Here we are Ken, hope it is of interest.
I am interested in the following statement from the article:
....The isolastic mountings were dispensed with, only a damping rubber was retained for the cylinder head steady......
Any idea what was used? Where are the pictures referenced?
On my Seeley 850, the head steady is two short tubes with rose joints at each end. The ends at the rocker-box are held by shoulder bolts, which are in shear. The only way the top of motor can move when it vibrates is sideways. When that motor pulses, everything goes down the chain and drives the bike. With a 72% balance factor, the motor is dead smooth at 7000 RPM, and acceptably smooth anything above 4000 RPM. When the motor idles, the whole bike rocks backwards and forwards. If your motor can move backwards and forwards, you will crack the frame. The impact when it stops causes metal fatigue.
... for/aft pulsing...I have JSM extra long short stroke rods and pistons, balanced at high 70s rather than low 70s it is smooth throughout the rev range! Vibration is certainly not enough of an issue at the bars or through your feet too even think about changing the balance factor, unlike other rigid mounted Nortons I have ridden!
Stuart Garner sold the intellectual property rights of the Norton 961 engine to Zongshen in China, just before his company went into administration.. I wonder what the motors will cost individually ? With 90 BHP on tap, a Seeley or Rob North would be a real whiz.
Even 80 BHP would be good, and if it is 70 as standard., the rest might not be difficult. At least we would be playing with a new motor. If I lived in the UK, I would be looking for makers of after-market frames. Even an early Commando would probably accommodate that motor.There isn’t a 961 in the world with “90 BHP on tap” Al...
Al, there is already rules like that for some classes, pushrod motors and two Vv's per cylinder!