It has arrived!

[JustcallmeMrT]

Apologies, I just looked again and its the small bolt hole you have fractured, probably be fine with alloy welding, for some reason I had it in my head it was the big un that had cracked, probably because on mine it was the big bolt lug. I am bound to still have the forks in question and if needed can dig them out and sell you the spare lower leg provinding it passes muster, ie no stripped threads etc. One word of warning though, with so many project machines I am inclined to take an age to find bits or even forget why I went out to the shed and get distracted by rusty things so may need reminding.

You guys are amazing with all the help and offers.  I'll keep you posted as the build progesses - I'm holding fire on new parts until I know how much the engine is going to cost me. 

[Trigger]

Engines can be a open cheque book. Just do not get carried away with the finish. Polishing and new chrome can cost more than the engine parts.

[JustcallmeMrT]

Does anyone know the thread size for the brake bleeders?  Looking to buy speed bleeders and they've got multiple sizes....

[Trigger]

7mm. You do not need a speed bleeding kit. I never have any problems with these brakes. People for get that it is a system and must be treated as one.

[bike-pusher]

I'd ditch the Comstars too.

I remember twinning the discs on my old SOHC CB750, back in the day.  You need longer bolts to pass through both discs - Gold Wing GL1000 units fit.  And then there's the speedo drive - the CB550 tin cover was necessary on the the 750.

The master cylinder will not flow enough fluid. Trust me on this.

You might like to know that the CB550 shares the back wheel with the CB500T.  However, for some extraordinary reason there are two different types of brake plate, and you need the spacers as well.  I shoved a CB500T rear wheel into my last CB550 because the original had cracked.

And that's a real one to watch for - the cast iron liner is very thin and can crack if it gets corroded.  Then you have an oval rear drum.  I imagine a good engineering workshop would be able to put in a new cast iron liner and machine it to fit, but it's easier to replace the whole wheel.

[matthewmosse]

 Brake rear liner is a perfectly do able job, if you have a lathe and patience, I have done them for myself but there is a guy who does thrm professionally at a price I wouldn't hesitate to pay. The different back plates issue is one to watch out for across any of the cb500 and 550 bikes, the change seems to have been arbitary, and owners may have mixed and matched since. I had comstars on one of my 550k3s and thought they looked pretty neat, I got away with stock master as far as I know though all the advise is to upgrade, maybe I had a upgraded one? I called that bike 'box of cogs' as that was the condition I bought it in, £200 for a van load of cb bits, mostly cb250N but a complete 550, with several engines but every engine was in bits. If you ever wondered what a mess a canchain can make, think along the lines of only being able to use the selector dog shafts and cluch plus cover out of a whole engine. I think the pistons would have been ok if the damp hadn't got to them and sized the rings in solid. 
Regardds bleeding the brakes, my preffered method is a bit of clear pipe, comes with most bike batteries for free and a big seringe to squirt fluid up to the master cylinder from below, I had several that would not bleed the conventional way , this way got it moving, then I suck the fluid back down from the master with the seringe until it runs clean and free of air bubbles.

[tom400f]

Regardds bleeding the brakes, my preffered method is a bit of clear pipe, comes with most bike batteries for free and a big seringe to squirt fluid up to the master cylinder from below, I had several that would not bleed the conventional way , this way got it moving, then I suck the fluid back down from the master with the seringe until it runs clean and free of air bubbles.

Exactly this. How I did it and takes no time. Firm hydraulic action thereafter.

[JustcallmeMrT]

Thanks again for all the tips guys, as I said before, I'm totally new at this so all advice is welcome. 
The original bleed valves seem pretty corroded, so I figured if I had to replace that I'd go the speed bleeder route as I'd read a number of posts where they were recommended.  But, if originals work fine with the methods you give then I'll stay original.

The comstar wheels are going to go.  I have the original spoked wheels and like the look much better.

[Bryanj]

Before trying to undo the bleeders heat the caliper with a plumbers blowtorch and spay on wd40 or similar (don't stand too close due to lots of smoke and maybe small flames Also use a Tee bar on a deep socket to get an even "Turn"

[bike-pusher]

What he said.  I always heat up the caliper before trying to undo those tiny Honda bleed nipples.

[JustcallmeMrT]

Ok, next set of questions has to do with the carbs.  The PO mentioned that when he swapped the engine, he also put on 'new carbs', but didn't know if they were same as originals or not.  So, how do I ide tidy which carbs I've got?  Pictures below.

[SteveD CB500K0]

Easy.
You have 069A carbs!

[JustcallmeMrT]

Ahhhh!   Can you tell I'm new? 

[SteveD CB500K0]

I'd love to expand, but as a 500 guy, I only know about 627s.

We do talk a strange language don't we?

[Trigger]

Where is the bowls from the carbs???