After I cleaned it up good with scotchbrite pad, I notice the shinny dime sized area directly below the spark plug.
Whats going on?
It has like 250 hours on it and stock jetting except for when I go to Colorado.
BB
Tell me about this piston....
Started by
BlackBuzzard
, Feb 28 2012 01:50 PM
31 replies to this topic
Posted 28 February 2012 - 01:50 PM
Was replaced with OEM as part of fresh cylinder head project.
After I cleaned it up good with scotchbrite pad, I notice the shinny dime sized area directly below the spark plug.
Whats going on?
It has like 250 hours on it and stock jetting except for when I go to Colorado.
BB
After I cleaned it up good with scotchbrite pad, I notice the shinny dime sized area directly below the spark plug.
Whats going on?
It has like 250 hours on it and stock jetting except for when I go to Colorado.
BB
Posted 28 February 2012 - 02:39 PM
It looks like it had some kind of corrosive fuel run through it. The dime sized thing in the middle is where it was cut off a larger part in the machining process. There is something funky going on with that wear on the top of the piston.
I can honestly say Ive never seen a forged piston that looked like that on the top. Its like it was allowed to corrode, then bead blasted, then run and then cleaned again.
Is that out of a CRF?
Really looks like a cast piston to me, but I dont know of any cast piston, 4 valve engines off the top of my head. It also doesnt look like it has a dome of any kind either. The 02-03 was the only "flat top" piston OEM honda made for the CRF and I only say "flat top" because it didnt have any kind of dome.
I can honestly say Ive never seen a forged piston that looked like that on the top. Its like it was allowed to corrode, then bead blasted, then run and then cleaned again.
Is that out of a CRF?
Really looks like a cast piston to me, but I dont know of any cast piston, 4 valve engines off the top of my head. It also doesnt look like it has a dome of any kind either. The 02-03 was the only "flat top" piston OEM honda made for the CRF and I only say "flat top" because it didnt have any kind of dome.
Posted 28 February 2012 - 02:40 PM
BlackBuzzard, on 28 February 2012 - 01:50 PM, said:
Was replaced with OEM as part of fresh cylinder head project.
After I cleaned it up good with scotchbrite pad, I notice the shinny dime sized area directly below the spark plug.
Whats going on?
It has like 250 hours on it and stock jetting except for when I go to Colorado.
BB
After I cleaned it up good with scotchbrite pad, I notice the shinny dime sized area directly below the spark plug.
Whats going on?
It has like 250 hours on it and stock jetting except for when I go to Colorado.
BB
Take a pic of the side of it. That is the point that matters most.
Posted 28 February 2012 - 02:53 PM
Shawn_Mc, on 28 February 2012 - 02:39 PM, said:
It looks like it had some kind of corrosive fuel run through it. The dime sized thing in the middle is where it was cut off a larger part in the machining process. There is something funky going on with that wear on the top of the piston.
I can honestly say Ive never seen a forged piston that looked like that on the top. Its like it was allowed to corrode, then bead blasted, then run and then cleaned again.
Is that out of a CRF?
Really looks like a cast piston to me, but I dont know of any cast piston, 4 valve engines off the top of my head. It also doesnt look like it has a dome of any kind either. The 02-03 was the only "flat top" piston OEM honda made for the CRF and I only say "flat top" because it didnt have any kind of dome.
I can honestly say Ive never seen a forged piston that looked like that on the top. Its like it was allowed to corrode, then bead blasted, then run and then cleaned again.
Is that out of a CRF?
Really looks like a cast piston to me, but I dont know of any cast piston, 4 valve engines off the top of my head. It also doesnt look like it has a dome of any kind either. The 02-03 was the only "flat top" piston OEM honda made for the CRF and I only say "flat top" because it didnt have any kind of dome.
Its the original piston from an 03 crf450r - Canadian version.
I think the scotchbrite pad cleaned up the high points really shinny while the pits stay black from the usual combustion residue. In other words the photo enhanced the visual effect of pitting. There is some sort of surface texturing treatment on the oem pistons, right?
Always have run high octane pump gas with fuel preservative added.
I dont recall the oem replacement I stuck in having the shinny center thing in the middle......makes sense that its a result of manufacturing process.
BB
Posted 28 February 2012 - 05:39 PM
Quote
There is some sort of surface texturing treatment on the oem pistons, right?
No, there isnt. thats why I asked. The piston that came out of my 03 looks nothing like that on the top.
The skirts though look really good. Guessing. I wouldnt have gone further than 50 hours based on the skirt and the amount of coating left and the Lathe marks.
All those lathe marks were worn all the way off on mine on the thrust side of the piston at 120 hours.
Posted 28 February 2012 - 10:47 PM
Looks exactly like the piston I pulled out of my '02. Same dimples all over the crown.
The old piston from my '02 looks and feels like a casting to me, and the raised bit under the sparkplug hole leads me to believe that's where they machined the pouring runner off (or injection runner if it was high pressure die-cast).
The old piston from my '02 looks and feels like a casting to me, and the raised bit under the sparkplug hole leads me to believe that's where they machined the pouring runner off (or injection runner if it was high pressure die-cast).
Edited by Lead Head, 28 February 2012 - 10:56 PM.
Posted 29 February 2012 - 05:37 AM
whats interesting to me is that the dimple in the middle doesn't have any of the texturing the rest of the piston top has.. i have only had 04 and up so have no insight on this, but like some of you guys I'm curious if this piston came this way on top or not..
Posted 29 February 2012 - 06:34 AM
I would think it must have looked that way when it was manufactured because, like MELK-MAN said the dimple in the middle lacks the texturing that the rest of the piston has. Wouldn't corrosive gasoline have effected that dimple as well?
Did some google searching though and havn't found any other pistons that look that way.
Did some google searching though and havn't found any other pistons that look that way.
Posted 29 February 2012 - 07:31 AM
There is nothing out of the ordinary with that piston!!!! The round spot in the middle is from casting and manufacturing process. The small dimple like look to the rest of the crown is also normal! They dont smooth or posish the top etc. Its not from corrosion at all!!
Posted 29 February 2012 - 08:02 AM
I can confirm the '02s came like this. My '02 Piston looks exactly the same.
Posted 29 February 2012 - 11:07 AM
I had to go out and look again at my old piston. It does have some of that grain in the top of the raw forging but no where near to that extent. Its gotta be something/some kind of effect the camera is putting on there. One thing is definitely different than mine is the dome. Mine is machined entirely. No remnant button in the middle.
Are you sure that's the original piston? Not so much regarding the top, but the skirt. That piston doesnt look like its got anywhere near 250 hours on it unless it was just trail ridden kinda easy.
Are you sure that's the original piston? Not so much regarding the top, but the skirt. That piston doesnt look like its got anywhere near 250 hours on it unless it was just trail ridden kinda easy.
Posted 29 February 2012 - 11:29 AM
Nope, grain looks just like that in person. I don't think it's just a coincidence that the raised machined pad on both our pistons would still be smooth, while the rest of the piston is pitted. The raised pad makes me think these pistons are die-casted, and the mold fill port was simply machined off afterwards
The bottom of my piston is listed as an "HF2".
The bottom of my piston is listed as an "HF2".
Posted 29 February 2012 - 12:20 PM
Lead Head, on 29 February 2012 - 11:29 AM, said:
Nope, grain looks just like that in person. I don't think it's just a coincidence that the raised machined pad on both our pistons would still be smooth, while the rest of the piston is pitted. The raised pad makes me think these pistons are die-casted, and the mold fill port was simply machined off afterwards
The bottom of my piston is listed as an "HF2".
The bottom of my piston is listed as an "HF2".
A cast piston with that little of skirt wouldnt last 15 hours. Trust me, its forged.
Watch this. It shows how JE goes about it, but the OEM pistons are done basically the same way, out of a raw forging.
Posted 29 February 2012 - 12:50 PM
Stock Honda Pistons are CAST!! Not sand cast but cast. JE and Wisecon are forged. Thats why they look different and take different ring gaps etc........
Posted 29 February 2012 - 12:54 PM
http://www.google.ca...Fcfk6lpUx8jHWuw
READ it!! Some decent info in a short article.. Stock crf pistons are CAST!!!!!
READ it!! Some decent info in a short article.. Stock crf pistons are CAST!!!!!
Posted 29 February 2012 - 12:56 PM
Buy the way! That piston in the article is from a CRF. On the left etc.
Posted 29 February 2012 - 04:29 PM
Shawn_Mc, on 29 February 2012 - 11:07 AM, said:
I had to go out and look again at my old piston. It does have some of that grain in the top of the raw forging but no where near to that extent. Its gotta be something/some kind of effect the camera is putting on there. One thing is definitely different than mine is the dome. Mine is machined entirely. No remnant button in the middle.
Are you sure that's the original piston? Not so much regarding the top, but the skirt. That piston doesnt look like its got anywhere near 250 hours on it unless it was just trail ridden kinda easy.
Are you sure that's the original piston? Not so much regarding the top, but the skirt. That piston doesnt look like its got anywhere near 250 hours on it unless it was just trail ridden kinda easy.
Its the original piston......took delivery of the bike in the factory crate back when it was cheaper to get them shipped down from Canada.
This bike has seen many many hours of Colorado 4x4 mountain road riding.......I'm mostly sightseeing in those riding circumstances.
There must be at least a two or three fold difference in wear between full-on racing versus recreational backcountry riding.........right?
BB
Posted 29 February 2012 - 05:18 PM
BlackBuzzard, on 29 February 2012 - 04:29 PM, said:
Its the original piston......took delivery of the bike in the factory crate back when it was cheaper to get them shipped down from Canada.
This bike has seen many many hours of Colorado 4x4 mountain road riding.......I'm mostly sightseeing in those riding circumstances.
There must be at least a two or three fold difference in wear between full-on racing versus recreational backcountry riding.........right?
BB
This bike has seen many many hours of Colorado 4x4 mountain road riding.......I'm mostly sightseeing in those riding circumstances.
There must be at least a two or three fold difference in wear between full-on racing versus recreational backcountry riding.........right?
BB
Ya, because that piston isnt hardly worn at all. Mine at half the hours had 4 times as much wear.
