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Vertex vs ktm oem?? 23 sxf450
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2 stroke Ktm’s have vertex as OEM. 4 strokes use CP as OEM. I think the CP has a better ring design than the vertex 4 stroke pistons. The last few vertex I used in my 350 seemed to burn some oil where the OEM I took out didn’t.
Depending on how many hours are on it maybe just throw some new OEM rings on the stock piston. Thats the route I took on my 450 at 110 hours. Piston still looked new.
Something else to consider when buying KTM 2 stroke top end kit (piston, rings, wrist pin, circles) is that the Vertex branded kit is about 15% cheaper than OEM. Same exact piston but for my bike OEM is almost $40 more.
As above I understood the OEM 4 stroke pistons are CP.
In my last 2 bike I've just put OEM Piston kits in as it comes with everything needed and I felt good value in Europe, in my older 2018 when money was tighter I used the Vertex. I had zero issues and no oil burning and it was notably more powerful than my very worn stock piston.
Pictures below are old OEM and New Vertex
I'm glad some else sees this. I thought KTM used Vertex in all their bikes, I'm coming from a KTM 250SX, so I put a Vertex in my 350. Yea, she burns a little oil. I even put in new valve seals thinking that was the issue, but still a little burn, especially at start up. I'm going back to CP when I do another preventative rebuild this next winter. Vertex is a good company, but I don't think I'll use them in my 4 stroke KTM's again.
The Shop
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OEM is not vertex, it is CP. With that being said, buy a Wossner.
I asked Twisted when I first rebuilt mine what they recommended and they said OEM. They said nothing out there will beat OEM in terms of reliability when it comes to KTM.
I should have clarified. Vertex is OEM for 2 stroke KTMs. Not positive on the newer models but for sure for the older models two strokes they're Vertex.
What other parts do people change for thumper top end? Valve seals? Timing chain?
My 25 350 Factory Edition burned oil on warmup at 30 hours. New twisted development piston (made by JE Piston) and no more smoking.
I have never had as many problems as my 25 ktm 350. Burned oil at 30 hours, starter motor died at 35 hours. But it is the best bike KTM has ever made.
Would certainly do a timing chain and valve seals, its a lot easier when you are already in there, clean the carbon off the valves too.
Assuming you have a fair amount of hours on it atleast 100-150.
Twisted uses OEM rings in their piston!
Yes, that is correct
KTM valves and seats are very good (I don't like their tensioner much) but it's still part of the "top end". And the valve cover gasket and spark plug tube seal can leak after it's been into.
Same could be said for stock KTM clutches. They come with some really good parts from the factory.
The brand always got a lot of abnormal hate, but I’ve seen KTM 4 strokes go an ungodly amount of hours without ever even having the valves checked compared to the amount of Japanese bikes that have already had a top end by then. Monk, on Thumpertalk, documented his journey to 600+ hours on his KTM 350 very well without ever opening it up. He was a local pro/AA offroad rider and I believe it was his practice and race bike. IIRC he retired it to be his wive’s bike and it was still going strong last I saw him post. He was on here too I believe.
I did piston/rings, valve seals, timing chain, and put in a manual cam chain tensioner. The crank measured in spec, so I didn't bother dropping another $1000. 🤣 But, the KTM timing chain is no joke. It's heavy duty compared to other brands I have rebuilt. My next top end will be OEM. I have zero issue with initial oil burn with the OEM piston.
Oem cam chain js $50 vs $70 for pro x!!
Anyone know the difference between these two oem pistons??
Pit Row
When you assemble these seals and tubes, clean the parts to a surgical level of clean (without using abrasives like scotch-brite), and wipe your finger over the surfaces to feel for any nicks or scratches.
I like to apply a minimal amount of silicone dielectric grease ("tune up grease") to the o-rings and rubber gaskets before assembly.
The small amount of inert silicone lube allows the o-rings to settle into place without twisting or abrading during assembly.
I use the same stuff on the o-rings in my two stroke heads.
You could use some synthetic motor oil as an alternative, but dry assembly and surface damage is usually the cause of these post-assembly leaks.
Sometimes, the aftermarket gasket kits are inferior, too.
I guess it's the sizing (I and II)
This.
OEM is just better at least on the MX injected 2 strokes, can't talk for XC and four stroke models.
Vertex is probably just going to do as good but i've also been recommended OEM.
50 hours on my MC 250 2024, 1st top end at 40 hours and it was still somewhat decent, 240€ for the full kit, put on the same size (I).
Going to go for the second at 80 and thinking of selling the bike over 100's...
I figured the same... Wonder if its safe to assume II is the larger one??,
Vertex is the OEM on the two strokes. Whether you buy it in a KTM box or Vertex box it’s the same piston.
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