Namura pistons

4/12/2018 3:30pm
Has anyone actually run these in your two stroke? I can get a Namura kit for half the price of Wiseco, and I know you get what you pay for.... usually.

Are these are horrible as the price suggests? Looking to freshen up a 2007 KX250
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4/12/2018 3:43pm
Very hit or miss. Not as high quality as others. I would suggest buying ANY piston but the Namura.
Korbenw7p3c
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Central Illinois, IL US
4/12/2018 5:25pm
Yup, I just asked the same question a couple of months ago. I was told to avoid them like the plague. Vertex, OEM would be a better choice I’m told.
rmoto003
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Gulf Shores, AL US
4/12/2018 9:11pm
Depends on how much you like metal shavings. Some people like them, idk.

I dont, so I avoid Namura trash.

Namura- #1 piston choice of Bubba sellin his '85 cr250 on craigslist
godog
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CA
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4/12/2018 10:36pm
This brand definitely has a very short life span in comparison to oem. Best steer clear.

The Shop

40acres
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Tomball, TX US
4/12/2018 11:06pm Edited Date/Time 4/12/2018 11:08pm
I've ACTUALLY used them before in the past and never had a problem. I got just as much lifespan out of a Namura as any of the other postons I've used (Vertex, Wiseco, OEM). I have a couple buddies use them as well, with no problems. I now run OEM only but I also get a very nice price on them. If I was in a pinch I would have no issues running them again.
kb228
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Mansfield, OH US
4/13/2018 3:18am
Namura is absolute junk. When i was about 17 i bought one because that was what i could afford at the time & didnt know better. Was doing my first top end ever on my 125. My dad put a wiseco in it before then. When i took the old piston out and compared the two i noticed how much weaker of a design the namura was. On top of that it was a cast piston and the wiseco was forged. I decided to return it and went with wiseco. Since then i purchased a yz250. It blew up within 2 hours of owning it. Guess what piston was in it when i took it apart? The namura skirt shattered.

TLDR: go with cp, je, or wiseco.
lcgordon711
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Denver, CO US
4/13/2018 8:43am
Put one in my buddies 03 kx 250, only one we could find in the bore that we needed. He does not ride too hard, I defiantly questioned it but it has ran good for over a year now. So we will see. The mechanic I had bore out the cylinder recommended the piston to me says he had decent luck with them. How much is a top end kit really though, if you can get the size you need in another brand I feel like I would do that.
4/13/2018 1:12pm
Put one in my buddies 03 kx 250, only one we could find in the bore that we needed. He does not ride too hard, I...
Put one in my buddies 03 kx 250, only one we could find in the bore that we needed. He does not ride too hard, I defiantly questioned it but it has ran good for over a year now. So we will see. The mechanic I had bore out the cylinder recommended the piston to me says he had decent luck with them. How much is a top end kit really though, if you can get the size you need in another brand I feel like I would do that.
I believe it’s like $40 more for a Wiseco, with gaskets.

I bought a CR125 with one already installed and I ran the piss out of it for about 50 hours. Sold it to a friend for cheap, with the knowledge it has hours on it and he replaced it.

It really depends on whether or not everything else is up to spec and in fantastic condition. I would say they work okay, but they will be the weak link.

Also, a dropped skirt(hah) is more than likely from an oval bore and piston slap.
Tracktor
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The RTF/Amboy, WA US
4/13/2018 5:19pm
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems.. You think they are quality and dirt cheap?..........Throw in a Hotrods crank with it if you really want to gamble.......
40acres
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Tomball, TX US
4/13/2018 5:26pm
Tracktor wrote:
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems...
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems.. You think they are quality and dirt cheap?..........Throw in a Hotrods crank with it if you really want to gamble.......
How many hours did your Namura piston last?
Korbenw7p3c
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Central Illinois, IL US
4/13/2018 5:38pm
Tracktor wrote:
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems...
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems.. You think they are quality and dirt cheap?..........Throw in a Hotrods crank with it if you really want to gamble.......
Ha ha ha! Hot rods crank, or try a Wiseco crank too.
OP just stick an OEM in and you’re GTG.
I bought a top end kit, all OEM for $109.00 for a RM 85.
BobPA
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PA US
4/13/2018 9:07pm
Put one in my buddies 03 kx 250, only one we could find in the bore that we needed. He does not ride too hard, I...
Put one in my buddies 03 kx 250, only one we could find in the bore that we needed. He does not ride too hard, I defiantly questioned it but it has ran good for over a year now. So we will see. The mechanic I had bore out the cylinder recommended the piston to me says he had decent luck with them. How much is a top end kit really though, if you can get the size you need in another brand I feel like I would do that.
I believe it’s like $40 more for a Wiseco, with gaskets. I bought a CR125 with one already installed and I ran the piss out of...
I believe it’s like $40 more for a Wiseco, with gaskets.

I bought a CR125 with one already installed and I ran the piss out of it for about 50 hours. Sold it to a friend for cheap, with the knowledge it has hours on it and he replaced it.

It really depends on whether or not everything else is up to spec and in fantastic condition. I would say they work okay, but they will be the weak link.

Also, a dropped skirt(hah) is more than likely from an oval bore and piston slap.
50 hours on a 125 piston? You must not ride very hard...my 125 feels tired after 15
Tracktor
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The RTF/Amboy, WA US
4/18/2018 12:04pm
Tracktor wrote:
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems...
NO NO NO! Complete crap. Circlips made out of safety wire. Save $40 and spend $600. Yeah I know, judros use them everyday with no problems.. You think they are quality and dirt cheap?..........Throw in a Hotrods crank with it if you really want to gamble.......
40acres wrote:
How many hours did your Namura piston last?
Wasn't mine but a friends bike that another "mechanic" had put the piston in. Made it about 5 hours before destroying piston, cylinder, & head. Also rebuilt bottom end and crank just in case any metal had contaminated the bearings. Bike was a 16 KX85 with about 20hrs on it. Namura was first rebuild...........Not an isolated incident either as I know one time doesn't make a pattern..........
4/18/2018 12:10pm
BobPA wrote:
50 hours on a 125 piston? You must not ride very hard...my 125 feels tired after 15
I was 12 when I first got it and sold it when I was 16. Strictly for messing around in the woods and I could start it by hand when I was done with it. Good little bike though, and very resilient. Air filter and oil changes go a long way.
Matt Fisher
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Visalia, CA US
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4/18/2018 9:45pm
Your question comes up every now and then. I wouldn't put one of their pistons in a bike I was giving away. This is a clip of my personal experience:


"They sure as hell wouldn't stand behind their product when 1/8" of a circlip broke off, taking the cylinder and head with it.

From Namura:
"I was able to run this by our warranty staff. What we are willing to do is replace the piston kit. Due to the abnormal nature of this failure, this is all I am authorized to provide."

Wtf! if it was a normal failure they'd have covered the cylinder/head? There were maybe 2-3 tanks of fuel run through the motor, it wasn't some high hour deal. The rest of the circlip stayed in the piston, just about 1/8" of the clip broke off. Metallurgy issue, imo.

They can pound sand."


That's from this thread: https://www.vitalmx.com/forums/Moto-Related,20/Namura-piston,1270951?mo…
Lightning78
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Huntington Beach, CA US
4/20/2018 11:41am
I ran them HARD in one of my RM250’s and never had a problem with them.... broke the skirt off an oem and pro-x though in the same bike
4/20/2018 12:11pm
I ran them HARD in one of my RM250’s and never had a problem with them.... broke the skirt off an oem and pro-x though in...
I ran them HARD in one of my RM250’s and never had a problem with them.... broke the skirt off an oem and pro-x though in the same bike
That can be an issue with cast pistons if the bore isn’t completely straight/not oval. Forged pistons can take more abuse.

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