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need some opions going to replace pistons should i go with the forged, i will be spraying nitrous also- looking for some opions
 

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yeah you could run forged w/nitrous. i suggest you run oem they are a very good piston.i run oems in my dragger and they never gave me an
y problems.
 

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ITs WINTER!
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Forged would be the best piston to use if your spraying, and you have to make sure its fully warmed up EVERY time you ride it or your going to squeak it in a hurry!
 

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use OEM pistons or SPX moly coated they work great I have OEM in my 800 Power TEK and spray about 20 bottles a winter and never had a problem.

What brand of Nitrous system are you installing?
 

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there is no question that a forged piston is stronger, especially if you spray or huff the motor... but like said above, that motor better be fully up to temp before you get in the throttle or you will cold seize is quicker than anything... going forged requires you to take better care in your warm up procedures, but that are much tougher pistons...
 

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GSX800LTD said:
OK, one more time. Forged pistons are for 4-strokes, CAST pistons are for 2-strokes.
[snapback]741963[/snapback]​
I would really like you to explain to me the reasoning in that statement that you made. Were you joking?...............
 

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milrlite said:
GSX800LTD said:
OK, one more time. Forged pistons are for 4-strokes, CAST pistons are for 2-strokes.
[snapback]741963[/snapback]​
I would really like you to explain to me the reasoning in that statement that you made. Were you joking?...............

[snapback]744454[/snapback]​
I'll be happy to. (I wasn't joking) Forged pistons are indeed mechanically stronger than cast. This is great for high revving and/or force fed 4-strokes. The issue is, two stroke pistons typically don't fail by breaking, but rather by melting. (they may break up as the engine destroys itself after the melt) They melt at the edge of the crown near the exhaust port, or a hole in the center. The problem with forged pistons is they have a greater thermal expansion rate than cast. So the popular theory is to give them a loose fit and they tighten up when the engine warms. Except it's not quite that easy. They tighten up enough to stop (most of) the rattling as they warm up, but they still are too loose to EFFICIENTLY TRANSFER ENOUGH HEAT TO THE CYLINDER WALL. This goes along sorta OK until the chips are really down.... cold temps, long WOT run, poor fuel, etc. and then the heat being put into the crown by combustion temps rapidly exceeds the forged pistons ability to transfer that amount of heat into the cylinder wall for removal. The pistons crown melts and thus the failure.
The cast piston has a much smaller expansion rate, the cylinder to piston clearances can be held tighter and the ability to RELIABLY TRANSFER HEAT TO THE CYLINDER IS MUCH GREATER. THUS A GREATER RESISTANCE TO FAILURE.
All OEM two strokes are equipped with cast pistons because they are the best choice for the application. Forged pistons aren't that much more money to produce and if they (the engineers) thought for a second it would save a few warranty claims from failures, they would be in there. THEY ARE NOT.
I know this will not be well accepted by the large number of "Bling Captains" that inhabit this site, many are sadly convinced that "anything aftermarket is more expensive and therefore BETTER". Wiseco has been taking the money of people rebuilding two strokes for years. Great business for them. Bad choice for the engine's owner.
Use them in your 4-strokes and have a party, they work fine.
 

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FAQ man
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Back in 1997 I had a motor rebuilt by Rich Felagy (sp?), at the time he was a very well known mechanic and used to build motors for several snowcross teams.

Anyway, I will never forget what he told me when I asked him about Wiseco pistons...he said, "I wouldn't run Wiseco's in my fu%&ing lawnmower."

Made me chuckle when he said that.

Jerry C.
 

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pete24 said:
gsx800ltd you are full of crap and are no mechanic!
[snapback]744885[/snapback]​
I think I find his argument a bit more convincing, tho - and with a little knowledge of metals, you might too
 

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pete24 said:
gsx800ltd you are full of crap and are no mechanic!
[snapback]744885[/snapback]​
do the research before you knock someone....
 

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doesn't the amount of different alloys that are put into forged pistons affect their expansion rate also? I think they even add silicone to the mix....right? When I rebuilt my SRX 700, I used Wiseco forged pistons and had great luck with them. Sled now has 1500 miles since rebuild and still runs strong.
 

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I have 2,800 on my Cudneys with no issues. I look at it this way. If a motor is going to go down what do I want to be the weakest link? I would rather loose a piston then have the piston survive to the point that crank goes do to too much heat build up or a castostophic piston failure taking other things out like a cylinder or rod. I may be talking out my [email protected] but that's my theory.
 

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mopar1rules said:
doesn't the amount of different alloys that are put into forged pistons affect their expansion rate also? I think they even add silicone to the mix....right? When I rebuilt my SRX 700, I used Wiseco forged pistons and had great luck with them. Sled now has 1500 miles since rebuild and still runs strong.
[snapback]746317[/snapback]​
That's silicon, no "e" and it's in every aluminum alloy to varying degrees. I see you're having good results with the Wiseguys in your Yam, that's good. I'd also bet that your other variables are well inside the safe zone... ie, jetting that's fairly conservative rather than ragged edge lean. So the piston crown temps stay comfortably away from the failure point. Buuuutt.... if you take it across the lake at -25F, and the gas you got was not very good, and someone dumped methanol alcohol in it (the gas) before you bought it...... then you may aproach the temps where the difference would become an issue. Seeing's how that's pretty unlikely, they'll probably live a long happy life.
People tuning their engines right to the crispy edge with lean jetting are more likely to bump into that melting point.
 
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