Hello folks, about 3 years ago, I replaced the chrome cylinders on my eldo to gilardonis, but did not check the weight of the forged pistons in comparison to the oem pistons, so I decided to do that. I have put about 10K miles on the engine, and always have noticed a bit more vibration with the giardonis.
Luckily I still have the stock pistons rings, etc. I took out so I could weigh everything and compare.
Here is what I found:
OEM piston assembly . Right side =487g Left side= 485 g.
Gilardoni piston assy. Right side = 493 g. Left side = 492g.
both oem and gilardoni piston pins all weighed exactly 96 g.
I averaged the weight of both oem pistons to 486g.
Basically I had to remove about 6-7 grams of weight from the forged pistons, to equal the weight the crank was balanced to.
A dremel made it pretty easy to remove material from the inside of the pistons, mostly from casting ridges, and a thick reinforcing ridge along the bottom piston skirts, on the inside.
I was able to get both pistons to exactly 486g. of weight including the pins, circlips, and rings.
I also had a local machinist install new small end bushings in the rods, and they were reamed to fit the pins, and also re ground all 4 valves, and lapped them as well.
I removed a total of 13 grams of excess weight from the pistons!
Last night I took the bike out for a test ride, and all I can say is WOW!
What a huge difference this has made in smoothness! I can notice the difference at almost all rpms, but at my usual cruising rpms of about 3500-4000 it is buttery smooth, the mirrors no longer become "fuzzy" at different speeds.
I am very happy with the results, and it was kinda cool to take a peek at the engine innards to see how everything is doing after 10K miles.
I want to thank all you folks that so patiently help me , with my questions, especially Charlie!
Rick.