Namura Pistons

[cheezehead]

What are these pistons like compared to Wiseco?

[frocashmoney24]

ive heard allital about them but not much, for how much they cost i would stick to weisco cause there a much more reputable company

[sinkorswim]

i have been running them for awhile. I did have in vitoes then bored it out to freshen it up. They are a cast piston that is the same as stock but shorter and have bigger intake skirt holes. They seem to be a good piston but might not take the revs like the wiseco. the price is cheaper because they are cast and not forged.

Adam

[thecabinboy]

stick with whats provin' to work

[cgamla]

I have a set in mine and they seem to be just fine. They were lighter than the stock pistons and seem to be pretty good quality. The price is right on ebay thats for sure. I have revved mine to the moon and never had a problem. I liked the idea of cast pistons because I heard that forged required a good warm up time. I can't sit in my yard with my shee idiling for 10 minutes because my neighbors would go nuts. I need to start it up and go away instantly.

[reas11]

I have a set in mine and they seem to be just fine. They were lighter than the stock pistons and seem to be pretty good quality. The price is right on ebay thats for sure. I have revved mine to the moon and never had a problem. I liked the idea of cast pistons because I heard that forged required a good warm up time. I can't sit in  my yard with my shee idiling for 10 minutes because my neighbors would go nuts. I need to start it up and go away instantly.

thats not really a good thing u should let the bike warm up properly no matter what pistons u are using to ensure longer engine life.if u fail to warm it up the pistons will scar the sides of your jugs .

[Meat]

iv heard of clearance problems with the namura piston's raised domes when using an aftermarket head. Any of you namura guys running billet heads ???

[Nighty]

I heared the namura make 6 extra HP over stock.

 

The wiseco's dont make extra horses do they?

and the wiseco's are a bit heavier over the stock ones to which would result in slower reving?

[boonman]

The Wiseco's are heavier because there is more material packed in there. A forged product is 99% of the time better than a caat product. It's material physical properties that we're talking about here. Namua pistons do not out of the box add 6 ponies. However, Vito's pistons are slated to give you 6 more HP on the chart. Vito's pistons are Wiseco. Wiseco is the better piston here. The reason for the warmup is that a forged piston does not expand at the same rate the sleeve does when warming the engine up. The piston expands faster than the sleeve. So, if you kick it and rip it, (fire it up, and go haulin ass down the trail) you will cold sieze the engine. Happens hen the piston expands too fast, and it tightens up the tolerance in the bore, and it galls to the cylinder wall. This is bad. Now, that is the ONLY drawback with a forged piston. With a cast piston, you can kick and rip, BUT, they are also more prone to cracking a skirt off, and general piston failure. It is an undeniable fact. Cast things are porous. Forged, usually aren't. IMHO, anyone who doesn't let the bike warm up even a little bit is just asking for problems..........

[sinkorswim]

http://www.motorcycleproject.com/motorcycl...ws-pistons.html

http://www.mxbikes.com/tech/article.php?TID=4

 

check out this web page. It amounts to what you are using it for.

[YB350]

We just bought some Namura pistons so all of this is good to hear but we are going ahead with the rebuild anyways , one question does any one know the piston skirt clearance , that info did not come with the pistons and they are going in for the rebore this monday . we have a 1996 banshee and the pistons are 66mm....thanx

Edited July 10, 2005 by YB350

[80overShee]

The Wiseco's are heavier because there is more material packed in there.  A forged product is 99% of the time better than a caat product.  It's material physical properties that we're talking about here.  Namua pistons do not out of the box add 6 ponies.  However, Vito's pistons are slated to give you 6 more HP on the chart.  Vito's pistons are Wiseco.  Wiseco is the better piston here.  The reason for the warmup is that a forged piston does not expand at the same rate the sleeve does when warming the engine up.  The piston expands faster than the sleeve.  So, if you kick it and rip it, (fire it up, and go haulin ass down the trail) you will cold sieze the engine.  Happens hen the piston expands too fast, and it tightens up the tolerance in the bore, and it galls to the cylinder wall.  This is bad.  Now, that is the ONLY drawback with a forged piston.  With a cast piston, you can kick and rip, BUT, they are also more prone to cracking a skirt off, and general piston failure.  It is an undeniable fact.  Cast things are porous.  Forged, usually aren't.  IMHO, anyone who doesn't let the bike warm up even a little bit is just asking for problems.......... 

192674[/snapback]

 

WORD Vitos pistons are Wiseco with the intake ports enlarged to match the ports in the cylinder

[Nightrider]

iv heard of clearance problems with the namura piston's raised domes when using an aftermarket head. Any of you namura guys running billet heads ???

192522[/snapback]

 

I heard that too.I currently run Namuras in one of my shees,but I'm running a stock head.With some light porting,the compression turned out to be 125psi on standard bore,It would have probably been around 140 without portwork.I run .0025-.0029 clearance on the bores.I would not recommend them for over 145Psi.The crown is very thin.

 

The midrange punch this engine has with Fatties, v-force and lightened flywheel is sick.Climbs hills like a 4stroke.

[YB350]

Nightrider so you are running .0025 -.0029 piston skirt clearance ? do you know if that is what the factory recommends ??

Edited July 10, 2005 by YB350

[Nightrider]

Nightrider so you are running .0025 -.0029 piston skirt clearance ? do you know if that is what the factory recommends ??

390697[/snapback]

 

The manuel specs for stock pistons is .002-.0025.With any cast piston,you do not want to exceed about .003.Cast pistons have a experience minimal expansion.Any more than .003-.0035 and your pistons will wear out rapidly.