Honda CB750K5 Restoration by Royhall

[Johnny4428]

I used the two socket method but in the vice instead of the threaded rod on the 550, problem with the vice method you need three or four hands to set up. Good tip on the grease on threads to maximise pressure. On the 750 I used the hacksaw method very simple and no pressure required to remove.

[Laverdaroo]

I've just done the two ancient ones on the 550 swinger, prepping it before it went to blasting. After drilling them around the rubber with a drill bit and a quick slice with the hacksaw, they tapped out really easily this time ........compaired to the 400 which might as well hve been welded in there

[royhall]

It's been a while since this thread was updated, I have spent so long ontut tinternet looking for bits I just haven't had time. I sent the powder coating out to the guy that did my last 3 frames along with all the bits and pieces (as per previous photo's) and he turned it round in a week for £170. So really pleased with that, especially as he initially said he wouldn't do them due to selling the business that has since fallen through (good for me, bad for him). Not got many pictures as I have bubble wrapped everything into a storage box for safe keeping before I remebered to photo them. I really like the fact that they think about what they are doing with things like masking off, and keeping it thinner around the frame number so that it remains visible.

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The carbs that arrived with the bike were in a bit of a state. They were seized solid and looked like they had been dropped. They also looked like someone had tried to get them apart. Anyway, James sold me a decent set so I could make up one good set from the two. I sent these to Gerben in Holland (read other post about messing up the import duty thing to the tune of £91). They are at the moment on route back from Holland but Gerben has sent some pictures, fantastic job. Before and afters:

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Will do more updates when I have time.

[taysidedragon]

Those carbs are beautiful,  a work of art!

[royhall]

Knowing Gerbens work, they will be as good inside as out and work well.

[Johnny4428]

I agree, they look the part.

[McCabe-Thiele (Ted)]

Those carbs look fantastic - I like the fact you can see the frame number as well - my powder coater asked me if I wanted to have the frame number masked off - I said yes but he forgot so you can't see it anymore you have to rely on the plate. grrrr

[Laverdaroo]

lovely set of carbatooters they look fantastic

[royhall]

After James's triumph with the police bike in what appears to be such a short time, this 750 is crawling along at a snails pace. I really don't know how James has the time and energy to achieve what he does, probably doubles his day by not sleeping. 

Anyway, as you know from previous posts this one came with chain break damage to the crankcases and I bought a seized spare engine off James for the cases. That meant I had two engines to take apart and the spare engine was a royal pain in the arse to strip. I think it has been sat in a damp atmosphere for a very very long time. As it turned out, it was a good buy as it's given me the parts I required to replace the damaged parts in mine.

The chain break had been filled with clear silicone which had layers of old black chain lube and crap over it. I assume from the grease that the PO carried on using the bike after the cases got smashed. The gears have milled the insides of the cases and oily swarf is filling the bottom case, there was way more in the sump pan.

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The spare engine finally came apart after lots of PlusGas and heat, I was careful to make sure that if there was damage it wasn't to the crankcases. The only issue was one broken 6mm bolt at the front of the case that was rusted so tight I had to drill it out. I was expecting to have to use an insert to repair it but managed to drill it bang on centre and clean out the thread (that's probably a first for me). It is very slightly loose but I think it will be okay.

Although the original engine turned okay, there appears to be some damage to the crank. The damage actually feels very smooth so I'm wondering if it was caused by soft aluminium swarf or it's a surface problem on the crank itself. Possibly some white metal from the shell due to not being turned for years, I may try to polish it off. Anyway, the crank from the spare engine is in good condition although the alternator rotor was as good as welded onto its taper. It took heat, easing oil, and a sacrificial bolt and heavy hammer to get it off. Bloody thing has ruined my removal tool. At one point I had the removal tool, heat, oil, and a three legged puller on it and it still didn't budge. At least it's off now with no damage done. Long ago someone took the cover off the left side and it had all gone very rusty.

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Both the engines are now apart and the cases are nearly ready for vapour blasting. At some point I will have to go though all the parts and pick the best of the two for the engine rebuild. The parts that made it to the scrap pile were the top and bottom damaged crankcases, the cylinder block-pistons-conrods from the spare seized engine (again they are welded in there) the cylinder head from the spare engine (broken fins and two broken spark plugs plus all valve seized that tight they cant be hammered out). Shame about the scrap bits as I was hoping to sell the bits on to offset the cost of the spare engine. If it was a Brough Superior I would have salvaged the parts, but they were far too damaged to be worth it on a Honda. Anybody wants them there yours for the price of the postage. I am keeping the damaged top case until it's registered with DVLA as it is proof of the original engine number.

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There are lots of other bits done that I haven't covered yet. I really must try to keep up with the build thread, but it's a choice between being in the garage doing the bike or sitting at a desk typing. A clear winner there. Plus I keep doing things and forgetting to take photo's. Must try harder.

[royhall]

The postman has just called with my V5C from DVLA. Not too shabby, it's taken 2 weeks and 5 days including post time. Thanks to James for the V55/5 form that he pre-annotated with all the correct details. If anyone wants a copy of that just ask. I have checked all the numbers on the V5C and everything is correct first time out, including the change of engine number. She is now LFM 992N, and I have even remembered to declare it SORN as it's not insured yet.

Edit: I don't need to keep the upper crankcase for it's number now the V5C has arrived.

[Laverda Dave]

Good progress Roy. That was some painful damage caused by the chain break.

[JamesH]

Great progress Roy. Don’t be disheartened - I never underestimate the amount of time taken to properly strip and rebuild these engines. I’m a massive cheat in that respect and outsource my engine builds to someone with way more skill than me. I’d say 1/3-1/2 of the time taken on a proper restoration is taken up dealing with the engine - so you’re putting me to shame there

Keep the photos and progress updates coming - great news on the speed of the DVLA turnaround


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[baggins]

The postman has just called with my V5C from DVLA. Not too shabby, it's taken 2 weeks and 5 days including post time. Thanks to James for the V55/5 form that he pre-annotated with all the correct details. If anyone wants a copy of that just ask. I have checked all the numbers on the V5C and everything is correct first time out, including the change of engine number. She is now LFM 992N, and I have even remembered to declare it SORN as it's not insured yet.

I did a double take when I saw your reg number. I had my docs back at the start of the week for my american import K5, took a bit longer than yours mind, but I have the registration  986N. Small world eh!

[Laverdaroo]

Never realised there was so much copper pipe in a 750 K5 lump


Stick with it, mines in a billion bits but once the cases come back you'll be flying. Not an easy one to take on and I take my hat off to you for attempoting it. Its really coming on, stick with it and befor eyou know it you'll be on the good but which is putting new bits together and matching them with the old stuff....................my favourite bit, at least you can see where you're going and more importantly where youve been.
Like you, Im guilty of not taking enough piccies but I will, like you, try a bit harder


Keep at it Roy

[Laverdaroo]

At least your rotor doesn’t look like this!
I think something was loose and managed to be dragged around the case. Hard to believe but how else would this happen?


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