Paz2112 wrote:Need some guidance, the master cylinder seems to be leaking now that i have started to use it. NLM offer either a 16mm or 19mm seal kit, question is (probably dumb) what does this apply to, is it the diameter of the piston?
It's the piston diameter.
Stock setup for a 350 with single front disc is a 16mm cylinder, which many find gives a rather 'wooden' feel. A 19mm cylinder is stock for a (factory) twin disc setup and likewise gives a rather wooden feel. The 250 uses the same front wheel disc and calliper, but a 14mm cylinder, which feels much better. Some owners have gone smaller still, 12.7mm (1/2") being quite popular and I think some have gone down to 11mm for a modern two-finger lever. Personally I like a heavier/firm lever and find that the 16mm cylinder paired with twin discs is perfect.
Complete new mastercylinders are quite affordable and are pretty much guaranteed to work. I'd strip your cylinder before ordering seals and make sure it's in good enough condition to rebuild first. Make sure any seal kit includes the dust bellows too if yours isn't in good condition, it holds the pushrod in place!
2nd question, i am going to get the rims respoked with stainless spokes. While apart i am going to clean and polish the hubs and rims. What advice can members give on process and products for a good and lasting result.
For starters I wouldn't use stainless spokes. They'll be larger gauge than original and cannot be bent as tightly, which can lead to them fouling the calliper. A new set of good galvanised spokes are probably going to look good for long enough that there's a real risk that the owner will be dead before they need replacing again.
Many an original Borrani rim has been ruined by overpolishing to a Chrome like condition with the original size engraving blurred by the process. They would have been a fine satin polish originally, rather than a high shine. Likewise the spoke flanges on the hubs. I tend to use a very light glass bead blast on the rims, followed by various grades of Scotchbright. The hubs also get glass bead blasted, usually at a higher pressure. I'll then often paint them with an alloy wheel paint which leaves them looking freshly cast, but with a longer lasting finish.
Where hubs and backplates have been polished (it nearly always looks crap, because you just can't do it properly), I'll grit blast to create a new as cast finish.