What piston, Wiseco, Pro-x, Namura, WSM

[deeeebeeeeee]

Seems like their are tons of piston makers and types. Cast or forged, Round or flat dome, moly coated, different shape and sizes of holes in the skirt to match intake ports, etc, etc.

I plan to send my stuff to Ken for boring and head rechamber, will probably go either .020 or .040 over, as I want to bore out someone's homespun intake port window chamfer. (Shape and height were left alone)

Performance is a concern, but my BIGGEST concern is longevity, followed by cost.
Shooting for low 20's for Horsepower WITH: 28mm Mikuni carb, Pro Circuit pipe, head rechamber, slight overbore, mild port work, and Boyesen power reeds on stock cage. Does this sound reasonable?

I want a quality piece without breaking the bank.
I don't have a problem with the warm up time required for a forged piston.
I have heard that the lightened wiseco's are good but can break at the skirt if you put too many hours on them?

I plan to replace the crank seals while I am at it, but will not split the cases unless I must.

What brand piston should I go with?
Actually I will need a top end kit, as it seems to be preferable to/ a little less expensive than buying seperate.
Any reccomendations for a top end kit, gaskets etc.

 

[MURPH]

I would recommend using the oem Yamaha cylinder and boring it out. those whole top end kits with those chinese cylinders are junk. you will get a million different opinions on what the best piston brand is but I have used wiseco, namara, and wsm pistons in various 2 stroke motors and had good results

 

[jvb]

I'm using a Wiseco pro lite forged piston, indeed you need to let warm up a bit but because a blaster has a steel sleeve you should do that anyways!
I put 40 hours on a piston before i replace it.
Forged pistons are harder on the cylinder wall, a normal piston is alot 'softer'
Forged pistons can handle alot more stress.
I have nothing but good experiences with Wiseco!
And Yamaha o.e.m gaskets.

 

[deeeebeeeeee]

I would recommend using the oem Yamaha cylinder and boring it out. those whole top end kits with those chinese cylinders are junk. you will get a million different opinions on what the best piston brand is but I have used wiseco, namara, and wsm pistons in various 2 stroke motors and had good results

Yeah I know about those Chinese cylinders, I already got a factory cylinder and head set, looks like someone did their own intake and transfer port chamfer with a 36 grit stone. It's literally that rough no wonder the piston ceased.
Fortunately they didn't go very deep with it i imagine .040 over will get rid of the most of it.

If it wasn't for that i could port and hone the cylinder and just drop it over top the factory piston with a new set of rings. Just to do testing after each change. That would probably get expensive quick as far as gaskets go.

At first I am going to send the head off to Ken for a rechamber and just pop it on top of what I already got.
Then I am going to get my piston and top end kit together and send it all off to Ken for a bore job.
I could be wrong be I am afraid the big end rod bearing might be out of spec when I get the top off. So I want to have the top paid for and ready to go before rebuild time. Then if I gotta split the cases......

 

[Blaaster]

I'm using a Wiseco pro lite forged piston, indeed you need to let warm up a bit but because a blaster has a steel sleeve you should do that anyways!
I put 40 hours on a piston before i replace it.
Forged pistons are harder on the cylinder wall, a normal piston is alot 'softer'
Forged pistons can handle alot more stress.
I have nothing but good experiences with Wiseco!
And Yamaha o.e.m gaskets.

Mmmmm, I have trouble digesting that a forged piston is harder on the cylinder wall then a normal one.

If adequate lubrication with an oil of a great film strength is supplied then a piston should never contact the cylinder wall.

Forged Pistons do have an advantage in that they are less prone to deteriation from heat caused by detonation.

 

[OConnor Racing]

I use cast pistons (OEM) in all of the dirt bike engines that I build for the simple reason that they're much lighter. I've used cast pistons in Blasters but I would rather run a forged piston it them. The biggest reason I like the Wiseco is because you guys run the sh*t out of these quads and expect them to last for 200 + hours. The motocross guys are doing top ends three times a year. If a cast piston breaks, it's always in small pieces that get into your cases between the crank and the case. 80% of the time this leads to cracked cases. A forged piston will crack when it's had enough and start slapping.

 

[jvb]

Mmmmm, I have trouble digesting that a forged piston is harder on the cylinder wall then a normal one.

If adequate lubrication with an oil of a great film strength is supplied then a piston should never contact the cylinder wall.

A forged piston expands more , therefore when the engine is cold you could have some piston slap due to a too small piston.
That's how i understand it Blaaster, but i'm always eager to learn so anyone has some input on this?

 

[Blaaster]

A forged piston expands at an irregular rate, the more solid parts around the wrist pin expand at a greater rate than then surrounding thinner parts.

That is the reason that you need to fully heat up a forged piston before riding.

Cast pistons are more forgiving as they warm up a little more evenly due to the cast structure.

 

[deeeebeeeeee]

I use cast pistons (OEM) in all of the dirt bike engines that I build for the simple reason that they're much lighter. I've used cast pistons in Blasters but I would rather run a forged piston it them. The biggest reason I like the Wiseco is because you guys run the sh*t out of these quads and expect them to last for 200 + hours. The motocross guys are doing top ends three times a year. If a cast piston breaks, it's always in small pieces that get into your cases between the crank and the case. 80% of the time this leads to cracked cases. A forged piston will crack when it's had enough and start slapping.

Looks like it's going to be a forged Wiseco for me, hello Pro-Lite.

 

[joeak47]

20 hp huh? Why not use the porting templates, match the transfer ports to the case, and see 30+ RELIABLE HP, all while using the STOCK CARB that actually fits the manifold and air boot.

What I'm saying is... PURCHASE THE PORTING TEMPLATES!!!

YOU CAN THANK ME LATER.

 

[joeak47]

Look at it this way... you can always sell the templates when your done using them and recoup most of your money back. Think about it. Using a proven template that works VS guessing what MIGHT work.

 

[deeeebeeeeee]

The 28mm miKuni will fit the boot, be it a little tight. I got it for much less than the cost of a tors delete and can adjust my idle on the fly without removing the seat. It is really a minor change. takes more airflow to get the needle and main jet kicking, allows a little more maximum airflow, with a little more accurate metering at that higher flow. If it isn't too large for a KX 80, I don't think a 200 will loose anything using it versus a Stock
26mm unit with TORS. Not really that much bigger but Not spending $100 for a boot and $300 for a carb.

I have stated my objective is to learn and I still don't know what you expect I will learn from using a pre-made template.
Low mid 20's is a conservative number, it is my first try if power is made at or above that level then, i will consider it a success. Since i am trying to learn something that is as much an art and a skill as it is a science. I will be happy with a 33% increase over stock putting it at 23.2 horse.

Port Timing specs, port areas, and software calculators/ simulators are available on the net for free, as well as various port maps for the blaster itself. It's just not sporting (pun intended) to straight copy someone else's work, sure it will make pretty much guarenteed Horsepower ( supposing I do it right), but I learn nothing except how to operate a rotary tool precisely. I really can't see paying more than a few dollars for a piece of heavy card stock, no matter how valuable the information it contains may be.

To me It is like , I could pay $1100 for a guided elk hunt and unless I just screw up I am guarenteed a nice elk, or I could pay a tenth of that for a license and some shells, and with enough know how and by studying the land map, go out on state or national forest, hunt and stalk a bull elk of my own, No guarenteed kill, even if I do well and make a kill it may not be a trophy. But it is something I accomplished making each choice by myself. It is simply a way of testing and demonstrating, my recently acquired knowledge and skill, should I fail then, I have misjudged the value of some of the information I received, overlooked some thing big, or simply screwed up. Not the end of the world.


For less than the cost of the sport port templates, and associated tools, i could just have Ken do the work himself.
Can't see why i would spend more to make a lower quality partial copy of His work, than it would cost to have all of his knowledge and skill applied to a higher quality and guarenteed product.

I get the value of the sport port templates, I also understand it is only gives you the outline and positioning of the port windows, it would still take a reasonable amount of knowledge to get the rest of the port right. It just feels like cheating to me. Unless the template came with an hour session with Ken himself to explain why each component of the template is the way it is and the effects of any possible modifications, with a few minutes left over to pick his brain, then it would be educational and we'll more valuable, than the asking price.

If all I wanted was a 30 hp Blaster, then I would have saved myself hours of reading, as well as the additional hours of studying, and working over a hunk of metal w/ powdered aluminum flying through the air, and just cough up a few hundred dollars and have it done.

Many, find pride in the material things they have, some find pride in what they can create with their hands, only a few find pride in what they are able to create with their minds. One is no better than the other, but I am one of those that only really feel accomplished when I have used my mind and my hand to create something. It's not too glorious of a thing, someone asks you how you did this or that it's so much easier and interesting to name a product, and speak of its benefits. Than it is to go off into a 20 minute dry lecture about the finer details of your work and why you did this or that.

Yeah I am weird like that, can't help it

Deebee