If you look at the cylinder head you can see the cooling fins run the wrong way, the engine is one from a CLIFFORD rotovator hence no cush drive also strange! magneto. Also the guy says he lent the timing cover to a mate , he obviously runs a clifford engine too in his bike 
Dave..
Dave has that one dead right...it is a Clifford motor from a rotovator. The Clifford engine has a different mainshaft on the drive side so it is not possible to 'retro fit' the shock absorber assembly. The bike probably ran like this at some point...the Triumph 4 spring clutch has a shock absorber built into it and was no doubt fitted to compensate for the one not present on the engine.
The timing cover is completely different to a standard motor with a 'hand cranking' facility cast into it and other detail differences. They had 'BSA Clifford' cast into them. The magneto is fitted with an 'inertia start' mechanism to aid starting. The mag straps were also altered to suit the 'mag only' set up. From memory there are also some differences in the crankcases where the mag fits through them...if anyone wants to confirm that I can check out the one I have in my workshp!
Head fins run the opposite way because the Clifford M20 engine was enclosed in metal housings and fan cooled by an impellar mounted on the drive side which blew air across the head. There might be some cooling issues without that.
Clifford motors can be a good source for barrels if bought cheaply..being fully enclosed they rarely have fin damage or bad corrosion and are frequently still on a standard bore size...I guess you don't do THAT many miles with a rotorvator!...The barrel is identical to the motorcycle one, and there are other internal components that can be utilised.
It might be the timing cover has been 'lent to a friend' to make it less obvious this is an industrial version of the M20...I wonder if the current bidders have noticed?....Ian
email (option): ian@wright52.plus.com
CLIFFORD rotovator
Funny, does it say "800cc" under barrel?..
email (option): noam10@gmail.com
Nice one Noam!...the beast in the flesh! ...I don't think it does say 800cc under the barrel..it is not entirely clear...However, the Clifford motors are 500cc so if it does it isn't a reference to cylinder capacity...Ian
email (option): ian@wright52.plus.com
Hi dear Ian,
It's something I found on the web and kept...
It is was mine, parts would go long ago to a frame I have waiting..
email (option): noam10@gmail.com
Shame on you Noam...If I had a complete one I'd use it on my vegetable patch.. ...Ian
email (option): ian@wright52.plus.com
Hi Ian,
I live in Tel-aviv on 2nd floor out of 8.
I have vegetable patch only no "National Geographic"
email (option): noam10@gmail.com
I've got a Big 4 engine out of a Trusty Tractor, which has the head fins the other way etc. The hand crank is on the drive side along with a fanned centrifugal clutch.
It would originally have looked like a motorised plough with the engine at the front and 2 long handles at the back. The bloke I bought it off stopped using it because he had the revs up a bit high and did a turn using the levers on the handles, which turned on the spot, throwing him into the hedge It stood until the scrapped the tractor and sold the motor complete with oil tank etc. I was going to get it running as a stationary engine, but I can't get the head and barrels off and the fins are very thin and fragile.
email (option): horror@blueyonder.co.uk
Hi Horror...I got the engine out of one of those from a farmer near me. It was in the hedge at the side of a field quietly mouldering away. He kindly dragged it out with his tractor and said if I removed the engine I could have it for nothing. It was a monster of a rotovator..with a chain driven 'dog clutch'gearbox behind the engine.
Although very rough externally the engine yielded some very nice, lightly worn parts which will be going into the engine of Rob Millers Big 4 outfit.
If that is what you found I don't think that is the 'Trusty Tractor'..I believe they had four wheels and were literally a miniature tractor.
Don't quote me though...I am not an expert on Norton agricultural machinery...thank God!
I'm sure someone will confirm whether that is correct...Ian
email (option): ian@wright52.plus.com
Against my better judgment I Googled 'Trusty Tractor' and it appears there were both two and four wheeled versions...though I'm not sure I really wanted to know that.. .. ...Ian
email (option): ian@wright52.plus.com
Well done Ian, you're becoming quite the Norton agricultural expert
I very nearly bought a restored 1935 Norton 4 wheel Trusty Tractor last year. I was going to get it road legal, but then found out it had a max speed of 15mph and was a pig to drive and stop. Ok for a field but not on the road with modern traffic. The bloke had done an excellent job doing it up, but couldn't sell it.
The other engines used in Trusty Tractors were 5hp JAP and Douglas. The Norton was by far the most powerful with 14hp (wow)
email (option): horror@blueyonder.co.uk
('but then found out it had a max speed of 15mph and was a pig to drive and stop.')
So like a 16H but 30mph slower...
..Maybe we should organise a race between a two wheeled trusty tractor and a BSA Clifford..Hold on to your hats!
...Ian
email (option): ian@wright52.plus.com
So like a 16H but 30mph slower...
Ian ...or like an M20 but quicker up hills !
I have owned both trusty & clifford M20 rotovators. The trusty was a douglas powered one which is the better engine but a hell of a handful to handle.The BSA clifford was unstopable you could set the depth bar for the rotors to the lowest positon and this thing would still chug even if you put the thing against a tree it would not stop but just dug itself in deeper.I have a set of cases for a clifford also a timing cover just in case the lucky buyer reads this forum..Dave...
I'd like a good cylinder head for a Clifford if anyone has one...Ian
email (option): ian@wright52.plus.com