All

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.

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 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.

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...

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.

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.

Purely conjecture, but this seems like a classic case of hiring a guy because he has the right experience and knowledge, and then refusing to ACTUALLY listen to him. Hopefully he goes on one of the podcasts and tells all.

This post made my energy bill go up by $2 and another acre of local farm land disappeared.