Yamaha TRX850 Enthusiasts Forum

Comprising information on various pistons and gasket thicknesses for reference so can someone please supply me with the piston dome volume of the JE 878 pistons???
The compressed gasket thickness for the std OEM Yamaha gasket would be of benefit too.
I may be wrong but I feel Mark ( Sandunes51 may have mentioned 0.76mm as the gasket thickness.

If my figures are correct, it will be around the 5cc mark.

http://www.csgnetwork.com/compcalc.html

Cobba

I have some numbers scribbled in the back pages of my Haynes manual. I will take a look.

0.6mm sprang to mind for the compressed head gasket but not an easy thing to determine accurately.

MrDW

Cheers for that,
My thinking being if the compression ratios are pretty close on different pistons,
So different profiles on the piston crown will equate to deeper or shallower valve relief's.
This there for would effect burn rate and all this will come into play with ignition timing.
How the Arias piston gains compression is by raising the deck height on the piston by 0.3mm which allows for an overall flatter top and shallower valve relief but I need to add a few calculations on a common head cc and gasket thickness to compare , so I have a really good understanding on what's going on inside the head and see if the dry run correlates with my maths....

OK I.ve established 0.9mm as the compressed head gasket thickness BUT
Does Anyone know the dome volume of the JE pistons????