PDA

View Full Version : Directional arrows on pistons, which way?



leevarnado
03-18-2009, 05:31 PM
which way does the arrow go on a wiseco 65.5 piston,is it the pointing to the exhaust or intake.i have it the the exhaust right now.just want to know if i have it in correctly.

rdlsz24
03-18-2009, 05:37 PM
This has been a popular question lately. Points to exhaust.

Rob

Billy Golightly
03-18-2009, 05:40 PM
This has been a popular question lately. Points to exhaust.

Rob

Indeed, it has been lately. I think I'll move it to the WCH forum just as a frequently asked question.

And yes, you are correct. Arrow towards the exhaust!

leevarnado
03-18-2009, 10:01 PM
i didnt submit this tread,was going to but i close out of it.but yeah it points to the exhaust.i called wiseco and asked them.its to the exhaust.thanks any way guys

atv innovations
12-18-2009, 07:05 PM
Exhaust always and letters or any markings on the rings go up.

Nick_R_23
02-10-2010, 11:39 PM
Easiest way to remember is it points with direction of flow.

-Nick :TrikesOwn

adcotton
07-22-2012, 09:04 PM
Regaurdless of what the arrow says, the side with holes or a cut out in the skirt always goes towards the intake. I have heard of a backwards arrow, never seen one myself though.

yaegerb
07-22-2012, 10:11 PM
arrow points to exhaust port.

Flyingw
07-22-2012, 10:45 PM
Actually, the easies way to remember how the R piston goes is to remember the pins that are in the ring grooves (pins the rings close against) always always always go toward the intake. If those pins are on the exh side, the pins will catch the exh port wall everytime and tear up the cylinder. Pins to the rear everytime regardless of where the arrow points.

adcotton
07-23-2012, 01:13 AM
Actually, the easies way to remember how the R piston goes is to remember the pins that are in the ring grooves (pins the rings close against) always always always go toward the intake. If those pins are on the exh side, the pins will catch the exh port wall everytime and tear up the cylinder. Pins to the rear everytime regardless of where the arrow points.

Thats another good point!!! Not just to the R though, That goes for ALL two strokes!

Flyingw
07-23-2012, 01:27 AM
Thats afirm AD. Those pins are positioned away from the intake port whereas on the exh, they intersect the port and catch the port. Seen this many times. I learned this when I was young. I had a TM125. Fresh bore, new piston and dummy me put the piston in backards. It ran for about 20 seconds before it destroyed the bore and piston. I took it to the shop and the guy explained it to me. He laughed at me too so I wrote that down in my little book of things to never do again.