83-87 YZ Piston Wristpin Location

[mx91a]

Does anybody know the location of the 83-87 YZ250 piston wristpin hole with respect to the 86 and/or 87-89 TRX piston? I know it is somewhere in between the two as I have read it requires either a 2, 2.5 or 3mm spacer plate with the 130.3mm rod depending on if and how much the cylinder has been decked. If someone has both a YZ and TRX piston and could measure the distance from the top of the wristpin bore to the top of the outer edge on each piston that would be very helpful.

Thanks

[C-LEIGH RACING]

Just from memory, not measurement, with a long rod crank & YZ piston, you would need the 2.5mm plate & 2 base gaskets for the piston edge to come up close to flush with the deck.

Old 85/86 TRX piston, 3mm plate & 2 base gaskets.

When measuring everything, pistons, rods & all, you would think by the thickness of the different spacer plates, that it would be like .5 of a mm difference in the location of the wrist pin holes in the YZ or TRX pistons, but its not.
Even the location of the wrist pin hole in the new model TRX piston not 5mm difference.
It can get mighty confusing trying to figure it all out.

Wiseco has a hot line you can call, to get all those measurements of the pistons.
Neil