KTM SX65 killing spark plugs every warm up

JB 19 wrote:

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...

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.   

Grovesy98 wrote:

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...

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

Grovesy98 wrote:

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...

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

VeeKay10 wrote:

Hey, is your bike running good now? If it is can you PLEASE tell me what you did, my 2022 is facing the EXACT same problem...

Hey, is your bike running good now? If it is can you PLEASE tell me what you did, my 2022 is facing the EXACT same problem as yours.

Grovesy98 wrote:

This was 3 years ago, i sold the bike a year ago and it was running great with the 517 needle, smaller main jet, air screw...

This was 3 years ago, i sold the bike a year ago and it was running great with the 517 needle, smaller main jet, air screw adjustment, and clearing it out fully at the end of the day 

Grovesy98 wrote:

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...

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

VeeKay10 wrote:

Hey, is your bike running good now? If it is can you PLEASE tell me what you did, my 2022 is facing the EXACT same problem...

Hey, is your bike running good now? If it is can you PLEASE tell me what you did, my 2022 is facing the EXACT same problem as yours.

Grovesy98 wrote:

This was 3 years ago, i sold the bike a year ago and it was running great with the 517 needle, smaller main jet, air screw...

This was 3 years ago, i sold the bike a year ago and it was running great with the 517 needle, smaller main jet, air screw adjustment, and clearing it out fully at the end of the day 

Grovesy98 wrote:

Cheers, he was on a wide open flat track yesterday so was really revving the bike out. On most tracks we go to he's not on...

Cheers, he was on a wide open flat track yesterday so was really revving the bike out. On most tracks we go to he's not on the pipe anywhere near as much. If that doesn't look overly lean I'm tempted to leave it as it is to allow for the slower tracks and more loading up

VeeKay10 wrote:

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...

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.

Grovesy98 wrote:

Cheers, he was on a wide open flat track yesterday so was really revving the bike out. On most tracks we go to he's not on...

Cheers, he was on a wide open flat track yesterday so was really revving the bike out. On most tracks we go to he's not on the pipe anywhere near as much. If that doesn't look overly lean I'm tempted to leave it as it is to allow for the slower tracks and more loading up

VeeKay10 wrote:

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...

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.

Monkeys6.7 wrote:

I’m just assuming that you having a 65cc motorcycle that you’re probably young… so to begin with, do not remove the green sticky stuff from the...

I’m just assuming that you having a 65cc motorcycle that you’re probably young… so to begin with, do not remove the green sticky stuff from the air filter. That’s air filter oil and it plays a vital role in keeping dust from entering your engine. Second off, turning the gas off and revving it until it dies is extremely hard on any engine let alone a two stroke that uses premixed oil to lubricate the bottom end. No fuel running through the carburetor at high RPM means no lube for the bearings/ crank/ piston as well as extremely leaning out your air/ fuel mixture which causes excess heat to build. Read up on jetting correctly and you will avoid having to take these steps that will ultimately end up ruining your engine. Best of luck.