Thoughts on top end parts

Dan Coburn

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Jul 3, 2017
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Hey just wondering what you all think about non weisco top end parts. I've been told to stay away from the eBay and Amazon cheap kits, which I will.

What's your favorite Piston and or rings that aren't weisco? And why?
 
What about namura? Sure I spelled it wrong. Is wiseco really the only decent option? As a snowmobiler we used other than factory or wiseco with great results.
Now I do realize this is a single cylinder air cooled motor, it just seems like there should be more out there.
 
You can run whatever your heart desires, but all of us will tell you wiseco piston is the only way to go. Cheap parts are not good and good parts are not cheap.
 
Really?
As a KTM guy I have always looked at Wiseco as second rate.
Much more prone to cold or heat seize and noisier running due to their greater expansion factor.

I would much prefer a Wossner over a Wiseco in my KTM or Seadoo or snowmobiles over the past 40 years.
 
Really?
As a KTM guy I have always looked at Wiseco as second rate.
Much more prone to cold or heat seize and noisier running due to their greater expansion factor.

I would much prefer a Wossner over a Wiseco in my KTM or Seadoo or snowmobiles over the past 40 years.
This is what I'm talking about! In sleds we didn't like them much either.
 
I ran a Namura piston for well over a year before a buddy hopped on it cold as iced and revved the piss out of it. Most pistons will last you if they are installed correctly and maintained correctly.
 
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Well I ordered a namura, we will see how long it goes. If it burns up, no big deal really. Easy to redo.
 
Will do, as soon as I can get time to do it. Overtime and moving into a new house. But hopefully by next month.
 
Really?
As a KTM guy I have always looked at Wiseco as second rate.
Much more prone to cold or heat seize and noisier running due to their greater expansion factor.

I would much prefer a Wossner over a Wiseco in my KTM or Seadoo or snowmobiles over the past 40 years.
I personally see nothing great about wossner pistons and in fact wish wiseco made a la/ct 240 piston. I have seen numerous wossners with not alot of time on them wear down pretty good and the bore still perfect. Guess it depends on the application. Maybe better in a liquid cooled? I have a ton of used wossner pistons that I will make a clock out of someday. Forged pistons all the way for the win for me. Unless I have to I never run a cast piston. Cast pistons are more prone to cold seizing on the blasters cause these young padawns start it up rev it once and off they go. No time for warm up etc
 
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Well I ordered a namura, we will see how long it goes. If it burns up, no big deal really. Easy to redo.
Yes easy to redo but not when it takes out your crank, cases, etc. Chinese cylinder kit or namura, no difference same junk.
 
cast
 

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I personally see nothing great about wossner pistons and in fact wish wiseco made a la/ct 240 piston. I have seen numerous wossners with not alot of time on them wear down pretty good and the bore still perfect. Guess it depends on the application. Maybe better in a liquid cooled? I have a ton of used wossner pistons that I will make a clock out of someday. Forged pistons all the way for the win for me. Unless I have to I never run a cast piston. Cast pistons are more prone to cold seizing on the blasters cause these young padawns start it up rev it once and off they go. No time for warm up etc

Actually, you are wrong on this point. Forged pistons are absolutely more prone to cold seizing due to their greater expansion rate. This is a fact, well known and mentioned by manufacturers' and allowed for with greater initial clearance. Even the forged piston in your pictures is a cold seized piston.

The same ductility that makes the forged piston bend rather than break in the press also makes it smear if it scuffs. Cast pistons resist smearing, tend to hold oil in their crystalline structure, and resist seizing with their limited expansion. The weak intake skirt on the Blaster does make breakage a problem if you have excess clearance, but then, a forged piston doesn't solve this either.

For racing with a careful warm-up and open clearances, I would look at a forged piston. For recreational use where I want to start and run with my buddies, I run cast pistons.

I'm 40 years into running 2 strokes hard. Replaced many pistons, cast and forged. I'll agree with you that cheap pistons are problem prone, but forged pistons do come with their own set of problems. Be honest about it. Modern eutectic cast pistons last a long time. I have couple "hard-ridden" 15 year old KTM bikes with the original cast pistons in them.
 
I am not wrong on anything and understand piston differences well. Should have marked "on the blasters" in red to as I was being machine specific not piston material specific. Forged is absolutely more prone due to the material. That's why manufacturers have set tolerances. All I am saying is cast pistons have tighter tolerances and these young padawns ON BLASTERS do not like to warm them up properly and have no patience in waiting and cold seize them. Hell they can't even jet their blasters never mind order a quality piston.
 
I am not wrong on anything...

Hard to argue with a man who holds that sort of confidence! <WRY SMILE>

...and understand piston differences well. Should have marked "on the blasters" in red to as I was being machine specific not piston material specific. Forged is absolutely more prone due to the material. That's why manufacturers have set tolerances. All I am saying is cast pistons have tighter tolerances and these young padawns ON BLASTERS do not like to warm them up properly and have no patience in waiting and cold seize them. Hell they can't even jet their blasters never mind order a quality piston.

Wossner pistons are forged too, you know?
I haven't used them on the Blaster but like them on the KTM.
They seem less expansion prone and more scuff resistant than the Wiseco (in a KTM).
I don't know who makes KTM's cast pistons (Vertex?) but I ride a 125 at highway speeds on a cast piston. Excellent service and capable of speeds in excess of 85mph with present sprocketing.
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You might find this interesting, various KTM 125 pistons.
The marked number is piston weight. Wiseco Lite was lightest by far.
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A lot of the weight reduction is from the short pin.
It didn't translate into much of a noticeable effect but lighter is theoretically better.
The Namura single ring piston was in part so heavy because it used a heavy full length pin.
 
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