Piston replacement 07 EC250

[bchatt]

Decided to freshen up the top end - 120 hrs - I know, maybe a little late but still looking immaculate in there. The piston that is in there in one of these:

http://www.scottysdirtbikespares.com/products/878.html

Does any one know the significance of this "R" type. My bike is just an ordinary EC.
The thing is, I don't want to put in a "lesser" piston than I have now, if you know what I mean ( though these are quite a bit more expensive).
Any thoughts?

Thanks
Barry

[roostafish]

HOLY SCHNIKIES!!! That's one expensive chunk of aluminum! I'd just go with the stocker. It's also pretty expensive, but it's a lot less than that one!

Personal opinion here, Pistons don't need to be replaced nearly as often as we think. If it starts to lose compression, you should replace it, but if you're getting good numbers out of it, there's no need. Some will say that the skirt will fatigue, but that's only the case if the rings have worn, and it slaps the cylinder wall. These modern bikes with lined cylinders are amazingly durable. I marveled at my old Husky 125. I raced it for a season and a half, did nothing to it, sold it to my brother in law, who raced it for two years and did nothing to it, who sold it to another guy, who, after a couple of years, rebuilt it out of guilt, but it still ran, and runs fine to this day.

I also am a firm believer in 32:1 premix ratio.

[GMP]

What is the US/NZ exchange rate now? That price seems ridiculous, we are closer to half that here. A Vertex kit for a TM250/GasGas 250 is tha same for all years and works fine. I have never replaced a piston in a GG due to obvious wear, but I do it for piece of mind. Aluminum does fatigue, and for the price of a piston every year or so I'll take the insurance. I also like to avoid mid season repairs so if I'm close on hours I'll do it over the winter. 100 hrs is fine with good filter maintanence and premix, all of mine came out looking good. I also don't screw around with rings only as they always come out in spec. If I'm taking the time to tear it apart I'll do the whole job.

[bchatt]

Thanks Glenn. I agree - piston, pin, rings and little end bearing all getting changed. 120 hrs is a little long but the hours snuck up on me at the end!
The current exchange rate is $1 nz= $us .70, Scottys is an Australian crowd, so with that exchange rate makes one of those pistons $nz 438!!. I can get a vertex (thanks noobi) for around $nz 230, so I guess that's what I'll go for - I was just wondering about those "R" pistons and if anyone could say if they were so much better, or if they made a difference at all. It sure looks the part, and feels very light (nothing scientific, just comparing to an old KDX piston I have lying around).
It seems strange that the bike came that piston, also the bike came with a slightly shorter spark arrestor than other EC's I see- doesn't have the kink in the middle - dead straight.

[Trailrider]

The R stands for rip-off or more likely "Racing" and probably doesn't mean anything.
T

[GMP]

They don't say who makes it. I thought mine was an Athena. Over the years GasGas has used OEM pistons from all the major suppliers, Wiseco, Wossner, Vertex, Athena. Also, tha "2002 on" application is BS as all year 250s are the same.

[bchatt]

www.s3parts.com

Discovered this! My piston is an "S3" piston , made by this Spanish firm as in the link. I can only find a pdf catalogue with little clues on how to order or anything else!
This piston (the one that came out of the bike) is one of the nicest pistons I have seen. So, maybe Gasgas factory ran low and installed a few of these...who knows. I've already ordered a vertex and now I'm worried performance will be down on what it was with the S3 piston! (that would suck). I'll post result when the bike's going again.

[noobi]

I only know of these people who supply S3 stuff http://www.trialendurodirect.com/brands/15/.html

S3 are the people who supply the nambotin edition special heads, so it wouldnt surprise me if they have supplied parts before.
The longlife piston that is on the website I linked would cost around 260NZD + shipping. Still heaps cheaper than the one from scotties which would be ~500NZD by the time you got it here

[Keg]

Please do not click here if you consider this blatent self promotion.

http://www.mainjet.com.au/

[bchatt]

Got the bits on Saturday - thanks Noobi The vertex piston is in fact almost identical to the S3. The side "ports" on the piston are .5mm lower on the vertex but look to be the same depth and dimensions. The rings are .7mm lower (further from the crown) on the vertex. The vertex wrist pin is thicker.
I've got it all back together and it seems to run fine.