KTM 50sx mini help

JWW85
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JWW85
Hoping some other current / former mini dads will be able to help guide me here as I've been left scratching my head.

My son moved up to a '22 KTM 50sx mini this winter and it's been going well. On Sunday, we went to a track to practice. He did one ~15 minute session with no issue, then took a break while I went out. About ~5 minutes into his next moto, the rear wheel locked up solid. I think, "great, the clutch went out " and carry it back to the truck to put on his stand.

Fast forward about 15-20 minutes - after I've periodically messed with it and the wheel still being stuck - my 5 year old grabs and spins the rear wheel. It free wheels almost like the front would, if spun. Ok, weird, but I think it's still the clutch. Start it up to check it and the rear wheel doesn't spin. He's done for the day and sticks it out while I ride.

We get home and I start washing all the bikes and gear. Something tells me to check it one more time. Fire the bike up and it works like normal. Now, I'm stumped.

I've taken his bike apart, inspecting everything, and can't see any wear in the clutch parts (plates, basket, etc.), no typical burnt smells, etc.

Has anyone else ran into a similar issue and, if so, what was the cause?

FWIW - I change the oil after every ride day with Motorex, run the stock 9 click clutch setting and am getting an entire clutch pack to have as a back up moving forward.
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J-Mill
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J-Mill 3/22/2022 10:18pm
3/22/2022 10:18pm
These things always have gremlins… We’ve had the rear wheel issue like you’ve had and it was from mud/dirt build up around the front sprocket or the chain guide in the rear. Recently saw a dad pushing a KTM-50 back to the pits thinking the clutch was fried. I grabbed it and rolled it backwards (freed up the rock/debris) and fired it up. All good…. Your boy was most likely spinning the wheel backwards in the pits so it cleared the junk out. If you buy the aftermarket case saver and ignition cover you’ll be able to keep the crap out of there better and less likely to have that happen.
If you’re racing local and not worrying about being AMA legal I wouldn’t wast a penny on the stock clutch and would go straight to the IRP Triple Grip clutch. Light years better than the stock POS on those bikes. If you’re racing AMA and trying to make Loretta’s or Mammoth or whatever, sell the KTM and buy a Cobra immediately (which also have a ton of problems).
Stock a spare stator too…
Good luck my dude and praying you get thru to the 65’s soon. You’ll be a lot happier at the track when you’re done with 50’s LOL….
JWW85
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JWW85 3/23/2022 5:42am
3/23/2022 5:42am
Thanks for the feedback, J-Mill.

That's actually something that I checked at the track and put a Nihilo case saver on for that reason. But, not to say that I simply didn't see the obstruction in the chain guide or it fell out when I was getting it back.

I'll pick up an extra stator and probably go the IRP route for sure.

Other takeaway for me, I guess, is to always bring his PW too as a back up to salvage riding days for him.
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J-Mill
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J-Mill 3/23/2022 1:54pm
3/23/2022 1:54pm Edited Date/Time 3/23/2022 1:54pm
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started with the Nytro oil IRP sells then switched to B&W TrickShift.

Thinking about your issue, the clutch could’ve got so hot it expanded and locked it up. Seemed like after it sat or cooled down it free’d up.
FilthyGrungy 3/23/2022 5:29pm
3/23/2022 5:29pm
Bought an older mini last year. Put the IRP clutch in from day one and it was honestly a great bike. Never tossed a stator for us.

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wydopen
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wydopen 3/24/2022 5:01am
3/24/2022 5:01am
You sure it’s not the rear brake? When my son first got on his 65 the rear brake randomly overheated and locked up mid moto twice. Hasn’t happened since can’t figure out why it did it. I don’t think he was dragging it inadvertently, he rides on the balls of his feet and he wears size 3 boots.
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JWW85
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JWW85 3/24/2022 6:37am
3/24/2022 6:37am
wydopen wrote:
You sure it’s not the rear brake? When my son first got on his 65 the rear brake randomly overheated and locked up mid moto twice...
You sure it’s not the rear brake? When my son first got on his 65 the rear brake randomly overheated and locked up mid moto twice. Hasn’t happened since can’t figure out why it did it. I don’t think he was dragging it inadvertently, he rides on the balls of his feet and he wears size 3 boots.
That didn't even cross my mind, but when he first moved to it off the PW, I had to keep getting after him cause he'd drag the rear brake. Not sure if it was him being nervous about the power difference and thought we broke that habit. Could have been! Thanks for the idea and gives me something to watch for or look at if it happens again!
1
georgelwoolston 9/9/2024 5:36pm
9/9/2024 5:36pm
J-Mill wrote:
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started...
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started with the Nytro oil IRP sells then switched to B&W TrickShift.

Thinking about your issue, the clutch could’ve got so hot it expanded and locked it up. Seemed like after it sat or cooled down it free’d up.

Hey, new to this.. what made you shift to the B&W trick shift? I just picked up one of these bikes with an IRP clutch, but I’m in canada and IRP don’t ship liquids to Canada. - would you still recommend the B&W?

J-Mill
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J-Mill 9/9/2024 8:56pm
9/9/2024 8:56pm
J-Mill wrote:
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started...
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started with the Nytro oil IRP sells then switched to B&W TrickShift.

Thinking about your issue, the clutch could’ve got so hot it expanded and locked it up. Seemed like after it sat or cooled down it free’d up.
georgelwoolston wrote:
Hey, new to this.. what made you shift to the B&W trick shift? I just picked up one of these bikes with an IRP clutch, but...

Hey, new to this.. what made you shift to the B&W trick shift? I just picked up one of these bikes with an IRP clutch, but I’m in canada and IRP don’t ship liquids to Canada. - would you still recommend the B&W?

The oil from IRP is good but very expensive. I’m pretty sure it’s a clear ATF he sources from somewhere and labels it. I had heard about guys using the B&W and was able to get a gallon for the same price as a quart of the other stuff. Seemed to hold up to a lot of abuse, had good bite and ran cool as well. Everyone on 50’s in my area started using it and we didn’t see any oil related failures. 

1
georgelwoolston 9/10/2024 4:11am
9/10/2024 4:11am
J-Mill wrote:
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started...
The IRP clutch will remove 75% of the headaches. You can get 4-5 rides out of it before “needing” to change the oil too. We started with the Nytro oil IRP sells then switched to B&W TrickShift.

Thinking about your issue, the clutch could’ve got so hot it expanded and locked it up. Seemed like after it sat or cooled down it free’d up.
georgelwoolston wrote:
Hey, new to this.. what made you shift to the B&W trick shift? I just picked up one of these bikes with an IRP clutch, but...

Hey, new to this.. what made you shift to the B&W trick shift? I just picked up one of these bikes with an IRP clutch, but I’m in canada and IRP don’t ship liquids to Canada. - would you still recommend the B&W?

J-Mill wrote:
The oil from IRP is good but very expensive. I’m pretty sure it’s a clear ATF he sources from somewhere and labels it. I had heard...

The oil from IRP is good but very expensive. I’m pretty sure it’s a clear ATF he sources from somewhere and labels it. I had heard about guys using the B&W and was able to get a gallon for the same price as a quart of the other stuff. Seemed to hold up to a lot of abuse, had good bite and ran cool as well. Everyone on 50’s in my area started using it and we didn’t see any oil related failures. 

Thank you 🙏

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