This is a 71mm (350cc) piston to fit Norton 71mm x 88m late type (1956-59) 350cc Model 50 singles - from well known piston manufacturer - JP Pistons.
We normally keep a minimum of one piston in stock for each of the following Bore sizes - +20 Thou, +40 Thou and + 60 Thou, and may also be able to obtain STD size piston by special order. Please state which bore size you require in the order Comments section when placing your order (we will email back to confirm availability).
These pistons are CNC machined and very well made, they are cast pistons not forged (as per our Omega racing pistons).
This particular type is as was fitted to the 1956-59 Model 50 engines (original part no L13/702 superceded by part number 19417), and in that engine according to JP will give approximately 7.3:1 compression ratio (however it is often worth checking this, and valve cutaways do not foul valves etc when fitting - as sometimes engines can have been modified in the past).
Please note that the distance between the top point of the Gudgeon pin and base of piston crown is approximately 35.0mm. This is significently more than the distance on SOHC 350cc pistons (and possibly pre-war Model 50 engines - I no longer have a pre-war 350cc OHV engine, so cannot check).
Therefore, please check and confirm the height of your old piston/engine and confirm this is suitable for your engine before ordering - unfortunately once trial fitted, we will not be able to accept it as a return.
Weight of piston without rings or circlips fitted is 450g, again this should be checked against orginal, as different makes in the past varied - and if very differnt, some re-balancing may be required.
For those looking for SOHC 350cc (Model 40 International) pistons - sorry, but JP do not offer a piston suitable for this model - I do have original Hepolite patterns and am considering having a batch manufactured - please email at firstname.lastname@example.org if you wish to enquire.
Note: These pistons are only available in small batch's. We can sometimes obtain them in different bore sizes - but please email as soon as you have a requirement, as we have to obtain them by special order, and some sizes may not be available for long