Honda-SOHC

If your brass bits are OEM Keihin, thoroughly clean all the brassware, jets, emulsion tubes etc by removing them, then re use. Fit all new Viton O rings (I stock the kits), re use the top gasket.
Carb cleaner is good but make sure you get it in all the hidden passages. Ideally, an ultrasonic cleaner is best (after removing all the internals) then you can get the entire carb body thoroughly clean. But, if all you have is carb cleaner, use that.

Thanks everyone for your replies. Nurse Julie, when you say do exactly as it says on the tin, do you mean including heating to 220 degrees c? As Oddjob mentioned, I've seen on the internet that aluminium can distort at relatively low temperatures, but then I am aware you can't believe everything you read on the net.

Alloy sheet may distort at 150° but alloy engine cases don't.
The only time we prepare to prevent distortion, is on bottom engine cases that need major TIG welding for major chain  damage repairs on Sandcasts/ K0's, which is 660°. We bolt the case to a jig to prevent distortion during welding.
As far as the painting is concerned, the most important thing is to make sure all old paint/ oil etc is removed prior to painting. The parts must be thoroughly clean, we had all our engine chemically dipped to ensure no contaminates were left on or in the metal. If there is any left, it will just leach out under the new paint. Wipe parts down with clutch and brake cleaner.
So......
1. Prep the cases fully.
2. Heat cases in oven to 50°c.
3. Heat can of paint in hot water.
4. Spray 1 mist coat.
5. Leave for 10 mins and spray another light coat.
6. Repeat No.5.
7. Air cure somewhere warm and dry for up to 24 hours.
8. Put oven on at 50° and and gradually increase in 50° increments over 1½ to a maximum of 220°c.
9. Turn oven off, leave parts in oven to cool until cool enough to handle.
10. Remove parts from oven and air cure for 24 hours somewhere warm and dry.
Doing it this way, we have never had any distortion ( the parts are only at 220° for about 10 minutes), nor have we had any discolouration.
As far as fuel damage is concerned, paints like this are 'fuel resistant'. If painted and cured correctly, wipe any fuel spillage off, ie at the petrol pump, as soon as you can and it will cause no damage. Leave the fuel on without wiping it off, it would cause some damage. The easiest thing to do is not have leaky carbs or tap, then you won't have a problem.

Cillit Bang limescale remover cleans the brass bullets and spades up really well. Then do what Bryan says.

Very nice John. I love any bike that upsets Greta Thunberg 🤣🤣🤣🤣.

Also, only get the rebore done by someone who understands Hondas tight tolerances. We've retired now but Bryan may be able to do it for you.

You need to measure the bores to work out if they are still within spec to use those pistons with new rings. Personally, I would not use those old pistons anyway, I would have a rebore and fit a new oversized piston / ring kit. If you try and cut corners or do things on the cheap, these old engines have a habit of coming back and kicking you in the backside.

It's still a lot of money for a bike that can never be ridden. Without premium, that's only 40k less than the Brighton Bike which is a rider.
Edit..... 40k more, not less 🙄🙄🙄