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Folks with 2023 and newer Ktm 2 strokes;
I’ve got a 2025 Ktm 300sx.
The suggested interval for a top end is 15 hours. Are yall doing them that frequently? Any input is appreciated!
Idk why but I have swapped the piston on every 2 stroke I have ever had around 50 or 60 hours just to do it. Usually it's not needed but works for me. I ride them hard but with good fuel and clean filters I bet 80+ isn't crazy. For us mortals 15 hours is way overkill. On the tbi bike make sure to reset the power valve after you complete your toped rebuild. Lots of youtube videos on how. I'd like to add that with the tbi bike make sure to let it warm up on choke until radiator is warm to the touch. People were fouling plugs and couldn't figure out why. The ecu needs to get the mixture right at operating temp before you start riding.
I’ve never once let mine idle until the radiator is warm unless I am breaking it in. I start mine with the fast idle engaged, let it idle about 20 sec to put my gloves and goggles on and ride it easy till the rad heats up. It has never fouled a plug either. I do my piston around 30hrs but I’ll admit it looked great and didn’t need it. (Wossner)
Many variables …your ability level and maintenance program being top variables….I”m a Vet/ Sr A rider, 2023 300SX…. Top end service at 95hrs as I was feeling guilty …still ran great… the powervalves needed a service more than the piston & rings…Majority of that 95 hrs was sand Mx & Gncc type riding, I can still move along a decent pace…I also replaced clutch pack & basket rubber bumpers as preventative maintenance. Currently at 125 hrs, its my do it all, practice bike…remapped ECU by John Ross,.50:1 Amsoil dominatior with 25% C12 to attain around 95 octane..about every 20hrs I will replace spark plug & reset powervalves…love this bike, likely buy another soon, waiting for the big KTM sell off😂
Yea 20 or 30 seconds is about all it takes. Just don't hop on and take off.
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Is this mostly for the spark plug issue or are you saying it has ramifications for internals as well?
When I got my xc sometimes I would get to excited, start it up and take off. Would notice the bike ran like crap and eventually fouled a plug. Apparently you are supposed to hit the hot start and let it warm up for a few seconds to allow the ecu to get the mixture right. So I started doing that and no issues and she rips.
I don’t like to start it and put it under load instantly, but it doesn’t need to sit and idle all day either. I am just saying that’s what my routine is. I can start it and let it idle for minutes and have no issue. I’ve never once fouled a plug. Mine has also been tuned since like 20hrs. Even stock it never fouled a plug, although it was for sure rich at idle and low rpm.
I just go easy on it until it warms up.
It sounds to me that fouling sparkplugs has become issue because riders are so used to fours strokes these days. Even with old carbureted two stroke bikes you don't want to leave your bike idling longer periods because you are going to foul your plug if you aren't blipping the throttle.
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