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2 Stroke piston life?

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1 hour ago, mrpike18 said:

Because the flat top piston was exclusive to the 1995 year. The 1994 and earlier will not work nor will the 1996 and later. The piston is impossible to find!  I would have to have Wossner make 4 kits minimum. $900. OUCH!!

Not sure but possibly a Beta piston will work . You could possibly put a dome in it and have the head reshaped . IDK 

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Yes but are you likely to do 200 hours on it ?

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Ktm 125 sx 2018, mono piston i do the ring at 10hrs piston at 20hrs, wiseco forged, piston has 0.08-0.10 mm piston to bore clearance after 20hrs... Flat out mx riding national level. In the emx 125 class some teams put new pistons in between each race...

I believe with a 125 you shouldnt mess around really with pistons, 250/300 will last a long time.

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My 2000 KTM 125 EXC original piston lasted 7 years until I dropped it into water. It was my only bike at the time and I was riding it to work daily, as well as offroading it most weekends. Who knows how many hours? 

My early 2000s 300 and 380 still have their original pistons and rings. Spend the money for a good new piston, do the rebuild right and it will last for years.

Edited by sbest
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I have a Trail Tech rad fan hooked up to my Berg TE300 keeping it at 90-95C on hot days, do a lot of technical single track riding with very minimum WFO throttle, use Bell Ray Synthetic 2 stroke oil, Im sure I will have no problem getting 300+ hrs 

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Not a single post in these piston hour threads means shit without an hour meter installed on day 1 and watched religiously as proof. I love when guys “estimate” that they got 300-1000 engine hours when realistically it’s about 1/5 of that.





Exactly!

That's it in a nutshell.


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I have a mechanic that i trust very much that does all the more difficult work on my 23 year old KTM 300. I asked him " What is the longest ( hour wise) that you've seen on a piston and still work well? He told me that with proper maintenance, he has seen bikes with the original piston as old as 300 plus hours on the original piston! WOW!  Thoughts??

Ive seen A racers crack the skirt at 40 hrs.

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For roughly $200.00 bucks it is not worth trying to get crazy amounts of time out of 250/300, if there is a failure you will be spending much more on the cylinder and possibly the bottom if pieces shatter.  I went 100 hours with mixed riding + some enduro and HS racing on mine, piston still looked ok but but I could tell the bike was losing some power.

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On 2/25/2018 at 10:54 AM, -AC- said:

Anybody know when the EXC/XCW started coming with a factory hour meter? My 1995 did not, my 2006 did not (but it was an XC), and my 2017 did.

My 2008 300 XCW came with the factory hour meter...

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My ktm 200 xcw piston was first changed at 97 hours. It could have gone longer some said. Its here 

 

 

The new one has 40 hours as of now. Still look good through the exhaust port. Plan to change it after 90 hours.

 

 

 

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Back in the late 80's/early 90's, I had a 1983 Yamaha DT125 enduro bike.  I rode that bike 2-3 hours almost every day that there wasn't snow on the ground.  I did the top end once in 1991 with a Wiseco, and then still rode 2-3 hours a day until I sold the bike in 1996.  5 years at 350+ hours a year is over 1750 hours.  Much of the riding was topped out in 6th gear, with the tach showing 2000rpm above redline.  :) 

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I rode a 50cc to school every day for 3 years on the same piston.

40kms a day, 5 days a week for lets say 30 months, so around 400 hours on the piston, bike still run just...

But its the same as comparing a f1 engine rebuild schedule and a daily driver engine rebuild schedule. You cant compare...

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On 2/24/2018 at 9:42 PM, pat22043 said:

Don't Wiseco  and other third party vendors have them? 1995 is pretty long ago....

Wiseco does not have it. Believe me, its a tough one. This is not the first thread on the old 1995 KTM 300 piston saga. Some rare ebay possibilities ended up being wrong.  Not worried about anymore. With my riding ability and hours i ride in Michigan along with,annual hours, 17hrs on it now, i will blow the coin on 4 kits in about 3 years. and YES! i do keep track of my hours. It has been suggested in a few posts that most people do not have a clue of the actual hours on our bikes. For those who dont, Shame on you.

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5 minutes ago, mrpike18 said:

annual hours, 17hrs on it now, i will blow the coin on 4 kits in about 3 years. and YES! i do keep track of my hours. It has been suggested in a few posts that most people do not have a clue of the actual hours on our bikes. For those who dont, Shame on you.

I put hour meters on all of the bikes I have bought this century. The KTM 300 had one in the factory computer, but I added them to the CRF230F, the 250XCF and both trials bikes.

I find it interesting that my mental "hour meter" is wildly off (aka wrong) relative to what the actual hour meter shows. What I think of as a 3 hour ride often have only about 1:45 of actual time with the motor running. Sometimes a lot less.

If you watch the "World's fastest Indian" movie, you can see he made his own pistons.....

Edited by pat22043
s/trails/trials/
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1 minute ago, pat22043 said:

I put hour meters on all of the bikes I have bought this century. The KTM 300 had one in the factory computer, but I added them to the CRF230F, the 250XCF and both trails bikes.

I find it interesting that my mental "hour meter" is wildly off (aka wrong) relative to what the actual hour meter shows. What I think of as a 3 hour ride often have only about 1:45 of actual time with the motor running. Sometimes a lot less.

If you watch the "World's fastest Indian" movie, you can see he made his own pistons.....

You have the hour meter because your not a fool. LOL. I used to be back in the mid 80s ,but back then i didnt care about rebuilding a bike that had parts available everywhere.

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4 hours ago, signal15 said:

Back in the late 80's/early 90's, I had a 1983 Yamaha DT125 enduro bike.  I rode that bike 2-3 hours almost every day that there wasn't snow on the ground.  I did the top end once in 1991 with a Wiseco, and then still rode 2-3 hours a day until I sold the bike in 1996.  5 years at 350+ hours a year is over 1750 hours.  Much of the riding was topped out in 6th gear, with the tach showing 2000rpm above redline.  :) 

According to some, your delusional lol. You have about 1/5 of that lol. Joking bro. 

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Some people fix things because there worried it will break. Others wait till it breaks and fix it. Which is more costly can depend but I let my piston go till it stopped working and that took 16 years. Bike was still running but lost power under load while riding dunes on 4th straight day. Few scuffs and had cracks in 3 spots on bottom side of piston so I got pretty lucky. Cleaned power valves and put new top end in it. Got 20 hours on it now and hoping my luck stays good with my trusty steed. Buddys 2016 he got new last year seized on our last ride few weeks ago.

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Wiseco does not have it. Believe me, its a tough one. This is not the first thread on the old 1995 KTM 300 piston saga. Some rare ebay possibilities ended up being wrong.  Not worried about anymore. With my riding ability and hours i ride in Michigan along with,annual hours, 17hrs on it now, i will blow the coin on 4 kits in about 3 years. and YES! i do keep track of my hours. It has been suggested in a few posts that most people do not have a clue of the actual hours on our bikes. For those who dont, Shame on you.
Do you have specs, or better yet, a CAD drawing of the piston? My friend runs a BIG company that makes gears for industrial equipment and transmissions, and he's told me that he can make any part I would ever need. What's the market for pistons and other machined parts that aren't made anymore?

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3 hours ago, mrpike18 said:

Wiseco does not have it. Believe me, its a tough one. This is not the first thread on the old 1995 KTM 300 piston saga.

You do have a piston now, right? I am sure that for a low low fee, you could get any piston replicated. There are firms (probably just a guy in a garage) in Europe (Germany or Austria I think) that make pistons for mid-70s Yamaha TZ750.


Do you  have any idea what is special about it? Strange diameter or piston pin placement? Weird transfer ports cast into the piston's skirt? I would expect that the materials are nothing fancy, just good quality aluminum forging from mid-90s technology.

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On 3/1/2018 at 9:48 PM, pat22043 said:

You do have a piston now, right? I am sure that for a low low fee, you could get any piston replicated. There are firms (probably just a guy in a garage) in Europe (Germany or Austria I think) that make pistons for mid-70s Yamaha TZ750.


Do you  have any idea what is special about it? Strange diameter or piston pin placement? Weird transfer ports cast into the piston's skirt? I would expect that the materials are nothing fancy, just good quality aluminum forging from mid-90s technology.

The only thing that makes it rare is that it has a flat top and the head is was redesigned for that piston only for that year. I repeat ,that is the only year they did that. Sure there are ways around it like using a 1996 piston and getting head work done but im not into that. Not mention that the engine is 23 years old and its a one off year design.  No worries tho. Im good for quite a while with the hours i put on it per year.

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