What Piston?

[GrounD PoundeR]

I am wanting to put a 440 kit and I am hoping that you guys might be able to help me out with a piston question?

What is a good piston.....Ross, JE........

I've heard to different thing about using a lighter piston and am wanting to know if they are true about loosing torque?


Finally what if any parts should be upgraded internally for a 440 running at 11:1 to 12:1?

I plan on adding a TC Cam as well.

[Dune Surfer]

I had a JE and now I run a ross. The ross is lighter and revs faster.

[anywhereEx]

I put a Ross in mine and definitly like it. It is light as anything to...

[Steven]

I run the Ross 89mm (435cc's) 11.2:1 and its very nice. The bike rips. It revs out much faster than my other 400ex which is stock except for a slip on and jet kit.

I had the wiseco 440 first and was not impressed. It was advertised as 11:1 and worked out to 9.6:1.

I wouldn't go more than 11.5:1. You are just adding alot more heat for minimal returns.

I run the 11.5:1 and have no internal problems. All I did was tap the cylinder studs deeper. The head gasket is holing the compression fine.

Anyway... Ross all the way. Its a good piston.

[GrounD PoundeR]

Thanks for the info.

[UglyMotha™]

hey dune surfer i think your piston is in bacwards i'm pretty sure the arrow is suppose to point towards the exhaust valves isn't it:confused:

[YZROOSTINYA]

LOOK AT THE VALVE POCKETS, THE INTAKES ARE SUPPOSED TO BE LARGER NOT SMALLER, it is backwards:eek:

[RiPPiNiTuP7]

Woops :eek:

[UglyMotha™]

Originally posted by YZROOSTINYA
LOOK AT THE VALVE POCKETS, THE INTAKES ARE SUPPOSED TO BE LARGER NOT SMALLER, it is backwards:eek:


That's what i thought but then again maybe it's some kind of power secret, so how's she running:huh

[YZROOSTINYA]

looks like someboys got a......




****dick...............

[sparks400ex101]

yes tell us , why is it backwards????:tired:

[Castor-426ex]

oops

[lilpoppy]

I'm gonna be doing myne for the first time soon so can you guys explain how you know it is backwards so I don't make the same mistake? I assume the piston can only be turned at a 180 so the arrow should be facing the opposit direction right? Do the pistons come with directions or does the manual explain it?

[UglyMotha™]

service manual will explain it atleast it did in mine and yes the arrow is supposed to point towards the front of the quad pretty much a no brainer

[UglyMotha™]

here is a correctly installed piston

[Dune Surfer]

You guys are sharp. I did install it backwards untill I realized my mistake:devil

[Steven]

did you run it like that?????????

WOW, good katch guys!

[Castor-426ex]

sad to say i did the same and ran it...nowhere on Je's instructions did it say so i went with the marks on the stock piston...well the valves did hit...but only slightly...very slightly...valves unhurt...and the piston isnt really damaged at all
I turned her around...put her back together...

Lets just say it doesnt smoke...runs good...but I wonder what lies in store down the road? Ill probably order another piston/rings...not sure...I did notice some lines in my cylinder i couldnt feel them...but i could see them...is this normal?i oiled the cylinder very well...thnx

[YZROOSTINYA]

you can tell by the vlave pockets besides the arrow. intake valves are larger thasn exhaust

[Castor-426ex]

its ok now:D

[2fastandfurious]

Ross is a good way to go.

[Jay300ex]

Hehe Yea that would have been an oops. The exhaust valves are smaller usually b/c it uses the engine compression to push the xhaust gases out and takes more effort to suck intake mixtures in so a bigger intake valve just makes more sense right :)


Jay