Quick question

[Zbskater400]

Hey guys. I just wanted to know about a bigger piston I got a numura piston kit which is 67:42 mm over. Bigger than stock now I know I have to bore and hone my cylinder and
I know most about blasters and engines but what exactly would does a bigger piston do than stock? Like faster ? Or what ? I've always wasted to know. Now I'm not an engine builder and I don't know everything about pistons and stuff like that and I'm not afraid to say it ahah hopefully someone Can teach me what it does to put a bigger piston in thank you guys!

 

[Blaaster]

Putting in a larger piston increases the capacity of the engine, which in turn will increase power.

Increasing the piston from 66 to 67.42 will add only 1 or 2 Ccs which result in a very, very small increase in power.

There is no need to change the jetting for such a small increase in piston size.

A stock Blaster bore will allow a displacement of 195 Ccs, if you go for a Big Bore kit it will increase the Ccs to 240.

 

[BmxnBlasters]

What made you choose namura for a piston?

 

[best]

What made you choose namura for a piston?

Likely price!
I've used them in my KTM and like them fine.

Oversize piston only increase displacement negligibly.
Do the math: A 2% increase in diameter is a 4% increase in area.
4% hp increase brings us from 17hp to 17.68 hp.

Steve

 

[BmxnBlasters]

I have always had bad luck with them in powervalve motors i have used them in. I dont cheap out on engine parts. Not worth the risk

 

[Larry's Shee]

Hey guys. I just wanted to know about a bigger piston I got a numura piston kit which is 67:42 mm over. Bigger than stock now I know I have to bore and hone my cylinder and
I know most about blasters and engines but what exactly would does a bigger piston do than stock? Like faster ? Or what ? I've always wasted to know. Now I'm not an engine builder and I don't know everything about pistons and stuff like that and I'm not afraid to say it ahah hopefully someone Can teach me what it does to put a bigger piston in thank you guys!

You only bore enough to "freshen" up an engine. Do not waste bore sizes just because you have that piston.

 

[best]

I have always had bad luck with them in powervalve motors i have used them in. I dont cheap out on engine parts. Not worth the risk

I have had problems with Wiseco. Must be carefully warmed or will 4-square seize.

My KTM is a powervalve engine. No problems. What sort of problems have you had with Namura?

Steve

 

[240Fun]

I think the only reason people believe over bore pistons add power is more due to the fact that they more than likely have been losing compression over time and not noticed the slow power loss

 

[joeak47]

I have ran Namura, wsm, ART (stock) , and vertex with ZERO problems. Yes they are all cast pistons, and yes they work great. Wiseco's are good too as long as you warm up your ride properly BEFORE riding. I prefer cast pistons.

 

[Blaaster]

Recently I posted a pic of a stock cast piston taken from my 2005 Blaster with countless hours of hard work on it.

There was very little wear apparent and the skirt had the tooling marks very visible.

I replaced it with a Forged piston because that was what Ken supplied, I would have been more than happy if he had supplied me with a cast one, as cast has served me well.

Time now to learn how to warm up a forged piston.

 

[Zbskater400]

I bought the 67:42 Namura cast piston because it was Cheap and so I had it when my bike craps the bed so I can just put that in and won't have to worry about not having money for a new top end

 

[Blaaster]

Do a compression test and if it is low put that piston in before it craps itself.

 

[Awk08]

Time now to learn how to warm up a forged piston.

not much to learn, start the bike allowing it to idle for the 3-4 minutes it takes to put your gear on, hop on turning choke off and blip the throttle a few times within the minute or so until you can barely hold your hand on the cylinder.
total time, less than 4-5 minutes

i did the same warmup for 8+ years with my totally stock 96
unsure why anyone would run anything without warming it up ?

 

[Blaaster]

Have always warmed up every engine I have ridden,90% of engine wear happens in the 30 seconds after startup.

My statement was mainly tongue in cheek, as forged pistons need a more precise warm up. And believe it or not this if my first ever one, I have always used cast.

We are blessed in my part of the country, with high temps and the engine needs very little choke, and about 2 mins to get to riding temp.