The motor was as mentioned before, covered in grime, oil and about 20 odd years of caked on whatever as it sat unloved.
As cleaning grote by hand is tedious and MESSY, needless to say I didn't take pictures during that phase. You can refer back to the beginning scribblings to get an idea what it looked like when I first started this.
The actual cleaning is messy and time consuming but to make it easier on myself I used a toothbrush (an old one my dear), some wire wool and Autosol, carb cleaner or WD40 in combination. The results were pretty good, even in the hard to get to places such as between the fins on the cylinder barrel on on the head itself.
Judging by the amount that I saw and had to deal with, there might be a leak somewhere between the cylinder and the head. But I decided against an engine strip down as I wanted to see if the wee beastie would run and also to see, after it was all cleaned up and running, if I could detect the source.
It was amazing the places all this gunge could get to; all over the back of the engine, the rear mudguard, the swingarm pivot, the rear hub, the frame rails, and the oil tank.
It all eventually was cleaned up and parts that needed replacing got replaced. A couple things that were replaced were the drive chain which was covered in rust and I suspect the rust had gotten down into the rollers and pins, the overflow pipe from the oil tank was missing so a length of clear tubing was cut to size and added.
I at this time also installed a chainguard as well. The original had gone walkabout years ago for some reason and I discovered that chainguards for B25 Starfires were as rare a frog lips, even on eBay. So I improvised by installing one off a BSA B50 in it's place. The mounting brackets had to be re-positioned a little and some fasteners from my oddment tin were used, but in the end it worked out OK and really doesn't look out of place.
To finish off the engine work, the carb was cleaned up, a brand new silencer was ordered from Lightnening Spares in Sale, Cheshire along with all the rubber bits for the footrests and the gear lever and kick starter.
Here's a picture of it still on the bench just to show what it looks like at present:
And no, I know what you're thinking, the pan of oil underneath isn't coz it's leaking oil. It's after I drained the crankcase and any run-off from using cleaning fluids.