Posts
246
Joined
10/14/2019
Location
GB
Edited Date/Time
8/27/2020 12:17am
Hi,
I have a 2020 KTM SX65 with only 14hrs from new. I'm having a problem where every time I start the bike from cold it will start fine and then after a minute or 2 of warming up it will splutter and die. It then sometimes starts again for a few seconds and then dies again, and then won't go at all. If I replace the plug it starts up and runs fine from then all day. The problem will happen again the next time I want my boy to use it a few days later. Its literally needing a new plug every ride!
The jetting is completely stock, and suited to our weather conditions here in the UK. I've carefully cleaned the carb out, and have good fuel supply to the carb. The tank vent hose is fine, and all electrical connections seem good. I took the flywheel cover off and all still looks new and clean underneath.
Running 60:1 as the manual recommends.
Can anyone give me an idea of what else to try or look for?
Thanks
Mark
I have a 2020 KTM SX65 with only 14hrs from new. I'm having a problem where every time I start the bike from cold it will start fine and then after a minute or 2 of warming up it will splutter and die. It then sometimes starts again for a few seconds and then dies again, and then won't go at all. If I replace the plug it starts up and runs fine from then all day. The problem will happen again the next time I want my boy to use it a few days later. Its literally needing a new plug every ride!
The jetting is completely stock, and suited to our weather conditions here in the UK. I've carefully cleaned the carb out, and have good fuel supply to the carb. The tank vent hose is fine, and all electrical connections seem good. I took the flywheel cover off and all still looks new and clean underneath.
Running 60:1 as the manual recommends.
Can anyone give me an idea of what else to try or look for?
Thanks
Mark
Could be jetting and air screw
Make sure the coil ground wire is up against case first
If he is not riding it hard enough to keep this from happening this excess will collect and then foul the plug on the next start up, if it sets for a day or two. These little engines needs to be run hard. They are not designed to be putted around.
Try this... At the end of his next ride....You start and run the engine hard to be sure it is cleaned out before you put it away for those few days. If the next time it starts up ok then you have found the issue.
Also be sure the float level has been set correctly and that the fuel is shut off after each ride.
Paw Paw
Based on helping my buddy with his son and about 5 or 6 of his KTM 65's, I'd say you'd probably be best off raising the clip 1 slot and putting a 1-size smaller main in and possibly a 1 size smaller pilot. My buddy ultimately gave up on the Mikuni and went with a Lectron because they frequently travel between 500 to 5,000ft week to week. and he got sick of constantly having to rip the bike apart to make jetting changes.
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Note: It is still possible your kid will foul the plugs. You may also want to try leaner jetting and/or a hotter spark plug until he gets faster.
Nihilo also sells a different needle as part of a jet kit. https://nihiloconcepts.com/collections/ktm-65-sx/products/jet-kit-ktm-65
Did a couple hours on the bike today with the new settings, ran fine although just checked the plug and it looks lean I think?
Pit Row
Paw Paw
Paw Paw
Flash point, so it just stays and lingers in your engine and builds and builds. Swap to any full ester premix, and you will see good results no more hideous black plugs that snuff out due to excess carbon build up. k2 is awesome, iPone is amazing mix, but it has a very high flash point, k2 is close in centistoke rating, but has a much lower flash point. As well, find an iridium plug, and go back up a size on your pilot, your bike IS running lean, and due to your son learning, he’s not spending enough time In the upper rpm range, to warrant a taller main jet.
I'm using Motorex not Motul
I haven't changed the pilot jet
I went down a size on the main jet, not up
Sorry I'm late, but I also had this exact same problem on my KTM SX 65, I had four key things in my solution to it, my bike is now running good, it used to have this problem
1. Open the Seat, then take your air filter out, after you do that, use as much cleaning tool ( I used brake cleaner ) to take out the Green layering over the filter, I am not too sure what it is, it is sticky, so I doubt it is any lubricant, anyway, get rid of all of it, when you finish, the air filter should be white and yellow
2. Drain the Carburetor Fully ( It may have excess fuel if you are not riding hard )
3. After all this, Put in a brand new spark plug, I use a LR8B.
4. After every ride, make sure you turn the fuel tab off, and rev her a lot! You should rev it so much that the bike dies on its own, then put it in a warm storage area, the next day, turn the fuel tab back on, wait a few minutes, then kick, if that is not working, what you can do is put it in gear, pull the clutch in, roll it, drop the clutch, and it should start ( Roll Start )
There is how I fixed my bike, it is now running sweet as long as I follow these steps! Sorry for the late reply though.
Go down one size on the pilot jet. I forget what size that is. Also check the power valve for sticking. It's very common for them to stick and eventually break.
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