Piston Melting

[265 sleeper]

What does everyone think happened here
http://s1141.photobucket.com/albums/n584/Jacob_Poupart/trx250r%20piston/

[fearlessfred]

lean condition

[265 sleeper]

Thought so thanks . Dam weather change .

[C-LEIGH RACING]

Dont leave out ignition timing, like if it is set to advance or if for some reason it went to far advanced by itself.

Dont leave out octane of gas either.
To low octane & then not match up with the compression will burn off the front of a piston.
92 octane not good for over 180 lbs compression.
Neil

[fearlessfred]

Originally posted by C-LEIGH RACING
Dont leave out ignition timing, like if it is set to advance or if for some reason it went to far advanced by itself.

Dont leave out octane of gas either.
To low octane & then not match up with the compression will burn off the front of a piston.
92 octane not good for over 180 lbs compression.
Neil I may look like a fool ,but I disagree , all those things would result in a hole in the middle of the piston and not the edge,and a lean detonation would or could result in a hole burnt thru on the exhaust side. the exhaust side of the piston is quite a bit hotter than the fuel cooled intake side and if the motor is leaned out whats gonna burn first the edge of the exhaust. pinging or detonation can, cause a hole in the middle of the piston and even broken ring lands . I dont mean any disrespect, because I can asure you that I have nothing but respect,

[265 sleeper]

Deff not ignition no hole or pits in piston . I couldn't hear any detonation unless it was just wide open throttle.

[265 sleeper]

Fuel possible I was running .54 squish I didn't cc it . So not sure on exact ccr but it was a stroker race gas dome from esr so they should have been somewhat close to right cc . I getting it bored have to go 72.5 piston . They have a back order on 72.25 pistons . Hate losing a bore size to back orders .

[fearlessfred]

is the piston fairly new,because it looks clean on the top? the reason i ask is because when i tear mine down you can see were the transfers were cleaning the carbon from the top of the piston .some one on here descibed thie condition as being correct jetting.im not saying its correct,but i jet the main from being to fat to just were it cleans out on the main. they seem to last along time that way. well i hope it just cost you a piston,rings and a hone .even tho i disagree with neil ,i would still check everything he referred to,

[265 sleeper]

The jetting was off I'm sure of just didn't think it was that bad . I tuned her when it was hot didn't rejet when it got cold. It was a fresh piston. My carb clamp snapped the last time I was in the dunes didn't notice till she was idleing high by that time sand had got in my motor so new clamp roll wit it. Changed the piston when I got home . Then this happened .

[All250R]

It could be a combination of things that could be alleviated by addressing one or a couple items. The problem obviously is that the piston is not able to shed the heat being put into it fast enough. You can reduce the amount of heat being generated, like richening the jetting down, lowering compression, or backing off the timing, addressing a potential air leak; and/or you can figure out a way to get the excess heat out of the piston. Externally from the engine is the coolant system. Sometimes aftermarket heads have sharp edges in the coolant exit port that radiusing helps move flow faster out of the head. And/or the radiator may not be able to keep up with the heat being added to the coolant. Sometimes blockages like big bumpers, mud, big, fat, rock guard fins hinder the ability for air to make its way through the radiator.

To recap, check multiple points of the system, address easy, obvious trouble areas, and then move on to other solutions from there.

[C-LEIGH RACING]

Originally posted by fearlessfred
I may look like a fool ,but I disagree , all those things would result in a hole in the middle of the piston and not the edge,and a lean detonation would or could result in a hole burnt thru on the exhaust side. the exhaust side of the piston is quite a bit hotter than the fuel cooled intake side and if the motor is leaned out whats gonna burn first the edge of the exhaust. pinging or detonation can, cause a hole in the middle of the piston and even broken ring lands . I dont mean any disrespect, because I can asure you that I have nothing but respect,

Hold on now, I've not said anything about anybody & I for sure would not call anybody a fool.

My reply I guess didnt read right or could have been misdirected.
Maybe I should have said, check these things as well, just to rule them out before you run it hard again.

Anytime a piston has melted, it will be from a lean condition created from something not working right or either an air leak.
Where the melted part on the piston is located, will around 85% tell the story of what caused it to do that.
The other 15%, could be by chance was several things happened altogether at the same time.

It is not my intention to come on here & give misleading information. The information I give, comes from years of holding things in my hands, studying the failed parts, reading peoples post with the same problem & the results from their findings & searching as to why that part is damaged like it is.

I just dont have time to come on here & ramble about something I dont know about or that I've never touched with my own hands.

If what I listed is wrong, then I can stand corrected & admit it, but if I am, then every piston I've ever held in my hands that looked like that one since 1968, has mislead me as well as what I've learned from many of top 2 stroke engine builders from around the world.
Neil

[265 sleeper]

I POSTED SOME MORE PICS ON PHOTO BUCKET . THAT PISTON WAS FRESH FOR HALLOWEEN WEEKEND . I GOT TO RIDE ALL WEEKEND RUNNING THE PISS OUT OF HER . THEN CAME HOME RODE A FEW DAYS . WHEN I WAS RIDING SHE JUST KINDA CUT OUT I BURNT A FEW PISTONS IN MY LIFE AND KNOW THE FEELING. I WAS TRYING TO LIMP BACK WHEN SHE JUST LET GO HAD NO COMPRESSION SHE LEFT ME STRANDED ABOUT 8 MILES FROM THE HOUSE . THIS WHERE I'M AT NOW. Don't worry Neil . This is why I asked what you guys think . Everybody got some kind of useful info from what they experienced . Before these forums days. It was a little harder to find out info. The guys who did know something just wouldn't say anything. A lot of trial an error . You never know till you try or ask. Who would of thought these R's could do what they do now 15 years ago.

[fearlessfred]

Originally posted by 265 sleeper
I POSTED SOME MORE PICS ON PHOTO BUCKET . THAT PISTON WAS FRESH FOR HALLOWEEN WEEKEND . I GOT TO RIDE ALL WEEKEND RUNNING THE PISS OUT OF HER . THEN CAME HOME RODE A FEW DAYS . WHEN I WAS RIDING SHE JUST KINDA CUT OUT I BURNT A FEW PISTONS IN MY LIFE AND KNOW THE FEELING. I WAS TRYING TO LIMP BACK WHEN SHE JUST LET GO HAD NO COMPRESSION SHE LEFT ME STRANDED ABOUT 8 MILES FROM THE HOUSE . THIS WHERE I'M AT NOW. Don't worry Neil . This is why I asked what you guys think . Everybody got some kind of useful info from what they experienced . Before these forums days. It was a little harder to find out info. The guys who did know something just wouldn't say anything. A lot of trial an error . You never know till you try or ask. Who would of thought these R's could do what they do now 15 years ago.
well said.I admire neil as much as everone else on here and he is much needed in the 250r community. neil offers help without trying to sell himself like others do. neil please dont be offended because my opionion differs from yours

[C-LEIGH RACING]

Oh I'm not, just rambling on the computer.

When you have a forum like this & questions asked, you need several different views, from several different people, to get down to the root of the problem & hopefully solve the problem for the owner. At least give them enough info they wont have to go threw it again.
Sometimes, when you question someones thoughts or reasons, it tends to really get in depth & the person giving that information really goes into more details of what it could be.

Its a trickery of the mind of sorts, to make one give details, where as before it was just a fast few words answer & the owner left with a hint of details.

Its all good, cause we need to help each other much as we can, with what we know in a attempt to save 250R owners some money & make them realize even more how much they are saving by just owning a 2 stroke.

Bad as the economy is right now & tight as money is, the 2 stroke makes more since than ever today with no more than it takes to keep it running.
Neil

[265 sleeper]

Its all good, cause we need to help each other much as we can, with what we know in a attempt to save 250R owners some money & make them realize even more how much they are saving by just owning a 2 stroke.

Bad as the economy is right now & tight as money is, the 2 stroke makes more since than ever today with no more than it takes to keep it running.
Neil [/B][/QUOTE] your right I spent under 1500 on esr cylinder kit crank pipe carb cr ignition and angle porting tool . Now I did the work my self . Saved some money doing so. But still beat spending double on a 4stroke and going half the speed hahahahaha. Long live 2stroke .

[Langbolt]

Originally posted by 265 sleeper
My carb clamp snapped the last time I was in the dunes didn't notice till she was idleing high by that time sand had got in my motor so new clamp roll wit it.

It really Sucks that when a clamp lets go it can have such devastating results. Silmilar to guys that don't put enough oil or any oil on their Air Filter.

I noticed the black coloring all around the piston below the second ring....tells us that the clearance was too excessive....also look at how polished the piston is on the skirt....no more horizontal machine marks....a rough piston surface holds the oil just like the sleeve does to lubricate and keep the motor cool....when this goes the temps go up!

Just glad the piston let go where it did......if it fractured you could have wrecked the bottom end and would have been a lot more $$$

Good break-in could have been what saved you too! The piston was well seasoned.

my 2 cents

:devil:

[265 sleeper]

In the pic you can't see it but the piston still had the oil ring grooves around the piston . Looked new if you looked around the scaring and the spot melted . And the clamp problem was on the piston before this one . I changed out that piston . Then this happened . Still same bore. It only shows the dark ring because the piston was melting so going right behind the first ring till she lost compression on the bottom ring. Needless to say run lean and your f**ked

[machwon]

Originally posted by All250R
It could be a combination of things that could be alleviated by addressing one or a couple items. The problem obviously is that the piston is not able to shed the heat being put into it fast enough. You can reduce the amount of heat being generated, like richening the jetting down, lowering compression, or backing off the timing, addressing a potential air leak; and/or you can figure out a way to get the excess heat out of the piston. Externally from the engine is the coolant system. Sometimes aftermarket heads have sharp edges in the coolant exit port that radiusing helps move flow faster out of the head. And/or the radiator may not be able to keep up with the heat being added to the coolant. Sometimes blockages like big bumpers, mud, big, fat, rock guard fins hinder the ability for air to make its way through the radiator.

To recap, check multiple points of the system, address easy, obvious trouble areas, and then move on to other solutions from there.

So is this one of those new ESR cylinder kits? Originally I was thinking octane problem, not sure if I remember your fuel used.

[265 sleeper]

Yes it is one of the new kits 499 .well worth the price. I was running c12 . When I go to tune her in this time Im useing a exhaust temp gauge to be accurate . No more checking the plug. Then ima run a br9eg . Iriduim style. Just so next time ill burn the plug and not the piston.

[265 sleeper]

Got my new piston in today . Now just finding someone to bore it in a short notice .

[solid250r]

lost piston on my esr 310 looked the same as your pics, water leak at stud and exhaust bolt hole, fixed leak ran for a while and sold pos cylinder

[fearlessfred]

Originally posted by 265 sleeper
Got my new piston in today . Now just finding someone to bore it in a short notice . dont send it to ct racing. allen knowels sucks .i had to order a piston from him,because I have an early ct pro x 310 and the crown of the piston is cut at 5 degrees.so acording to allen i had to buy the piston from him. well needless to say he offered to bore it and make sure that everything was good to go .I sent it to him and aprox.2 weeks later I get it back and the piston wont even slide all the way thru tha cylinder. at the bottom four corners of the cylinder it is 2 to 3 thousanths smaller. so I call him up and ask what did he do, hone it to size and he said no, that they never do that. he said he would fix it ,and that he would send a shipping label ,2 phone calls and a month later,still no shipping label.i cant beleive i knew that he sucked and i sent my stuff to him anyway. just venting.shoulda started my own thread sorry

[265 sleeper]

I hear ya . Can't stand crooks like that . I ran into that before with other people . But na I might send it to Marvin at kustom Kraft. But don' t want to spend a extra hundred bucks on just shipping. I'm trying to get some one local to do it just not sure on a short notice. I'm getting a bore bar and hone. So I don't have to wait on any one to do any of my work. All in house is nice . But 900 on a good bore bar nd hone is steep price to pay for quickness

[265 sleeper]

Originally posted by solid250r
lost piston on my esr 310 looked the same as your pics, water leak at stud and exhaust bolt hole, fixed leak ran for a while and sold pos cylinder

I ran into a few problems with mine just nothing that wasn't fixable . Blown head gasket due to head studs backing out . Fixed. Then the clamp breaking . Fixed. Running lean going to fix. Lol.. just keep going till its right. Just sucks no 72.25 pistons right now so 72.50 is the one I have now. Just means I'm now around a true 310 cc bike. Can't wait to see the differance in power .

[265 sleeper]

Well getting my cylinder done today . Going to start putting her back together tonight

[machwon]

265 sleeper, I think one of the problems is with the cylinders ability to keep cool above the exhaust port. I have not heard of one of these cylinders that hasn't stuck a piston, someone chime in if they never had an issue.

I have done a couple where we modded the water jacket above the exhaust port so the coolant flow through. No news is usually good news and no one has told me the piston stuck after we bored them and modded the water jacket. Take a look in the water jacket, above the exhast port and where the two front head studs are at. There is not an 1/8" of passage through there and if the coolant were to take the path of least resistance then it would tend to not flow across the exhuast port (the hottest side of the cylinder). Even the OEM head gaskets send more coolant to the exhaust side of the cylinder.

I called on this last week and they claim they changed the taper of the piston recently. I have a couple new other versions of 72mm pistons but the tapers are all the same.

[machwon]

I can try and get you a pic next week. I'm out of town for a bit, otherwise I would post it right away. The picture may not show that far down in the cylinder, so if my explained area is not clear just let me know.

[265 sleeper]

I kinda remeber what your talking about with how the jacket there is smaller than the rest. Bobizzle was looking at the water neck on the cylinder and the holes are drilled and don't line up there like half and half . I could see there that would be a problem on getting enough flow into the motor . After bobizzle gets my cylinder bored ill take some pics and post it of what I'm talking about and what you are too . Thanks for the heads up .

[All250R]

Originally posted by machwon
265 sleeper, I think one of the problems is with the cylinders ability to keep cool above the exhaust port. I have not heard of one of these cylinders that hasn't stuck a piston, someone chime in if they never had an issue.

I have one running around that hasn't had any issues with the setup as from ESR. In other words, I just assembled the engine without any modifications, and it is still running fine without issues. I did have a customer recently seize for the second time with a 4 corner seizure, however with wossner pistons setup at the typical clearance for wossner. He says the coolant temperatures are normal. There is a thread on trxnet from carlos last august about these cylinders requiring extra clearance than normal. If it's required to clearance them above the norm, then the piston possibly has issues shedding heat in this cylinder in general. I wonder if the main issue is related to heat transfer from the liner to the cylinder casting - possibly a problem with liner installation. Setting the clearance wide is a work around for incomplete R&D on ESR's side...

[solid250r]

after i sold esr310 pos cylinder i got a used pro-x 310 out of ebay, no more problems. my cousin got a new esr 310 more than a year ago that siesed in 45 min, he sent it to carlos and he mill the exhaust water channels and open up bore one thousand more. cousin been racing same 310 for 10 months no problems. my used pro-x 310 has wosner piston and over 60 hrs race time no problems

[machwon]

Picture of the modded side.

[machwon]

picture of the non modded side.

[Trxjim]

Interesting read guys. I have gone through a couple of pistons in my pc2000 powervalve which looked similar to yours. I am planning to back down my compression a little bit to help. But I am also planning on ceramic coating the crown of the piston as well as the exhast ports and head. We will see if it helps. I would like to get the reliability of a four stroke while still leaving them in the dust.