Hey guys, yes another mini-Dad/50 help post. I've searched but couldn't find anything helpful...
I just bought my 4 year old a used 2023 KTM 50 SX Mini as an upgrade to his PW50. He has been winning his class on the PW all year, and he's a tall kid. So between ringing the piss out of the PW, plus being tall enough for a mini... i pulled the trigger. Racing 2 classes for now.
Okay so I bought the bike used, which is always scary but they don't make these things new anymore so a 2023 was the best i could find. The bike has about ~50 hours on it, and a fresh top end. When I got it home, I checked/cleaned the carb, changed the oil and air filter, checked all the nuts and bolts, and then went ahead of ordered new plastics, graphics, tires and grips. The bike looks and runs great, no major complaints. I've taken it out maybe half a dozen times now and my son is loving it, asking to sell the PW because he wants to only ride this. Separate conversation haha. Well last weekend, he wanted to practice riding on the main track with me. So we took him out for kids practice, and lo-and-behold he gets into the deep wet stuff and goes down. No big deal, simple tip over. So I set my bike down, get him and the bike off the track, and then go to kick it and WOW. I sat there in 100 degree weather with full gear on, kicking that flooded little 2 stroke for a good 10 minutes before I gave up. Walked it all the way back to the truck, got it on the stand and spent another 10 minutes kicking it before FINALLY it turned over and cleared out. It was so hard to kick, that there is a 0% chance he can race this thing because if heaven forbid he tips over, it's game over. Must be on a stand, and even then is next to impossible to get started.
Anything that I should consider checking? It starts up fairly easily when cold or hot. It runs great otherwise. But if this thing tips over, it's impossible. I grew up on 2 strokes so i know the drill. Hold it wide open and kick it into submission. But I'm telling you, it cannot be started off the stand and without significant effort. Yes I know these things are tricky, but I watch a million other kids tip over all day at the track and their bikes are not hard to start like this. I had several other mini Dads coming up to me trying to offer help, and then walking away saying they don't understand what's going on. So something isn't right.
Where do I start? The carb is good I think. The fact that it starts fine any other time, and runs great... I would think the carb is good. Plus I just took it apart and cleaned everything. The prior owner told me this thing was impossible to start when flooded, so I know it wasn't something I did. So what next? Trying to pick the brains of people that have been through this. Spark plug? Stator? I would say top end up it just got rebuilt professionally. Air filter is good. Gas is good, it's fresh and is 91 ethanol-free mixed at 60:1 (oil injection system removed by prior owner, which I'm fine with). I've heard there's something with the vent hoses, but I only see one vent hose coming out of the case? And what is this trick I see people doing where they are tilting the 50's on their front end to help start them? Does that apply to the SX Minis? and if so, what does it do?
Any help is appreciated. I'm scratching my head and this is driving me nuts. I take immaculate care of my stuff, and this is why I don't buy used. But with them discontinuing these bikes, I had no choice.
Thank you in advance!
The tipping on the front wheel is to get fuel to the engine. They are finicky little bikes. How does he ride it? Is he blipping the throttle? Bike loading up?
Did you turn the fuel off when you held it wide open and kicked?
Not a blipper, he's very steady wwith the throttle. No i dont turn the fuel off, never hAve for prior 2 strokes. Woukd recommend turning off fuel, then hholding wide aND kicking?
Thanks for the reply!
Has the big started since?
Things to check, I’ll leave the carb out since you said you cleaned it:
Compression. Coil. Stator.
I have had coils and stators be fine prior to the bike getting to operating temp, so warm that bike up. Plenty instructions on the web using the ohm meter for it.
Doesnt matter if it was just rebuilt, check that compression, while you’re at it check the reeds too. One of mine had two hours on it and the ring let go. Welcome to 50s
Yes. Turn off. Tip bike so it over flows out the carb. WOT and kick.
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Same thing happened a few times to my kid on the SX50. Have to turn the fuel off, lean to the side to empty the bowl, fires right up. Another thing to check is you might be lean or rich on the pilot jet and/or air screw. If you have hair now you might as well shave your head because these things will age you quickly haha. It’s a fun time and goes by quick but damn these things are finicky. I’d really consider a Cobra when he out grows the Jr. Not that they’re any less maintenance but they smoke the KTM if the kid can utilize the power.
100% STATOR.
Order a couple.
Yes,you must lift the rear wheel to start it.
Do NOT kick the living shit out of it.
One SLOW kick through the stroke,back to the top and a good solid kick.NO GAS.Rear tire MUST BE off ground.
You haven't mentioned this and I'm only assuming as he is off the PW but my guess is you have the clutch all the way down?...Great for him but in turn makes the bike hot as hell.
Hence all I have said above ...once you advance the clutch to 8-10 clicks out ,you can kick the bike on the ground.
Spark plugs and stators my man...don't loose your mind on the other shit.
Yes,you may have the odd occasion you need to drop the bowl on the carb but otherwise STATOR.
Vent hose shment hose.
You will only tip the bike on its nose for 10 seconds at the start of your day.....choke on....slow kick through the stroke...return and kick...no gas....choke on until she tells you to turn off after firing...NO gas.
Your going to have some frustrating days at the track with him.Breathe.
My name is OutBored and I'm a recovering KTM 50 dad ❤️🩹
Great advise for the OP Outboard and good luck with your recovery...hahaha
Hot bike, won’t restart-stator
Check the carb vent hoses. I had to cut slits in the bottom of my kid’s 50 because they were plugged with mud and the bike acted like it was running out of fuel.
The stators are easy to check with a meter to see how far gone they are. We have alot of hours on these engines and have had all of the challenges people list. They are picky little bikes.
I second the procedure above: Fuel Off, tip bike to drain carb, fuel on, fire it up.
If that isn't working it's usually telling me the compression is down and it's time for a top end. Or that the stator is headed out. We keep a spare stator and a spare top end with us as both can be done pretty quick on these little bikes. But honestly nothing drives a person to consider electric motors faster than a KTM 50cc motor
Had similar issues with a new '23 50SX. Slit the carb vent tubes. When they get a little wet or muddy, it'll die.
These bikes really aren't that bad. ~80 hours on it now, stock clutch, stock stator, JETTING!!! They come PIG rich. I went through the gambit of pilot, main, needle positions and made the world of difference. Bike starts 1st kick on the stand cold with choke. Starts hot on the ground, even after a tip over. Running 91 pump gas 60:1 Motorex 2t per manual. For what it's worth, I did go back up a main size to help with engine / clutch temps at higher loads. Was running stock pilot, needle #2, 80 main. Went to 85 main. 83 would've been perfect 🤔 Stock main is 95! Check your plug color and piston wash.
If you do flood it out, throw the plug away and start fresh. You can sometimes as mentioned before, turn the gas off, tip bike over to empty bowl and kick with throttle wide open. (mixed results)
Thanks, guys! So the rrecurring theme is spark plug, and then change the starting technique to a fuel off, choke on, hold wide, tilt the bike on the front end, and kick it a few times. If those don't make a difference, stator is next. If none of that works, sell it and force him on to a full size 50 (new) and pray we don't have the same issue 😅
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