250 EC Piston

[pbspecial]

I have a Vertex piston kit that I bought years ago when I was ridign a 98 EC 250 and never used it. It's been in the original box in my tool box for years. Does anyone know if this piston kit will still work in a 2003 EC 250 or even a 2010 250 GasGas?

Stamped on the top of the piston is 7W 66.350 and on the side is Vertex 1122.

Any thoughts?

I'd like to keep it for my new 2010 if needed or sell it to the owner of my 2003 if it will not work in the new bike.

Thanks

 

[roostafish]

That's a great question. I'd be willing to bet that it will work, but it may be wise to measure the two dimensionally to see.

Even if you don't get a definitive answer, I'd keep it, and if at some point you need to put a piston in your new bike, compare them. It's already paid for, and it's likely to work. My opinion, and I'm a penny pincher.

By the way, PB special? Lead special? What does your screen name mean? Just curious.

 

[jostby]

The original piston that I removed from my '00 was 66.33 My cylinder was stamped "A". I would guess that the piston you have would be a "C" oversize if meant for original. On my first piston swap I installed a "B" size Athena and it was 66.34 I know somewhere back during this timeframe the engines were manufactured by TM and I'm not sure if the pistons were different or when GG started using their own design. Next time you have a piston out I would compare dome height between the two. Use the wrist pin and hook them together and compare the height at the top. That and the cut-out on the bottom for the crank clearance will be the most important thing to check.
Then, different pistons (Vertex, Wiseco, Athena) require different piston to bore clearances depending on if they are forged or cast. I think the Wiseco's need more clearance but I may be wrong. I would call a Vertex rep and ask what kind of clearance is required for that particular piston. With the correct tools and knowledge it takes a matter of minutes to check clearances and shouldn't cost you more than $20 if you can't do it yourself. Considering a new piston is $200 +/- it is well worth the effort.

 

[jostby]

By the way, PB special? Lead special? What does your screen name mean? Just curious.

Yeah, inquiring minds want to know

 

[roostafish]

Trivia. Gas Gas started making their own engines in '97, at least I think that was the first year. I know for sure that '97 is a Gas Gas built engine because that is the first Gas Gas I ever rode. I previously saw a TM engined Gas Gas at an ISDE qualifier. I remember it was cool.

 

[Silver]

Don't know if this helps but the piston I took out of my 07 has 1122 stamped on it also.I have a "B" cylinder.

 

[GMP]

The piston will be fine, all years can use it as long as the clearance is reasonable. I've used them in all my GG 250s from '00 to '07. It will also go into a TM250 motor, as it was (is?) the OEM TM250 piston. The only concern when switching piston brands is if you have the head modified for a tight squish band with one brand of piston, be sure to check it if you switch brands. Most are close but it pays to check.