Piston Help

[jaret10]

I tore the top end down earlier and was wanting to put a new top end kit in, I bought this bike used and would like to start with a fresh piston and rings to know where I am at as i begin to ride it.

Bike is a 2011 Six Days 300
Cylinder is stamped B
RB Head mod has been done by previous owner, and I am assuming Squish because there was only 1 Green Gasket on the bottom of the cylinder ( I have not measured it) I know that there is probably plenty of time left on this top end, just preference when I buy used I like to know where I am at.

The piston in it has this stamped on it:
Left: 10-15 19442
Right: S3 Vertex
Bottom: B 71.94

Cylinder looks good.
Piston wear is same all the way around.
Ring Gaps:
Top ring - .76 mm
Bottom ring - . 55mm

I have searched for Vertex pistons, cant find them. I assumed the 19442 was product # and their website brought up nothing.

Anyone know where i can get the same piston that came out of it, or another good quality dome shaped piston? The Weisco seemed flat topped and Wessner looked flat topped but haven't checked their site.

[Jakobi]

Give your local gg dealer a call. No doubt some on here will chime in with some info. I know GMP has been using the cast Vertex pistons and is happy with them. I'm currently running a forged Wossner in my 2010 EC300 and am happy with it also. I can confirm they do indeed have a domed top.

Its hard to judge the squish based on the number of base gaskets. Ideally you'll want to measure it up to see where you are and judge what Ron has done.

My personal preference is to set the port timing so the exhaust port is flush with the top of the piston at BDC. For me I require 1.3mm stack of gaskets to achieve this. Then with my S3 head and black insert my squish measures in at 1.8mm. Dropping 0.5mm gasket would tighten my squish some and raise compression some more, and also beef up the bottom end at the expense of top. I like the port timed to still give a strong mid to top with a softer bottom. It suits my riding style more.

All personal preference. Enjoy!

[jaret10]

Thank you, I will check that stuff today. I measured the gasket on it and appears to be .5 mm and seems like it has relaxed down closer to .3mm where it has been pinched from tightening down.