Finally got to the bottom of my breathing problem; a bit of a Eureka moment as I realised what has been happening.. The non-return valve in the timing chest consists of a brass plug with a vertical drilling. The ball bearing sits on a seat formed by the bottom of the drilling being smaller than the ...

Thanks for the info all.

Turns out the bike I was wondering about has an asking price of around £14,000
out of range for me.

Cheers

Huw

Anyone like to give an opinion as to what to pay for a 1926 model C in good nick with all it's correct bits?

Shifting a bit off topic here, but didnt Ariel produce a limited number of Bronze head Red Hunter race bikes in the mid thirties? They certainly produced the parts. The only evidence I have so far are the brief references in Lawrence Hartley's book and more convincingly the picture in the book 'What...

Good to see it's got the Ariel 'three point' sidecar frame. Pretty rare that. ( and heavy!)
Not too bad value considering that it's Verrals and that it's a proper Vintage combo.

Anyone know what an 87.7 mm diameter cast iron W & P piston comes from? As I understand it the std. size for 3.5 HP singles was 85mm up to 1912 then 86.4mm and no oversizes were available? I've searched through the site documents but it seems all the v-twins and the 4HP single were smaller bore ...

Thanks for that Pat It seems to me the breathing was steadily improved over the years. I'll post some photo's of my early cases when I get back home in a weeks time. Interesting what you say about the tappet bushes; the bike has been far more prone to throwing out oil since the rebuild and these wer...

Well so far, all I've discovered is that neither of the crankcase pairs I have feature in any of the parts books drawings from 1911 to 1925. The breathing on the 1912 pair is by tiny breather and ball bearing in a brass plug above the inlet cam and has a pipe that vents to atmosphere. I have also se...

just looked over this thread; please forgive my daft mistakes. For magneto chain please read cam gear and the n6 plug should of course be A6...

Still trying to fathom out the mysteries of W&P breathing and why my engine isnt quite right, more soon.

I thought so as well Adrie but the plug couldn't look healthier or work better. No signs of excess oil past the piston at all. Its a Champion N6. There are no vents of any sort on the drive side of either of my pairs of crankcases. Both have the small hole and ball which vents to the timing chest. A...