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Which Piston?

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Theirs a lot of threads about which to use ( forged & cast ) I prefere the forged, less proe to cracking, weisco...

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I trust my local dealer guys because several of them have been through MMI and they ride too. They said they use Vertex - so that's the piston I went with for my winter rebuild. They said that Wiseco pistons REQUIRE a warmup each ride or else you'll have a problem. I'm new to this and am only passing info on that I've been told...

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They said that Wiseco pistons REQUIRE a warmup each ride or else you'll have a problem.

That they do. But I would still let a vertex, oem, etc. warm up.:thumbsup:

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I trust my local dealer guys because several of them have been through MMI and they ride too. They said they use Vertex - so that's the piston I went with for my winter rebuild. They said that Wiseco pistons REQUIRE a warmup each ride or else you'll have a problem. I'm new to this and am only passing info on that I've been told...

MMI... :thumbsup: Don't all motorcycles need a warmup? I swear some people

Isn't vertex just a relabeled oem type piston anyway?

No. Pro-x and OEM are the same. Vertex is a higher quality casting than OEM but still prone to cracking like OEM. Vertex also is selling Wossner forged pistons now under the Vertex name.

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I trust my local dealer guys because several of them have been through MMI and they ride too. They said they use Vertex - so that's the piston I went with for my winter rebuild. They said that Wiseco pistons REQUIRE a warmup each ride or else you'll have a problem. I'm new to this and am only passing info on that I've been told...

Warming your bike up before you ride should be everyone's requirement, regardless of engine internals.

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No. Pro-x and OEM are the same. Vertex is a higher quality casting than OEM but still prone to cracking like OEM. Vertex also is selling Wossner forged pistons now under the Vertex name.

Ahhh... got it, for some reason I had a brain fart with the whole "x" part.... haha

Thanks for the clarification.

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I just installed a Namura in my 04 cr250. SO far so good. I normally would run a PRO-X OR VERTEX.

-I know Namura has gotten some bad reviews, but I talked with the company, they seemed pretty confident I could get 20 hours no problem out of it. I race A-Class MX and thats about all I'm willing to put on any brand of top-end. I'm gonna pull it apart at 10 hours, and put a fresh set of rings on, then rebuild at 20.

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Thanks guys I have just ordered a Vertex piston kit, I have heard about drilling the front of the piston inline with the exhaust bridge port? As anybody do this? What is the benifit?

Cheers

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Drilling in the skirt gives more throttle response=more bottom end. And yes it also helps lubricate exhaust bridge also.

Edited by MX926

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Yeah it's just a lubrication thing. I don't think you have to drill the Vertex pistons though, do you? I thought it was just a Wiseco thing...

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You don't have to drill the holes in any of the pistons, Wiseco just recommends it. I do drill.

For pistons, I'm a Wiseco man. No piston lasts any longer than anybody else's, the Wisecos are just less likely to fail catastrophically if you exceed the wear limits (piston to cylinder clearance). Forged pistons are tougher than cast pistons and can handle excess wear and detonation better. They do exhibit higher coefficients of thermal expansion and may not tolerate a hot running piston as well. This could be caused by lean operating conditions or excessive ring wear. I never wear my rings out before my skirts are way out of spec.

As for warm-ups, you can't really warm-up a 2-stroke. They barely make any heat at idle because they pump so much excess fuel and air through the cylinders and fire only once every couple of strokes. Letting the bike "warm-up" just loads the engine up. Start it, let it warm up until it revs cleanly without the choke (unless it's really cold, this is only a few seconds), put the bike in gear, and start riding it. I don't mean hold it to the pin immediately but get on the thing and start riding it up and down the road while you wait for your buddies to get their gear on. Then, hold it to the pin to get it to clear out. Funny thing is, if you trail ride your bike, long periods off the throttle will bring the temperatures of the engine so low that the bike has to go through the whole warm up process every time you get back on the throttle.

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