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Meteor Pistons?

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I’m doing the top end of my 15 300RR RE (145hrs). The stock piston I removed was a forged unit from Vertex. I decided I wanted to be sure and keep the smooth running characteristics of stock and buy a big $$ stock piston from my local dealer. When I get it it’s not at all what I was expecting, it’s a Meteor (never heard of this company) and it’s a cast unit. After measuring my bore a A or a B piston would be fine so I went with a B that should measure 71.95 per the manual. This Meteor piston had a B stamped on it but the box states 71.98, that’s two sizes bigger than a C! I was not happy with this so I took it back to the dealer to ask about it. He said this is the piston Beta is sourcing now and no longer getting forged Vertex units. Hmmm, I was not going to pay $250 for a cast piston I’ve never heard of so I gave it back to him. I have no issue with cast pistons, all my other 2-strokes have been rebuilt with cast with wonderful results, but not at that price! I came home and ordered a cast Pro-X unit for a lot less $$. Did I make the right call?

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When I did my top end on 17’ 250rr, the piston I got was a vertex KTM piston.

With that said I have always had good experiences with Pro X stuff. I have never used one or there pistons however.

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The size difference is enough IMO to cause concern.   If it's not correct on that spec, what other spec is wrong?   IMO you made the right choice

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Check Meteor's catalog, they offer a forged and a cast piston for Beta but the forged A is 71.94 and the cast 71.97 (as you already discovered). 

Innteck Italy have both at the same price (about 130 euros +vat) which should be lower than Vertex. I don't know if Innteck USA sells them. 

The pro-x piston is little heavier than the oem, don't know about the meteor. 

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You could have ordered a replace Vertex piston from Motosport.com or Chapmoto.com  I'll probable buy a Vertex piston when I freshen up my 300RR top end.  

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7 hours ago, David37 said:

You could have ordered a replace Vertex piston from Motosport.com or Chapmoto.com  I'll probable buy a Vertex piston when I freshen up my 300RR top end.  

David; you must be talking about using a KTM piston as I do not find anything for Beta.

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Check Meteor's catalog, they offer a forged and a cast piston for Beta but the forged A is 71.94 and the cast 71.97 (as you already discovered). 
Innteck Italy have both at the same price (about 130 euros +vat) which should be lower than Vertex. I don't know if Innteck USA sells them. 
The pro-x piston is little heavier than the oem, don't know about the meteor. 

Can you vouch for meteors quality? I have never heard of this brand. What about using a 71.98 when the manual calls for a 71.95? Is this ok if the material is cast instead of forged?

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15 hours ago, mountainmanid said:

Did I make the right call?

Yes. $250 for a replacement two stroke piston is silly. I put in a Wiseco piston for a KTM 300 (2016 model) in my 15 Beta 300RR and it runs great. I recently bought a Pro X piston for my KTM but the cool thing is I can use it in either bike. I bought it in December from Rocky with a 10% off so total was $90. :banana:

I change my pistons around 100-125 hours based on blow by visible. Only have 38.5 hours on my Wiseco now and it already has blow by so I think my cylinder is becoming out of round. May need a replate next. Have 204 hours total now.

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3 hours ago, mountainmanid said:


Can you vouch for meteors quality? I have never heard of this brand. What about using a 71.98 when the manual calls for a 71.95? Is this ok if the material is cast instead of forged?

No experience yet but I plan to install one (forged) soon. 

It is an old company (more than 50 years I think) and it seems that they are entering the moto industry now. I saw them for first time in the 2014 EICMA m/show and since then they are present every year. 

I think Beta has started working with them as well. 

Regarding the A-B-C dimensions being different between forged and cast pistons, the only reasonable explanation I can think off is that when you need a bigger piston than C (due to bore dia wear) then you continue with a cast A. 

I would send them an email asking for more details though.... 

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The different sizing is probably due to the different heat expansion characteristics of cast pistons vs forged ones.  That said, it's ridiculously expensive. I've been running forged Prox in my 300 & it's excellent, and much better priced too. 

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The different sizing is probably due to the different heat expansion characteristics of cast pistons vs forged ones.  That said, it's ridiculously expensive. I've been running forged Prox in my 300 & it's excellent, and much better priced too. 

I thought the Prox was cast not forged. Their website states it’s cast. Is there another prox that is forged?
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7 hours ago, tim2007 said:

The different sizing is probably due to the different heat expansion characteristics of cast pistons vs forged ones.  That said, it's ridiculously expensive. I've been running forged Prox in my 300 & it's excellent, and much better priced too. 

This crossed my mind as well but don't you think that 0.03 clearance is too tight? 

Regarding price, 130 euros is about 150 USD. 

The 250 asking price is hard to justify..... 

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IMG_9268.jpg

This is what I’m running in my 250rr.

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IMG_9268.thumb.jpg.66ed15d3d9e855f988159c0a05dabd6c.jpg

This is what I’m running in my 250rr.

I wish the 300 had such a easy crossover like the 250. Many say the KTM piston will work, but I’m picky and need more than a guy on the internet said so...

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1 hour ago, mountainmanid said:


I wish the 300 had such a easy crossover like the 250. Many say the KTM piston will work, but I’m picky and need more than a guy on the internet said so...

Should I take a pic of my box? Lol. Though I think I tossed away my wiseco box but I have the pro x box. 

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Should I take a pic of my box? Lol. Though I think I tossed away my wiseco box but I have the pro x box. 

It’s not just you that it works for, and I’m not doubting you. I’m just very particular and need documentation, it’s me.

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On 4/20/2019 at 8:56 AM, shrubitup said:

I change my pistons around 100-125 hours based on blow by visible. Only have 38.5 hours on my Wiseco now and it already has blow by so I think my cylinder is becoming out of round. May need a replate next. Have 204 hours total now.

You must really hammer it. I replaced the piston on my GasGas 300 at a bit over 400 hours and it was only down around 10 lbs. I'm now seeing about a 10 lb drop on my Beta after 300. I mostly ride tight trials though.

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26 minutes ago, Ud_Luz said:

You must really hammer it. I replaced the piston on my GasGas 300 at a bit over 400 hours and it was only down around 10 lbs. I'm now seeing about a 10 lb drop on my Beta after 300. I mostly ride tight trials though.

Also ride slow tight trails. Don't hammer it but motor has to pull a heavy load (me). I suspect it was out of round when I bought it from previous owner's usage. Bike didn't seem to have that many hours on it when I got it but when I pulled the piston is was charred black everywhere meaning there was little ring seal.

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55 minutes ago, shrubitup said:

Also ride slow tight trails. Don't hammer it but motor has to pull a heavy load (me). I suspect it was out of round when I bought it from previous owner's usage. Bike didn't seem to have that many hours on it when I got it but when I pulled the piston is was charred black everywhere meaning there was little ring seal.

Interesting. I wonder if they hadn't been good about air filter maintenance? 

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