OEM or Aftermarket Piston?

bucfan11 · 10-22-2009, 07:01 PM

Tore my son's 06 RM250 head off and there is a chip out of the front of the piston. I was amazed at how clean everything was...looked almost new. There is no scarring on the cylinder. I hope the chip blew out the exhaust. Aftermarket offers a two ring piston but I'm a believer in OEM. Any suggestions?
Sorry if this needed to be in my prievious thread, if so, Mods please move it.

**ringadingh** · 10-22-2009, 08:51 PM

Its sounds like a piston ring got caught in the exhaust port and broke the ring land. Id recomend an OEM piston and rings instead of aftermarket. Ive replaced many in my day and usually the OEM outperform the aftermarket pistons. I only use aftermarket if the stock ones are not available anymore.

bucfan11 · 10-22-2009, 08:57 PM

Quote:

Originally Posted by Ringadingh

Its sounds like a piston ring got caught in the exhaust port and broke the ring land. Id recomend an OEM piston and rings instead of aftermarket. Ive replaced many in my day and usually the OEM outperform the aftermarket pistons. I only use aftermarket if the stock ones are not available anymore.

I would say that's exactly what happened! Just bad luck or something else?

**ringadingh** · 10-22-2009, 09:13 PM

Check the exhaust port for sharp edges, especially on the top and bottom. There should be a slight chamfer around the ports.
Make sure you check the ring end gap also, if its to tight the ring will expand and bind in the cylinder.

bucfan11 · 10-23-2009, 02:38 PM

It looks new on the inside of the motor. My
concern is the exhaust valve. It looks like the ring may have caught on it
as it looks like one side of it sticks into the cylinder maybe 1/2 mm. When
I tear it all down, I'll see if there is an adjustment.

Rob

**ringadingh** · 10-23-2009, 07:25 PM

Does that motor have a variable height exhaust port? You have to make sure that it working perfectly before you install the new piston and rings.

macmac · 10-23-2009, 07:37 PM

A chip, or an erroded area missing metal? A chip would show as a fractured hunk of missing metal heat errosion would be fire cut and cause scoring.

What about the head? Is it free of any marks? That would be strange if it was....

bucfan11 · 10-23-2009, 08:03 PM

Quote:

Originally Posted by macmac

A chip, or an erroded area missing metal? A chip would show as a fractured hunk of missing metal heat errosion would be fire cut and cause scoring.

What about the head? Is it free of any marks? That would be strange if it was....

It is a chip, the motor never ran hot. It ran perfect and then would not start. No marks anywhere. Good luck I guess. Now if I can figure out how/if I can adjust that valve. Don't know if it's adjustable. It is spring loaded, I can push it back with my finger.

**ringadingh** · 10-23-2009, 09:16 PM

I don't think the valve is adjustable, but you don't want a nick or chip to be able to catch on the new ring, you should let someone look at it that is familier with them. They should be able to tell you if everything is ok to put back together.

rflnomad · 10-25-2009, 08:32 PM

Everything Ringading said is 100% true!
Also, make SURE the exhaust does not still have the 'piece' in it.
I also am a fan or OEM when avalible. Wiesco make a good piston, but can be heavier than stock.

10-22-2009, 07:01 PM	#1
bucfan11 Jr. Member Join Date: Oct 2008 Location: Lakeland, Florida Posts: 48	OEM or Aftermarket Piston? Tore my son's 06 RM250 head off and there is a chip out of the front of the piston. I was amazed at how clean everything was...looked almost new. There is no scarring on the cylinder. I hope the chip blew out the exhaust. Aftermarket offers a two ring piston but I'm a believer in OEM. Any suggestions? Sorry if this needed to be in my prievious thread, if so, Mods please move it. Login or Register to Remove Ads
	0

10-22-2009, 08:51 PM	#2
ringadingh Join Date: Aug 2007 Location: Newmarket Ontario Canada Posts: 35,387	OEM or Aftermarket Piston? Its sounds like a piston ring got caught in the exhaust port and broke the ring land. Id recomend an OEM piston and rings instead of aftermarket. Ive replaced many in my day and usually the OEM outperform the aftermarket pistons. I only use aftermarket if the stock ones are not available anymore. __________________ 2002 Nomad aka Bountyhunter VBA #27 VROC #18951
	0

10-22-2009, 09:13 PM	#4
ringadingh Join Date: Aug 2007 Location: Newmarket Ontario Canada Posts: 35,387	OEM or Aftermarket Piston? Check the exhaust port for sharp edges, especially on the top and bottom. There should be a slight chamfer around the ports. Make sure you check the ring end gap also, if its to tight the ring will expand and bind in the cylinder. __________________ 2002 Nomad aka Bountyhunter VBA #27 VROC #18951
	0

10-23-2009, 02:38 PM	#5
bucfan11 Jr. Member Join Date: Oct 2008 Location: Lakeland, Florida Posts: 48	OEM or Aftermarket Piston? It looks new on the inside of the motor. My concern is the exhaust valve. It looks like the ring may have caught on it as it looks like one side of it sticks into the cylinder maybe 1/2 mm. When I tear it all down, I'll see if there is an adjustment. Rob Login or Register to Remove Ads
	0

10-23-2009, 07:25 PM	#6
ringadingh Join Date: Aug 2007 Location: Newmarket Ontario Canada Posts: 35,387	OEM or Aftermarket Piston? Does that motor have a variable height exhaust port? You have to make sure that it working perfectly before you install the new piston and rings. __________________ 2002 Nomad aka Bountyhunter VBA #27 VROC #18951
	0

10-23-2009, 07:37 PM	#7
macmac Sr. Contributor Join Date: Apr 2008 Location: Tamworth New Hampster 06 1600 Posts: 12,484	OEM or Aftermarket Piston? A chip, or an erroded area missing metal? A chip would show as a fractured hunk of missing metal heat errosion would be fire cut and cause scoring. What about the head? Is it free of any marks? That would be strange if it was.... __________________ 06 1600 Nomad Just call me Mac molon labe come and get it
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10-23-2009, 09:16 PM	#9
ringadingh Join Date: Aug 2007 Location: Newmarket Ontario Canada Posts: 35,387	OEM or Aftermarket Piston? I don't think the valve is adjustable, but you don't want a nick or chip to be able to catch on the new ring, you should let someone look at it that is familier with them. They should be able to tell you if everything is ok to put back together. __________________ 2002 Nomad aka Bountyhunter VBA #27 VROC #18951
	0

10-25-2009, 08:32 PM	#10
rflnomad Advanced Member Join Date: Aug 2007 Location: PSL, Fla; Posts: 596	OEM or Aftermarket Piston? Everything Ringading said is 100% true! Also, make SURE the exhaust does not still have the 'piece' in it. I also am a fan or OEM when avalible. Wiesco make a good piston, but can be heavier than stock. __________________ 2005 Kawasaki Nomad, Black & Silver. 2006 Kawasaki KLR650, Lime Green! 2006 Ford F150 SuperCrew, 2WD, 4.6L; white & gold 1965 Pontiac GTO, 389 4 Speed. Bluemist Slate Cruising the back roads, that is living! Member #000033.
	0

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