Can anyone tell me if a WD Norton Big 4 engine will go straight into a 16h frame without modification? It would clearly make a 16h more interesting to ride. Cheers. John

email (option): Tinley@btinternet.com

The Big 4 engine will fit (in fact any of the Norton SV / OHV engines will, apart from the 600cc Model 19).

It is a very tight fit under the flat-bottomed WD fuel tank (no chance of getting the plug out with the tank on).

Easiest way is with a pre-1938 Big 4 engine which goes straight in. If you use the 1938 WD type then you will need the magneto platform that comes with that engine (the later engine has a more widely set mag drive line).

I'm not actually sure that the extremely long stroke Big 4 engine will make for a sweeter and livelier solo than a well put together 16H but it will certainly have improved hill climbing ability, especially if heavily loaded. The big Norton engines are not revvers though.

The increased torque is pretty addictive though..Even if I ride a 350 or 500 OHV single it feels a bit lacking in its spread of power compared to the 720 SV..Although the OHV engines have more power (though probably not the 350s) it is how that power is delivered...As for my 720cc B33 it seems to have unlimited grunt..even with an engine sprocket 5 teeth over standard it will still comfortably pull away in second gear...Lovely, lovely torque..Ian

email (option): ian@wright52.plus.com

Hi John and Rik,

Rik you told me also a couple of months ago that you can make a early big4 piston in a 16H engine to improve it, is this something for you John??

regards,

Bram

email (option): bram@ockhuizen.com