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HELP! installing a Wiseco piston and need immediate help...

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I am installing a big bore Wiseco piston in a XR400 and need confirmation on direction of arrow on top of piston.

Does arrow point toward intake valve (rear of bike). Stock piston is marked "in" for intake side. Wiseco is marked with arrow. If arrow points to intakes side the part numbers are right reading from rear of bike. Anyone know the correct answer?

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What would happen if you install it with the arrow facing the intake? I put my 280 together about a month ago and I put the wiseco piston in with the arrow facing the intake. I could have sworn I read on this site thats how it went in. Anyway, I have'nt had any problems. Should I take it apart and change it? Man, I'm kind of freaked out! :cry:

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I can't speak for the 250, but my 400 has 2 different valve sizes. If i were to install mine backwards i am sure that the piston would contact the valves. I know its a PITA, but I would install it the right way, that way it doenst break down on you out on the trail.

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In my opinion, the valve cut-outs are the reason for the aarow. He is most likely fine since there is clearence and it runs fine.

I wouldn't tear it down. You'll know better when you go to do the 300cc kit in a few years :cry:.

Still worried.....call wiseco tech and get their opinion.

They are a great company we are proud to have in Ohio.

Technical Assistance -1-440-951-6600

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I was just installing my Wiseco (416) last night and to clarify:

The stock piston has "IN" stamped on it which should be towards the intake side of the cylinder or the rear of the bike.

The Wiseco piston has an "->" stamped on it which should point towards the exhaust side of the cylinder or the front of the bike.

Keanu, have you had any problems with the 280 installed backwards?

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I am installing a big bore Wiseco piston in a XR400 and need confirmation on direction of arrow on top of piston.

Does arrow point toward intake valve (rear of bike). Stock piston is marked "in" for intake side. Wiseco is marked with arrow. If arrow points to intakes side the part numbers are right reading from rear of bike. Anyone know the correct answer?

seems like wiseco only and always marks their pistons to indicate the exhaust side.

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What would happen if you install it with the arrow facing the intake? I put my 280 together about a month ago and I put the wiseco piston in with the arrow facing the intake. I could have sworn I read on this site thats how it went in. Anyway, I have'nt had any problems. Should I take it apart and change it? Man, I'm kind of freaked out! :)

great scott! this could cause a tear in the very fabric of the space time continuim!

but seriously, this sounds like something you should investigate!

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Hahaha! Is that a Back to the Future Quote? I think it is.

Yes it would be wise to contact wiseco about this delema!

They'll probly say, "Oh you dumb Barsted, Why would we put an arrow on the ****ing piston for it to face backwards hey!?"

Well mabey not that harsh, but see what they say.

I thought mabe Gudgeon Pin is off set? But that couldnt be the case id its running fine.

Mabey if you rev its guts out the valves will hit the piston! Give it go go! See what happens! :)

Oh well Good luck and have fun! :)

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Gudgeon Pin ??????????????..........Speak English.....LOL

Good Day A

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Hahaha! Is that a Back to the Future Quote? I think it is.

Yes it would be wise to contact wiseco about this delema!

They'll probly say, "Oh you dumb Barsted, Why would we put an arrow on the ****ing piston for it to face backwards hey!?"

Well mabey not that harsh, but see what they say.

I thought mabe Gudgeon Pin is off set? But that couldnt be the case id its running fine.

Mabey if you rev its guts out the valves will hit the piston! Give it go go! See what happens! :)

Oh well Good luck and have fun! :)

I have called Wiseco before and they were very helpful. I measured the valve reliefs on my Wiseco piston and they were all the same. The only other thing could be the offset pin. On car motors the pin is offset.

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Well Dale, thats very interesting!

Bit of a mistery isnt it!

What did they say will happen and recomend if you do put the piston is backwards?

HEY johnnyutah!

What did you end up doing about your backwards wiseco piston??? Did you rip into it and turn it around? Or is it still running fine?

Originally Posted by L354

Gudgeon Pin ??????????????..........Speak English.....LOL

Good Day A

Dont youse call the "Piston pin", a Gudgeon Pin in Michigan? :)

That is what its called.

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