650SS piston weight

elefantrider · Apr 17, 2022

Anyone know the weight of stock 650ss flat top pistons?

robs ss · Apr 17, 2022

elefantrider said:
Anyone know the weight of stock 650ss flat top pistons?

Mine are 224 grams (bare).
Not sure they are really OEM - they are GPM 6812 6822.
They are flat top with valve pockets.
Cheers

norton bob · Apr 18, 2022

Some replacement pistons have stupidly heavy thick wrist pins.

Stephen Hill · Apr 25, 2022

Removing material from the inside of wrist pins was sometimes done when tuning an engine for high performance. This was done on the outside ends of the pins which locate in the piston. The finished shape at each end is tapered to avoid stress risers. Might be worth considering if all you can get is replacement pistons with thick/heavy wrist pins.

acotrel · Oct 27, 2022

In about1963 I watched Jack Forrest beat all the Manx Norton's at Bathurst with a 650SS. He rode for BMW in Europe

Bernhard · Oct 29, 2022

Stephen Hill said:
Removing material from the inside of wrist pins was sometimes done when tuning an engine for high performance. This was done on the outside ends of the pins which locate in the piston. The finished shape at each end is tapered to avoid stress risers. Might be worth considering if all you can get is replacement pistons with thick/heavy wrist pins.

I have two types of wrist pins, thaose which have parallel inside bores, and those which have had a taper inside each end.

annajeannette · Mar 2, 2023

for 650 pistons were fitted with BHB 23270 LH and 23271RH The max bore size is 30 over the factory Manuel tell you to never go over this size now BHB pistons were manufactured for rolls royce engines so Norton only fitted the best available at the time

650SS piston weight

elefantrider

robs ss

norton bob

Stephen Hill

acotrel

Bernhard

annajeannette

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