High quality inlet (or Exhaust) valves manufactured by G & S Valves for later SOHC 30M/Manx heads fitted with 5/16" stem valves. Available in 2 valve head diameters and 2 stem lengths.
These valves are 5/16" stem diameter and are of the type fitted to some later Norton SOHC Manx heads, or early DOHC (pre-Featherbed) heads. Unlike earlier SOHC heads - which were fitted with 11/32" stem valves on the Inlet side and 3/8" stem valves on the Exhaust side - the later SOHC (and then DOHC heads) would have 5/16" stem valves on both Inlet and Exhaust side.
We can offer these 5/16" Stem diameter valves in 4 variations:
0034a: 1.750" Valve Head Diameter, with the valve length (with cotter groove) of 4.545" overall length (which was copied from an old genuine Norton valve length)
0034b: 1.750" Valve Head Diameter, with a blank valve stem (overall length 4.875"), so the valve stem can be cut by the customer to the correct length for their cambox (i.e. either SOHC of DOHC type cambox)
0034c: 1.790" Valve Head Diameter, with the valve length (with cotter groove) of 4.545" overall length (which was copied from an old genuine Norton valve length)
0034d: 1.790" Valve Head Diameter, with a blank valve stem (overall length 4.875"), so the valve stem can be cut by the customer to the correct length for their cambox (i.e. either SOHC of DOHC type cambox)
I gather when they were fitted - the same stem diameter were fitted to both Inlet and Exhaust valves (I would expect it was more normal to fit the bigger head size to the inlet valve).
We can also supply 5/16" SOHC/DOHC type collets to fit our valve cups (see Item 0280 and 0040b). However, we do not currently supply 5/16" valve guides - but email us at sales@racingvincent.co.uk if you require them - we may consider having a batch made in the future (this update being Nov 2021).
If you wish us to cut the valve to length and machine the collet groove, please email seperately with order, dependent on how busy we are, we do sometimes carry this task out on our CNC- expect £12 charge per valve, and turnaround time of at least 3 weeks.
Note: as well as fitted to some late SOHC (Gardengate) Manx heads, this size of valve stem may also have been fitted to early DOHC Manx Longstroke engines. You will need to check your valve stem length, but you may find the blank stem versions of these valves could be fitted to this model of engine - you will need to check your machine.
Your basket is empty.
