Honda-SOHC

The blue goes well with the mud that is about to cover it! 🙄. It does look very tasty.
Temperature is going to reach 17deg by Friday. Spring is chasing winter away (hopefully 👍).

I found if using clamps they are too big and foul on the upper crankcase. I've always fitted them without clamps, the taper is normally enough although I compress the rings using two coffee stirrers as the piston ring enters the taper of the individual bores. Use plenty of oil on the bore at the taper end and plenty on the piston and rings. Go very gently and have patience, just tap the cylinder block down over the pistons with a gentle tap using the palm of your hand.
I've never broken a ring using the above method.

I'll be going Steve. Visiting the classic car show first though as have a free ticket 😊. What time are you going?

Thanks Julie. My fingers and toes are crossed this time!
I cannot belive how much quieter the engine is though following the latest rebore, its a different bike!
I'm sitting on a train on my way to Westenhanger now to collect the fairing. I think I'll be sending it to Menno for a respray to match the tank etc he painted last year. Just wish I could find the engine bar.

It's going to be a good read Roy so I'mooking forward to it.

Well, after a lot of faff the bike now runs and is much, much quieter than before!
In the end I bought a s/h barrel from ebay for £10 rather than throw a £100 genuine Honda ±50 piston and rings into the bin. I had the barrel vapour blasted as the paint was in a bit of a state and repainted it using PJI satin black (although once cured in the oven it is more matt than satin). I had the barrel bored to the middle tolerance as specified in the Haynes (and Honda) manual. The engineer cried 'no, it will sieze' but after explaining the Honda metallurgy methodology he relented and did what I asked. He warned me when he has bored previous CB250RSA engines to these clearances they have siezed as they run very hot. He also said the ones he worked on previously were dispatch bikes with pattern pistons so I guess they might well have siezed if subjected to london's cut and thrust traffic from the word go!
Im not counting my chickens yet given my previous two experiences but I ran it for 42 miles, it was amazingly quiet (the previous oversize rebore must have introduced piston slap of another level!). The best thing, it used no oil whatsoever, previously even after 42 miles the oil level would have dropped slightly!
The only slight downside is I noticed a slight weep coming from the end of one rocker shaft, oil weeps from these are a common problem on these engines. It wasn't there before so I'm at a loss why its strarted now? I know I'm not taking the rocker cover off again to remove the rocker shafts and replace the o rings. What should be an easy job isn't on these engines due to the stupid pressed in dowls being impossible to remove without a spark eroder!
If anyone has any suggestions for an alternative potential cure I'm all ears 👂😊.
Thanks for all your previous advice, hopefully it will run as it should from now on 🤞!
Tomorrow I'm also collecting the CB250RSA holy grail.... A genuine 'Hondastyle' nose fairing, as rare as hens teeth to find in undamaged condition.
If anyone has a set of front engine bars they wish to sell please let me know.

Looking good👍. More pics please so we can see it in all its glory.

It's 1970's alloy finned period tat introduced prior to the invention of 1990's anodized period tat. Apparently and despite advertising claims to the contrary, adding period tat does not make a motorcycle go any faster.....