Helium in the tyres
Interestingly, my road-going sps raised an eyebrow at the mot, as they thought it was the lightest 916-type they'd had in - I know the brake test scales arnt the best in the world, but they thought it was going on for 185kg.
Maybe it was the helium
I want to know what it really weighs now !
On a serious note - my velocette 350 racer had the centres drilled and dished from absolutely every bolt, and every metal bracket thet had a flat section had holes drilled in it. I think we worked out that it added up to about 2kg when I compared weights on the acu scales with another racer.
Note - no ti and lots of steel bolts, so it is the 'cheap' way of getting a steel bolt that weighs about what a ti bolt does.