KTM 50 Help

peltier626
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LA US
1/30/2021 4:34pm
Purchased a 2021 50sx yesterday against my better judgement after hearing some horror stories. Son loved it, he's coming from a pw50 for 2 years to a ttr110 that the seat has been cut and lowered. After scanning the manual and an overlook we head to the track today. After about 10 minutes in a pasture at the track he's got the power delivery down and takes about a 15 min break then heads to the main track. After about 20 minutes he runs out of gas (my mistake). I'm used of a couple hrs per tank on the 110. I refuel and the bike does not run correctly afterwards. It bogs and is hesitant. I check the plug, fuel line for delivery and everything seems fine. He goes out in the pasture but it bogs and kills again. I checked for fire and there seems to be fire but very faint. I can't even get it to start at this point. He finishes off the day on the 110. We get home the bike fires right up. The recommended ratio is 60 to 1, I ran the first tank at 50 to 1. Any suggestions? Carb? Ignition? Too rich of ratio?
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kage173
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TX US
1/30/2021 4:41pm
1. Running 50:1 shouldn't be that big a problem
2. Its a KTM 50 there is no help for you
3. I just bought a KTM 50
4. I have a KTM 50 mini that is completely shot and will never run again.
3
RbR
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Saint Paul, MN US
1/30/2021 4:58pm
Your idle jet is plugged. Take it out blow through it make sure that you can see through it clearly. It's a common problem for new machines because there are micro particulates in the fuel tank that make their way into the carburetor. Make sure to install and inline filter. But this will probably happen several times again in the future.
2
OldHalfway
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Pemberton, NJ US
1/30/2021 5:18pm
Ratio should be fine. What were conditions? Did he hit any puddles? These 50s can have stator issues when wet, would seem odd seeing as its new but just putting that out there. I would start by going thru the carb once I have confirmed spark assuming the stator was fine. I've only had the joy of owning a 50 for about 7 months, so I'm far from any kind of authority just thought I'd share.
RY9MX
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Miami, FL US
1/30/2021 5:32pm
With running the tank dry, I would guess you plugged up something in the carb. With my kids, I had to change the bowl gasket every time or it would leak. I keep a few gasket kits around, so every time I pull the carb, I change the gaskets to prevent leaks.

The Shop

4DAIVIPAI2K5
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Coshocton, OH US
1/30/2021 5:47pm
Ktm 50's like to eat stator, an radiators. I agree it's probably something in the carb this time.
2
defeatist45
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Raleigh, NC US
1/30/2021 5:59pm
Check the carb, but go ahead and buy a stator and coil to have in your box. We have loved ours (2011 mini, and 2016 sx) also, keep lots of plugs.
1
DLP600
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Chatsworth, CA US
1/30/2021 6:03pm
RY9MX wrote:
With running the tank dry, I would guess you plugged up something in the carb. With my kids, I had to change the bowl gasket every...
With running the tank dry, I would guess you plugged up something in the carb. With my kids, I had to change the bowl gasket every time or it would leak. I keep a few gasket kits around, so every time I pull the carb, I change the gaskets to prevent leaks.
I agree., clean the pilot jet. When the stator goes out it does not run,
1
GuyWithABike
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TX US
Fantasy
2204th
1/30/2021 6:22pm
Same experience with my 2018. It was particles in the carb. After several cleanings I put an inline filter and it helped. Still have to clean carb almost every time before I go out but we’re once or twice a month weekend warriors.

Honda 50 and 110 require zero maintenance. Just change oil and keep filters clean and they’ve run with no problems for several years.

Now all I need is a mousse for kids size tires. I’m constantly swapping tubes due to them running over mesquite thorns in these Texas pastures.
AngryBear
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Asheville, NC US
1/30/2021 7:40pm
dont believe most of the 50 horror stories you hear. its for some reason a bizarre rite of passage for mini dads to complain about them. my conclusion is it's either their first forray into mini's, or into bikes general. the illogical mechanical scenarios I've seen many mini dads do is baffling and honestly explains a lot of the so called horror stories. i have a husky tc50 (same bike) with 75hrs that's not had anything done to it but change oil every 5hrs, and a top end @ 50hrs. the carb is more out to bog, anytime you are dealing with smaller jets. be very careful with a pressure washer on any bike, that's a big cause of many of the stator/electical issues. get the jetting right, put an inline filter, and enjoy.

the 'problems' dont magically go away when they graduate to the 65's. the main change there is just losing the autoclutch.
4
Bradj70
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San Antonio, TX US
1/30/2021 8:23pm
Our ktm mini went thru the bugs for some time, I found that if I pulled the bowl blew the jets reinstalled it ran fine after... but the bog kept coming back every now and again and I'd have to go thru my cleaning procedure and it work, then one time I found in the slow jet a gooey greenishgoo, and I realized it was or air filter oil I dont know how it got into the jet but I stopped piling the filter so heavily and no more bogs.
49weasel
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CANAL WINCHESTER, OH US
1/30/2021 9:35pm
It’s your overflow hoses under the bike. They don’t cut slits in the hoses and they clog.
4
peltier626
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LA US
1/31/2021 5:45am Edited Date/Time 1/31/2021 5:49am
Thanks for all the input, I was aiming towards trash in the carb and appreciate other folks sharing their experiences. Is there a particular inline fuel filter that is preferred? I will check and keep in mind all these suggestions. Thanks everyone for the input! He absolutely loved the bike and on the way home he kept reminding me that he wants to ride this one instead of the 110.
Hammer 663s
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Forest Grove, OR US
1/31/2021 8:17am
Also make sure the fuel cap/vent line is not plugged. Seen that before.
1
planter
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MD US
1/31/2021 8:34am
* Overflow lines underneath can clog and act like carb/plug issues. Shorten and slit, always check first in deep loams, mud, wet sand.

* jet holes are tiny. run good clean non-ethanol fuel at 60:1

* keep two pugs and two stators with you at all times. If bike acts like its fowling a plug or slowly losing power and you've check vent hoses and plug, then its usually a stator.

*Careful with pressure washer around stator cover. Mud = heat and heat is enemy of stock clutch if they smoke it. Otherwise its a pretty durable clutch if they don't overheat it.

*Radiator will eventually leak and need fixing or replacement due to weak connection point. When depends on how much they jump and fall on them

We had a 2018 TC 50 and so long as you change oil and understand these basics, it was really a good reliable bike.
4
drivrswntd
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Johnston, RI US
1/31/2021 10:18am
AngryBear wrote:
dont believe most of the 50 horror stories you hear. its for some reason a bizarre rite of passage for mini dads to complain about them...
dont believe most of the 50 horror stories you hear. its for some reason a bizarre rite of passage for mini dads to complain about them. my conclusion is it's either their first forray into mini's, or into bikes general. the illogical mechanical scenarios I've seen many mini dads do is baffling and honestly explains a lot of the so called horror stories. i have a husky tc50 (same bike) with 75hrs that's not had anything done to it but change oil every 5hrs, and a top end @ 50hrs. the carb is more out to bog, anytime you are dealing with smaller jets. be very careful with a pressure washer on any bike, that's a big cause of many of the stator/electical issues. get the jetting right, put an inline filter, and enjoy.

the 'problems' dont magically go away when they graduate to the 65's. the main change there is just losing the autoclutch.
Agreed 100%. The issues on these bikes are so over played. 90 hours on an 18 and 45 on a 20 so far and never had a stator issue.

The bog has happened to us and like others have said slit the vent tubes as when they get clogged up it bogs and dies bad.

Also always cold start the bikes on a stand. Due to the clutch design they always start easier on a stand. I’ve also had them out on track they fall, bike dies will not start at all no matter what I do. Roll it back to pits, up on stand and choke on and barn fires right back up.

2
J-Mill
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Cottonwood, CA US
1/31/2021 10:20am
Planter is pretty spot on^^^
Change the oil ever single ride day. Once your kid gets faster you’ll have to become an expert at rebuilding the stock clutch or investing in an IRP Triple Grip clutch. The bikes are also jetted rich from the factory. A good all around setting seems to be a 90main, 50pilot, W7 needle, 262 needle jet, needle set from second clip from the top. From there you can usually dial it in with the air screw or worst case move the needle up or down a clip.
We run Motorex at 50:1 and it’s been solid. We haven’t lost a stator on the 2018 that has a lot of hours on it but the damn clutch has been a nightmare for us. We did have the breather lines from the carb clog with mud. Kid was leading motos and on the last lap the bike bogged and died. Happened twice in one day and was leading both times. One of the worst feelings as a dad! We trimmed them really short and zip tied them out of the way.
Good luck! These thing rip when everything is dialed but there’s a lot of gremlins waiting for you.
peltier626
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1/31/2021 10:33am Edited Date/Time 1/31/2021 2:21pm
Vent lines were Plugged, I shortened and cut a slit. I'll pull the carb and go through it also.
4
peltier626
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2/1/2021 10:53am
Forgive my ignorance but is there a specific inline fuel filter that should be run with a premixed fuel?
klein8
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Waterloo, IA US
2/1/2021 11:11am
You want to read horror stories go to the facebook cobra page . Stick with the KTM get him a on a 65 as soon as possible.
1
CRF505
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Clarkston, MI US
2/2/2021 5:34am
I was just about to type about the vent lines and then read your recent post! Glad you figured it out. I've encountered this as well a few times after the track was watered. We ride in pretty sandy conditions so when wet it sometimes gets packed in the hoses and the bike will bog and stall. You probably figured it out already, but a quick flick from your finger or a clean out with a straight blade screwdriver fixes. It's a bit odd, and I probably need to reroute or snip the lines or something, but it happened to us two or three times last summer too. Let me know if you figure out a good fix for this issue.

Also, my son has a 2018 and in my opinion it runs WAY better at the recommended 60:1. Like you, I thought that sounded a bit lean so I initially ran it 48:1 and then 50:1 but we were fouling plugs, it was smoking, and it was clearly running rich. I switched to the recommended 60:1 and it runs like a champ.

Side note, as klein8 noted, I wouldn't be afraid of the KTM 50. A lot of the horror stories are dated and are applicable to the previous gen KTM 50's. Nothing's perfect, but the new one is a pretty damn good bike. Cobras have their share of problems too.
1
kapaa10
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Vista, CA US
2/2/2021 7:35am
Get the e 50 and you will never have a problem. I built a quick charger and can charge very quickly at the track.
2/2/2021 8:17am
My KTMs have been great, zero issues so far other then 2 broken levers and torn grips but I'm really shocked that's all I've had thus far.
2
drivrswntd
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Johnston, RI US
2/2/2021 9:07am
My KTMs have been great, zero issues so far other then 2 broken levers and torn grips but I'm really shocked that's all I've had thus...
My KTMs have been great, zero issues so far other then 2 broken levers and torn grips but I'm really shocked that's all I've had thus far.
Shouldnt be shocked. The newer ones are pretty good reliable bikes as long as you maintain them. We got 80 hours out of the stock clutch on my daughters 18. Other than that I changed the oil, cleaned air filters, and did tires/chain/sprockets.
1
zeromarine
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Somewhere, AB CA
2/28/2021 1:26pm
J-Mill wrote:
Planter is pretty spot on^^^ Change the oil ever single ride day. Once your kid gets faster you’ll have to become an expert at rebuilding the...
Planter is pretty spot on^^^
Change the oil ever single ride day. Once your kid gets faster you’ll have to become an expert at rebuilding the stock clutch or investing in an IRP Triple Grip clutch. The bikes are also jetted rich from the factory. A good all around setting seems to be a 90main, 50pilot, W7 needle, 262 needle jet, needle set from second clip from the top. From there you can usually dial it in with the air screw or worst case move the needle up or down a clip.
We run Motorex at 50:1 and it’s been solid. We haven’t lost a stator on the 2018 that has a lot of hours on it but the damn clutch has been a nightmare for us. We did have the breather lines from the carb clog with mud. Kid was leading motos and on the last lap the bike bogged and died. Happened twice in one day and was leading both times. One of the worst feelings as a dad! We trimmed them really short and zip tied them out of the way.
Good luck! These thing rip when everything is dialed but there’s a lot of gremlins waiting for you.
When rebuilding the clutch what parts are all needed jw ? Thanks !
AxlBundy
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Saint Paul, MN US
2/28/2021 3:03pm
Depends on whats wore. You should atleast replace the bolts every time you pull them apart. Measure clutch plates, inspect for wear on the ball plate, fit pins, and so on. IRP has a really good video going through step by step a KTM clutch

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