OK, Honda, mid 60's 5 cylinder 4/ 125cc.
turned 17 or 18krpm.
The piston, bare weighs 34g.
That's the 1966 , RC149.
Eight speed and 32hp at a whooping 19.500rpm.
Then there was the six-cylinder 250cc, RC166, pumping out 56.8hp at 17.500rpm
....prominently raced by Mike Hailwood in the 1966 World Championship,
where he won all ten races he entered.
...now, will ya look at that:
RC166 piston/rod
Weird video, but aaaawesome sound: CLICK
.
OK, the pic is of the RC146
1965 125cc basically a 3 cyl and 2 cyl motors cranks. The 3 cyl had 120° crank and the twin side was 180°
125 cc 4RC146 & RC148 1965 RC115 Honda
The 4RC146 is an improved version of the 2RC146, and nearly identical to it – the only external difference are the shorter exhausts of the 4RC146 (see pic 4RC146).
Power is now 30 bhp at 17,000 rpm. In actual practice, the engine hardly ever runs well, with continual Carburation and ignition problems.
Some interesting data: the piston, as usual for Honda with two compression and one oil scraper rings, weighs 34 g without the pin and rings. The pin, with a diameter of 11 mm weighs 11 g. An inlet valve has a head diameter of 14.5 mm and a stem diameter of 3.8 mm and is 74.4 mm long. Weight: 9 g. Two valve collets and the retainer weigh 1 resp. 3 g. Nobby Clarke said they used tweezers to put the Honda valve gear together.
The RC148 is the great surprise of 1965.
It is a five cylinder, in principle two and a half 50 cc twins.
Bore and stroke are 33 x 29 mm for a total capacity of 124 cc.
Drive to the camshafts is by gear train between the third and fourth cylinders. Power is 34 bhp at 20,000 rpm. There are eight speeds in the box, and the engine has wetsump lubrication.
The four exhausts of cylinders 1, 2, 4 and 5 sit in the normal place, left and right of the bike, the exhaust of cylinder 3 sweeps up and around the lefy hand side of the engine, crosses through the frame, to end up under the right leg of the rider.
Dry weight is given as 85 kg.
Sorry, this is what happens when you build 30 hp 80cc grenades. You find out what other junk has been built and don't clean up drive space.
John