafe build

B

BenHolmes21

Guest
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 18 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!
 

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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
 

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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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rohalloran said:
Good start. Rebuilding one myself so looking forward to following your build.

Thanks!! I’ll keep my eyes out for yours on here too! When I bought mine, I said... it’ll just be a quick project and more something to tinker with and it’s slowly spiralled deeper into a full strip down!


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BenHolmes21 said:
Thanks!! I’ll keep my eyes out for yours on here too! When I bought mine, I said... it’ll just be a quick project and more something to tinker with and it’s slowly spiralled deeper into a full strip down!

All Mine end up like that :)
 
It's structurally advantageous to have an open gusset, less chance of cracking. That said, I can't see that area taking such stresses so looks are probably a worthy priority.

It's just my opinion, for course, but brat style set ups never look quite right on big bikes. Some derivative of a cafe style arse end would look much nicer.
 
The decision was purely aesthetic not to leave the gusset open, although I knew keeping a rad on the gusset would improve the strength and less chance of cracks propagating on a radius, but thanks for the heads up

I totally agree with you on the rear hoop but the plan is to even out the look by shaping a rear cafe hump to hide the battery in eventually.

Currently making an undertray to weld in with the seat rails and then I can focus on getting messy with the fibreglass hump.


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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.

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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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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

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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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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....

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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!

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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.

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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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Have you thought about mounting battery under swing arm along with reg /rec .makes wiring easier?
 
Sderbyshire said:
Nice work , it’s going to look fantastic !

Steve
Thanks Steve... just trying to decide on the colour Togo with at the minute... whether to stick with the original blue or change it up a little.

yozzer74 said:
Have you thought about mounting battery under swing arm along with reg /rec .makes wiring easier?

I did think about it, but because I’m using an M-unit, I’ll be making a new wiring loom anyway, so having the battery under the swing arm will make it harder for me to hide the cables really. The reg/rec is going on the underside of the tray I’ve welded in.


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I used m unit ran wiring through frame bit more work but really clean look .just a thought .are you going for open look in middle of bike ??
 
Also looking at your tray have you checked the travel clearance of wheel to tray with suspension travel ?? When I did mine I spoke with hagon .they say you need 90mm minimum. Just trying to help mate .
 
This was my 750 I did.I didnt use m unit on that build had battery under seat like your doing .
 
yozzer74 said:
This was my 750 I did.I didnt use m unit on that build had battery under seat like your doing .


Thanks for the idea! I think I’ll stick to the battery under the hump rather than on the swing arm, as it’ll save running lengths of wire through the frame.
There will be clearance on the frame too, I made sure that I went for the upswept hoop too as it sits higher than the original frame rails.

Your bike looks cool! I like that!
I’m going for a lithium-ion battery so I can keep a really small, sleek hump behind the seat.

Also, for the oil tank, I have one of the CognitoMoto oil tanks on its way, so it’ll keep the triangle fairly open.


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Cool looking forward to seeing how it turns out .here's a build thread that might help you .don't know if you have seen it .http://www.dotheton.com/forum/index.php?topic=63693.msg726426#msg726426
 
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