What "size" piston without removing barrel

[Eugene]

Is there an easy way to determine which letter piston is in your bike without removing the barrel? I have heard that GasGas stamps a letter on the barrel area just above the intake, but my '06EC300 has no letters, only numbers. My piston has now run a year with about 3900km's on, and while I can feel no power loss, it is probably time for a new setup. Do Vertex and Athena sell piston kits through the net, or are there any delaers on this site who sell them?

[ramcclure200]

Eugene, I'm not sure about the letters but if your looking for a vendor I would suggest GoFasters.com. Give them a call or E-mail.
Ron McClure

[GMP]

They are stamped on the rear of the cylinder just above the base. If the cylinder is on the bike it may be hard to see, try an inspection mirror.

[AMCQ]

Originally Posted by GMP

They are stamped on the rear of the cylinder just above the base. If the cylinder is on the bike it may be hard to see, try an inspection mirror.

Need some help to work out what size my cylinder is. The bike is a 2003 EC200, and it is getting its 1st top end rebuild after sitting unused for 4yrs.

I read the quote that the marking should be on the back of the cyl, but GasGas uk tell me it should be below the exhaust port! But when I look at my cyl, there is no marking stamped in either location!

There is a pen marking on the base gasket face which says 5A or SA, and a small stamp to the side of the exhaust face but it looks like a logo JAP in a oval.




The only clue i can find is top of the piston is marked 62.45mm.


So from that should I assume this is an A piston, as I read somewhere that the sizes are 62.45, 62,46 and 62,46

[Leo]

Be careful with go faster if you is from outside US.
I'm not happy with them since i not received my parts and anyone replied my emails.

Go to Ebay.

[PEB]

The size is on the carb side of the cyl. stamped on the flat area. Should be an a,b,c or d. Keep looking it is there.

[iancp5]

Originally Posted by Eugene

Is there an easy way to determine which letter piston is in your bike without removing the barrel? I have heard that GasGas stamps a letter on the barrel area just above the intake, but my '06EC300 has no letters, only numbers. My piston has now run a year with about 3900km's on, and while I can feel no power loss, it is probably time for a new setup. Do Vertex and Athena sell piston kits through the net, or are there any delaers on this site who sell them?

I doubt you will need a new piston unless your terrain is such that you're running wide open a lot and getting muck in. I'd check it out before ordering one probably a quick hone and new rings will make it as good as new.

[GMP]

I do the piston and rings, reeds, and clean the PV off season. That way I'm sure to be good for the next season with no mid year down time. Pistons not only wear they fatigue as well.

[Eugene]

On my CR250 and 01EC300, I had pistons with cracks in the skirt after 2 seasons, so since then I change the whole setup. A piston is cheaper than a new barrel/nicasil coating when it all goes pear shaped. I emailed the GoFasters site yesterday for some bits for my '06 300 and 450, but haven't got an answer yet. Do they sell the coated Athena piston, or only the Wiseco listed on their site? Is there a problem with their website, or are they just out riding

[gasIdaho]

I use GoFasters alot for parts, etc...as well as great technical advice. Give them a call instead of going thru the website or email...much faster response. They are very good about shipping quickly. I just got a new piston kit for my 05' EC300. It is a Vertex which I guess is OEM. I have an 'A' cylinder so I got a 'B' piston.