by john webster » Sat Sep 03, 2011 2:25 pm
hi larry.yes it has 1 intake and 2 exhaust ports.this engine is 250cc 2 stroke and was primerally used for road racing in the uk in the roaring twentys then this machine was developed by allen and simmonds,who where the first people to produce a pedestrian garden tractor in 1926 this model was produced for ten solid years and when i have it restored it could possibly make big money. the serial no is 530 and as far as i am aware it is the oldest one surviving up to now. larry this model is a MK 25 A thats where you have got it mixed up cheers