Are these stock?

[n2otoofast4u]

Working out of town leaves me just 2 days every couple weeks to work on my sled and thus far everytime has been to discover more issues. So today I was asked "does it have stock pistons" and much to my dislike I had to answer IDK... So I had the wife snap these pics for me. Im not there to answer much more than this can show so any help is appreciated. Also, the valve springs are painted purple on the tops. Does this mean anything (stock or aftermarket) Any good way of telling if the retainers are stock or aftermarket? I bought the sled used and everything that it was supposed to be it hasnt been so I cant go off of what I was told.. Thanks in advance.

 

[Longhorse]

I assume this is a Nytro motor? or is it an Apex?

 

[n2otoofast4u]

I appologize, yes its a nytro.

 

[BigFish BC]

pretty sure there stock low comp ones are dished those look flat.low comp ones
http://www.terraalpsracing.com/product/yamaha-nytro-3-cyl

 

[apex jeff]

One thing for sure, that head has been off looking at the copperkote gasket spray.

 

[Longhorse]

Yours look dished out just like the JE's in the picture of the previous post just not as clean. I never saw the JE's that went in my sled so I can't confirm that. By the looks of the head gasket it's certainly been taken off before. I'm guessing that those are not stock pistons.


These are the stock parts out of my 08 Nytro. There's a dimple on the top edge of the exhaust side and a slightly raised "umbilicus" right in the center of each piston. Valve springs have red paint on the top coil.

 

[n2otoofast4u]

Man thank you so much!!! I also did some more digging when I got back to the hotel tonight and I think you are spot on. The pistons in my motor do not look like the picture of what I think is a stock one and your post confirms my thought. I wonder if I could take a measurment from top of piston to bottom of dish and have JE (assuming thats what they are) tell me what ratio they are. Im going home thursday so I can see me burning up the phone lines on friday. My valve springs are deffinately purple on the top not red so Ill have to start trying to figure out what they are as well.. Thank you again for your reply.

This is what I believe stock to be.

 

[Longhorse]

Mine was built by Dustin at Out Law Motorsports in Oregon. They had JE run a special batch of 10:1 pistons for a few of us who didn't want to loose any low end torque and were ok paying for good fuel ALL the time. However, I was told that after that initial special order run they started putting 9.5:1's in everything so they could advertise "pump fuel turbos" to appeal to the economic side of folks, then the head shim was an even more economic solution for guys that didn't care to beef up their pistons or rods.

 

[Tarzannr1]

That engine also have Arp studs on it.
Wonder if there also is carrillo rods on it to.
And the pistons can also be CP-pistons.

 

[Tarzannr1]

And do the pistons have marks after detonations on them?

 

[n2otoofast4u]

Yeah, I was told it had studs and it does infact have them. Im also curious about rods. Im wondering if I pull the pan off the bottom will it open things up enough to see the rods, and maybe with a scope the bottom of the pistons to verify a part#?

 

[n2otoofast4u]

So I got home today and was able to take the oil pan off and to my suprise I was able to see the PN on the pistons which is 274211 which I have found to be a 9.5cr JE piston, and it also has carrilo rods in it. So Im learning about what is in the bottom so not to the top. I took a good look at the color of the paint on the valve springs and it appears to actually be a faded red, not a purple like I once thought and the rest of the parts appear to be stock as well. However the intake side of the head looks way to nice to be as cast from Yamaha so I snapped a few pics and would like to hear some insite from other as to if this appears stock or not as well...

Intake

Exhaust

 

[Tarzannr1]

Yes the intake is ported but the exhaust looks stock.
Looks like that engine is used some money on, what about the cams (cam shafts) are they stock ore race-cams?