350x piston installation?

[dizasterzrfun69]

Hey guys i was looking for a new piston for my 350x and i ended up getting a whole top end with a new piston in it so i dont have any paper work to help me out. The piston has an arrow on the top but i have no idea if that arrow is supposed to point towards the exhaust or the intake. I can probablly figure out the rings but the piston itself is confusing me. thanks



Kevin

[Dirtcrasher]

Every piston I've ever seen with an arrow points towards the exhaust.

[dizasterzrfun69]

Yeah he is right. The arrow usually points to the exhaust. Or there will be a IN mark on top of the piston. There are four valve pockets on the top of a 350x piston. The two bigger valves on a 350x are the intake valves. So the piston would have to sit with the bigger pockets on the piston towrds the intake side. Just check under your head to see which valves are bigger and then you will see which side the pockets on the piston have to be on with the piston position. If you are worried about forgetting after you build it, just come back and ask and we will say, "Hey dude, you did it right remember?"

Another thing is you mentioned the piston had an arrow. That usually means its aftermarket. Usally a cast piston or honda piston would say IN on the top. Is it a Wiseco piston? If you are stuffing a foreged piston in a stock bore, you will have to have the clearence checked. Because the forged piston metal expands with heat and you need .003 clearence instead of the stock .002 and a 1/2.

That means you need more clearence with a forged piston. Just seat the rings right and jet it, it will rock.

its actually a trx350 jug and the piston was in it when i got it. heres the link http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=300101262381 i'm not sure of the clearance but it seems tight. I'll check it before i put it all together.

[dizasterzrfun69]

my book shows this

cylinder to piston clearance- Standard .015-.045mm (.0006-.0018 in) service limit .10mm (.004 in)

i tried a .003 in. feeler guage and it fits in one spot and not another. I have to put it on the side of the piston and push it in at once. according to my book that feeler guage is a little bit too big.

[Dirtcrasher]

Good score on the auction bro, barely get a piston for that price.....