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wiesco std piston arrow direction.

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Just Put in new wiesco piston kit and put it in with the small arrow on top pointing toward the intake side is this right? I rode it and it seems to run ok. Any answers will be greatly appreciated.

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uhh, for real? i'm pretty sure that arrow means to be pointing toward the front of the bike

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arrow always points towards the exhaust.

Are you sure you put it in that way? seems like you would have some valve clearance issues... One thing I look at on the 4 stoke pistons is the intake side always has the bigger cut outs for the valves.

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pretty sure it was put toward the intake side. Hope it did not bend my valves

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One thing I look at on the 4 stoke pistons is the intake side always has the bigger cut outs for the [bigger intake] valves.
Exactly. :)

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i just did my 07 with a wiseco and i believe the instructions said to put the arrow towards the intake.i somewhat remember that because as someone else said the arrow would go towards the exhaust and that had me confused because i think i used to put my old 2 strokes together that way.i put the old piston back in the box but i think i threw the directions away,ill take a look.a quick call to wiseco would clear everything up though.:)

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I hope I can just install new ones. I only ran bike for like 5 min. If I have to have seats cut what will this consist of parts wise. I found directions and looked them over and arrow is to be toward exhaust. Friend of mine use to do alot of 2 stroke pistons also and he said to put it toward the intake.

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Goin toward the intake makes no sense.. the arrow is the direction of flow...................................................

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did u take it out yet?? theres only one real way to find out.

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This is from my old 250, but it´s a standard comp Wiseco.

The arrow points in the direction of gas flow:

IMG_1099-1.jpg

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well,i must have installed it right because i have already raced it and havent had any issues,maybe it was one of the gaskets that had me thinking.hope you get it all sorted out without any trouble.

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If it was in the wrong way, I'm thinking you would have bent all your valves as soon as you kicked it over, and so it would never have started. The cut outs in the crown for the inlets are larger and also nearer to the center. Your printed instructions are of course right. If you did it wrong I'm really surprised it ran. Surely an engine that pumps it out like these babies have the valves getting awfully close to the piston. Maybe you have marks on the piston from the valves touching, and the valves flexed enough to not get damaged. If things are not damaged I'm shocked. fyi. The valves in my 150cc Lifan pitbike have about 0.5mm piston clearance so no way can that little piston go in the wrong way.

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I am pretty sure it is in backwards. The weird thing is it will start on 2nd kick everytime. Also do you think it would have bent the exhaust valves since if backwards it would have put the larger cutout on the piston on the smaller exhaust valves? Anyone have and idea at what I am looking at cost wise to have new inserts and valves put in? If it marked the piston do you think I will have to put new one in or do you think this one will be ok? Thanks for the advice so far!!!!!!

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The bike wouldnt run if you put the piston in backwards, youd kick it it would stop and youd probably hear a snap. (your valves breaking) its in right, or the bike wouldnt start.

The bike is fine.

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Thanks for the help guys. I remember now that the arrow was pointing toward the exhaust but it was located on the intake side of the piston. I guess I got confused when I heard point toward the exhaust side and thought I should have turned piston 180 and had arrow on exhaust side of piston but that would have put arrow pointing toward intake then. But I still have the issue of backfire on decel?

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Thanks for the help guys. I remember now that the arrow was pointing toward the exhaust but it was located on the intake side of the piston. I guess I got confused when I heard point toward the exhaust side and thought I should have turned piston 180 and had arrow on exhaust side of piston but that would have put arrow pointing toward intake then. But I still have the issue of backfire on decel?

backfire on decel is normal. mine has a complete rebuild and has only 30 minutes. it pops a couple times from high rpm to deceleration.

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Thanks for the help guys. I remember now that the arrow was pointing toward the exhaust but it was located on the intake side of the piston. I guess I got confused when I heard point toward the exhaust side and thought I should have turned piston 180 and had arrow on exhaust side of piston but that would have put arrow pointing toward intake then. But I still have the issue of backfire on decel?

haha man you're lucky

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I was told the arrow should point towards the front of the bike which is weird because the arrows stamped at the intake side of the piston. What's up Wiseco? I think that if you rotate by hand and the piston doesn't hit a valve, your probally good to go.

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The arrow should definately point toward the exhuast, Fresh engines tend to pop a little more on decel it will get better as it loosens up but will never disapear

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