Honda CB750K5 Restoration by Royhall

[royhall]

Yes Ted it's polish. Also what looks like a scratch on the last photo was just something stuck to the bottom of the tank which is now gone.

[McCabe-Thiele (Ted)]

I bet that was a relief - I'm scared of chipping my tank when its done whilst fitting it to the frame - one of many things that keep me awake at night. lol

[K2-K6]

Looks really good Roy.

I think the red colour is more popular, well it seems that way in general conversation here, but I've always preferred them in blue and a very nice job they've done there too.

I'd be happy with that 

[Oddjob]

Nice job there Roy, is he available for other work or was that job just a friend helping out type of thing?

Like the colour.

[Matt_Harrington]

What a fabulour colous - noted for future use!! 

[philward]

Lovely paint Roy - at a really good price too

Sent from my moto g(50) using Tapatalk

[royhall]

Morning. It's been a while since the last update although the project has moved on quite well. Will have to try and get the thread up to date if possible. In the main I have been trying to fit electrical components so that I can make a start on the wiring. I hit an unusual snag at the first hurdle. Having successfully fitted the rear light and rear mudguard it was on to the indicators. The K5 has the larger indicators with the thicker stems, they fit to the grab rail with rubber isolated mounts and a riveted on earth wire. It appears that I have K5 indicators and a K1 grab rail and the two are not compatible. So with a good bit of measuring and a hacksaw I modified the mounts to fit, this required cutting off the rivetted earth lead. Once I had them fitted okay I touched up the black paint and connected a new earth lead directly to the indicator (to be fair I always do that anyway).

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Having got over that little glitch I treated myself to an easy job fitting the front calliper and brake hoses. The original was way beyond re-use, in fact it was way beyond anything I have encountered before. So an new one was ordered from DSS along with new original pipes from somewhere else (can't remember where I got them now). Fortunately these just bolted straight on without any hassles, nice to get a job that moves the project on without frustration. For now I am not going to fill and bleed the system just in case something has to come off again, I will do that job just before it hits the road.

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At this moment the bike is still sitting on the beer crate so hopefully the next job will be to get the centre stand fitted and get it on it's own feet.

[Johnny4428]

Nice work there Roy! That’s a clean looking brake disc is that new?

[royhall]

Whilst getting the bikes main stand fitted, which went well without any glitches, I decided now is the time to do the job that I have been putting off. Earlier in the build a few problems became clear, the swing arm bushes were binding on the frame causing stiction in the suspension and I had also forgotten to fit the earth strap between the engine and the frame. The earth strap had an additional problem in that due to forgetting it I didn't remove the powder coat or engine paint to ensure connection.

I really hate having to go backwards but it's more important that the job is done right. So to gain access I removed the rear wheel and the swingarm, along with the battery box. This gave just enough access to deal with the earth strap. The plan is to use the angle grinder fitted with a very thin cutting disk (for stainless steel) to remove the paint without having to take the engine out again. It worked absolutely spot on with the earth strap just requiring tapping into the gap and the engine bolt replacing. For all you Health and Safety fanatics, yes I know the guard is missing from the grinder, I had to remove it to get enough access (don't play this at home children).

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On checking the swingarm bushes they appeared to be fitting okay in the swingarm so I had a close look at the frame. I usually remove the powder coating before fitting the arm but in this case that hadn't happened (my bad). On checking, the powder coat had a lump in it that turned out to be weld spatter powder coated over. As no welding was done on the frame, that must have been there causing a problem for nearly 50 years. I ground off the coating with an emery wheel back to flat metal and re-fitted the swingarm. This time it was buttery smooth. Result.

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Having reassembled everything I set about fitting the non standard regulator/rectifier to the battery box. I actually cut off the mounting on the battery box for the standard rectifier to make room for the combined unit (after first checking eBay to see if replacements were available). As the hole centres were different I made an aluminium mounting plate, and as you can see from the pictures it worked nicely.

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The next item on the agenda will be fitting the non standard Boyer Bransden micro coils.

[royhall]

Nice work there Roy! That’s a clean looking brake disc is that new?

No it's a standard part that's been painted on it's centre and re-ground slightly to remove the minor scoring. To be honest it's better than a new part.

[Johnny4428]

Nice work there Roy! That’s a clean looking brake disc is that new?

No it's a standard part that's been painted on it's centre and re-ground slightly to remove the minor scoring. To be honest it's better than a new part.

Nice to get it skimmed, thought it looked good. Had the 550 one done but my 750 one was ok.

[royhall]

Whilst I'm in bracket making mode I will have a go at the Boyer Bransden ignition system. I was going to use a simpler device that just does away with the points then remembered I already had this sitting on the shelf as it was originally fitted to my CB350F. The first problem with Boyer is fitting the coils and box, they say to fix the box to the frame with cable ties. Trust me on this, that won't be happening. For the coils I modified the brackets I had already made for the 350 so that wasn't a major issue.

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For the blue box control unit I decided to fit it behind the side panel with the rest of the electrics. As I have already fitted the reg/rec unit in there, available space is low. The blue box has no means of fastening so I utilised the mounting point for the original regulator. I made a flat aluminium plate that bolted firmly to the mount, then stuck the box to it with double sided Mammoth tape. You could stick you granny to the ceiling with that stuff. Worked out quite well but I was a bit concerned about heat from the reg/rec unit, but as Boyer say to mount it right on top of the engine I doubt that it's a concern. As a bonus, it's now close enough to connect the blue and yellow wires from the pickups without going through the harness, I will just need to extend two wires to reach the coils.

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Just a few more items to be fitted and I can start the wiring. Not really lookind forwards to that.

[Laverda Dave]

All looking good Roy. Very nice fabrication work going on especially with the coil mounts, they look OEM.

[royhall]

I have been dealing with the electrics on the bike and it has been quite frustrating. I wont repeat everything again here as I addressed it on another thread. Just for completeness on the project thread it is on this link.   CB750 Wiring Issues (sohc.co.uk)

[McCabe-Thiele (Ted)]

We've all had Groundhog Days Roy - I had three on my 400 build.

I've been reading your electrical thread - very frustrating things vehicle electrics  - you start off at one end a battery with just two connections then the spaghetti trail begins.