- High quality inlet valves manufactured by G & S Valves - Following Head Sizes available (check your original) : 1.750 or 1.790". Valve stem diameter : 5/16" valves were sometimes fitted to late SOHC Manx engines and early DOHC engines.
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).
Stem length: 4.545" machined for 5/16" collets to fit our valve cups (see Item 0280 and 0040b).
Also we have both valve head sizes with Blank Stem available (i.e. left blank at end, so these can be cut to the same length as your original, and then the collet groove machined afterwards. This is the best way to ensure that you will have a valve the correct length for your cambox and spacing between cambox and head, particularly important if you are replacing a valve with a more obscure length. This type requires you undertake the final cutting to length yourself. If you wish us to cut the valve to length and machine the collet groove, please email seperately with order - 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.
15/12/18 - I am pleased to update that we have just had a new batch of these 5/16" stem valves made (they have been out of stock for some time), but note - only limited stocks, so advise you order quickly, thx.
The current photo is an old photo showing a blank stem 5/16 valve, but we will be updating the listing in the next 2 weeks to show each variation seperately.