What two stroke 50s are best

Motoguy89
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103
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7/20/2024
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Syracuse , NY US
9/14/2025 12:59pm
hangingout wrote:

https://www.ktm-parts.ca/ktm-motorcycle/assignment_spare_parts/45412955044S

Look up part number 45412955044S 

Had one for a Ktm 50, worked great.

Also fits the E-5 models.

I’ve came across this before but what the heck is it?? Brackets for the frame? This will make a full sized 50 the height of a mini 50?

9/14/2025 2:00pm
hangingout wrote:

https://www.ktm-parts.ca/ktm-motorcycle/assignment_spare_parts/45412955044S

Look up part number 45412955044S 

Had one for a Ktm 50, worked great.

Also fits the E-5 models.

Motoguy89 wrote:
I’ve came across this before but what the heck is it?? Brackets for the frame? This will make a full sized 50 the height of a...

I’ve came across this before but what the heck is it?? Brackets for the frame? This will make a full sized 50 the height of a mini 50?

This is what my kit came with. My suspension guy installed it and was pretty much same height as a mini.

IMG 2533 3.jpeg?VersionId=vVhh37LbGKYTuMPC3df866CItYgJO
1
9/14/2025 2:04pm Edited Date/Time 9/14/2025 2:05pm

Honda Elsinore MR50. But that was back in 1974. Wow how the little bikes have come along way.  It was so much faster than a Z50 or CT70. And I bet these little ones are so much faster than that was.  

mxfolife732
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76
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10/15/2019
Location
Washington, PA US
9/14/2025 5:24pm

Ended up buying a gas Gas got a really good deal on a leftover is what it is. I’ll see how it holds up and how he does on it. He’s too small  65 at the moment. since I’ll be changing the oil a lot does anybody have any recommendations other than motorex that would be cheaper and works well? 

1

The Shop

9/14/2025 7:46pm

I’ve had nothing but good luck with the KTM mini. Use a good synthetic ATF after every ride, sometimes between motos if it’s hot or he’s riding hard. He just moved up to a 21’ SX50 factory edition I picked up with low hours (first ride today was awesome).  Hopefully with frequent oil changes, good gas, and overall maintenance it too will be just as good as the mini. 

Side note, what fuel do all you mini dads run in a stock 50?  I cannot get ethanol free fuel here from a pump. 

dadofagun
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1990
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Satan's Hollow, OK US
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9/14/2025 8:27pm
Motoguy89 wrote:
Man are these 50s really that bad??? My son is 5 and has been on a pw for couple years now and I was thinking about...

Man are these 50s really that bad??? My son is 5 and has been on a pw for couple years now and I was thinking about getting him a ktm sx50 mini. Unfortunately ktm doesn’t make them anymore and they are difficult to find… a full-size 50 would be too big of a jump size wise, it would be awesome if you could lower a full size 50 to roughly the same height as the mini. I have heard there are kits you can buy to have the suspension lowered but can’t find any good information on it… is this actually a thing? The E bikes are cool and all, and we started him out on a Stacyc, but this kid loves his gas engine so I know he wouldn’t be thrilled on the electric 50.

Yes, fast 50's are that bad.  They, in my opinion, are really too much on parents, plus the little guys and gals who are excited as can be to ride well past us parents energy level.....  until it breaks.  And THEY ALL BREAK......CONSTANTLY.  Jr is sitting over here discouraged, you are pissed, Mom is pissed because this new family hobby is straining the shit out of the household budget, and half the time, the damn thing isn't running.  The fun of Moto isn't as fun anymore, and you just have gotten your feet wet.......

Run as far away from these bastards as fast as you can.  I cannot speak on the whole electric pee wee thing, but from comments on here, its sounding like it could be a good thing to look into....  Regardless, if you wanna have fun, not go broke, and keep a happy marriage if you are married, I strongly advise you to stay away from fast 50's.......  Unless your bank account is bottomless.

I never in my life felt so guilty, as our first couple races on the 65 full time.  Come off the track, Spokes, filter, chain.  Add gas.  Done.  And the bastard started everytime.  I could enjoy a day at the track with the family......  and not be killing ourselves keeping our then $8000 worth of pee wee shit alive for one entire Sunday.  It was wonderful.....  And Momma was happy too.

That alone is worth more than anything.......

6
9/14/2025 10:09pm
dadofagun wrote:
Yes, fast 50's are that bad.  They, in my opinion, are really too much on parents, plus the little guys and gals who are excited as...

Yes, fast 50's are that bad.  They, in my opinion, are really too much on parents, plus the little guys and gals who are excited as can be to ride well past us parents energy level.....  until it breaks.  And THEY ALL BREAK......CONSTANTLY.  Jr is sitting over here discouraged, you are pissed, Mom is pissed because this new family hobby is straining the shit out of the household budget, and half the time, the damn thing isn't running.  The fun of Moto isn't as fun anymore, and you just have gotten your feet wet.......

Run as far away from these bastards as fast as you can.  I cannot speak on the whole electric pee wee thing, but from comments on here, its sounding like it could be a good thing to look into....  Regardless, if you wanna have fun, not go broke, and keep a happy marriage if you are married, I strongly advise you to stay away from fast 50's.......  Unless your bank account is bottomless.

I never in my life felt so guilty, as our first couple races on the 65 full time.  Come off the track, Spokes, filter, chain.  Add gas.  Done.  And the bastard started everytime.  I could enjoy a day at the track with the family......  and not be killing ourselves keeping our then $8000 worth of pee wee shit alive for one entire Sunday.  It was wonderful.....  And Momma was happy too.

That alone is worth more than anything.......

this is the reason I have an old DS80 to teach my son a clutch before he goes to a YZ65,  I dont like working on bikes that much to have a ktm50sx. 

2
9/15/2025 6:22am

Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range get the 50 FWE. They aren’t that bad at all, buy a new one and maintain it properly. You won’t have any problems.

This is current information, not from years ago..

2
vdrsnk04
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2023
Joined
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Location
IL US
9/15/2025 7:48am
Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range...

Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range get the 50 FWE. They aren’t that bad at all, buy a new one and maintain it properly. You won’t have any problems.

This is current information, not from years ago..

That’s the problem with all 50’s though including Cobra. The “maintain it properly” statement is the issue, proper maintenance on a 50 is a pain in the butt and nobody has fun with it. That is current information from a current mini dad among many others in here unfortunately.

1
9/15/2025 8:04am

Had a 2023 KTM 50SX bought new, went through my daughter, then son and sold with 90hrs. Outside of general maintenance (top end every 40hrs), only went through a left side crank seal. Never went through a stator or clutch (measured in spec)... Not sure why guys have so many problems with these? Jet properly, set the clutch and ride. Adjust clutch to rider's skill. We started at 4 clicks on each kid and ended up around 10-11 to get the required stall RPM per manual when they could ride faster.

mxfolife732
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Location
Washington, PA US
9/15/2025 9:19am
Had a 2023 KTM 50SX bought new, went through my daughter, then son and sold with 90hrs. Outside of general maintenance (top end every 40hrs), only...

Had a 2023 KTM 50SX bought new, went through my daughter, then son and sold with 90hrs. Outside of general maintenance (top end every 40hrs), only went through a left side crank seal. Never went through a stator or clutch (measured in spec)... Not sure why guys have so many problems with these? Jet properly, set the clutch and ride. Adjust clutch to rider's skill. We started at 4 clicks on each kid and ended up around 10-11 to get the required stall RPM per manual when they could ride faster.

Appreciate this response.. when I change the oil I was going to put the clutch at about 4 clicks… did you run motorex or another brand for transmission fluid? 

30minmotos
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Rising Sun , MD US
9/15/2025 9:33am

I never had a fast 50 no kiddos there yet, but I bet the track conditions play a huge role in maintenance levels. Hard pack no elevation vs deeply ripped tracks with large hills etc.

9/15/2025 9:37am
Appreciate this response.. when I change the oil I was going to put the clutch at about 4 clicks… did you run motorex or another brand...

Appreciate this response.. when I change the oil I was going to put the clutch at about 4 clicks… did you run motorex or another brand for transmission fluid? 

I ran Motorex Dexron III for a bit but then experimented with others and found the Motorex Dexron III is Dexron III "Type H" spec. I ended up running ACDelco Gold 10-9240 (88865544) Type III (H) and found it was as good, if not better than the Motorex at heat resistance and wear material on the drain plug. I found 1 of the worst was Valvoline Dex/Merc. I never tried the B&M Trick Shift that "everyone" seems to run because the tech specs on both were too different for me to feel comfortable with.

EAmato88
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Egg Harbor City, NJ US
9/15/2025 9:38am

theyre both junk. KTM is a bigger piece of junk. Choose your junk wisely

2
9/15/2025 10:23am Edited Date/Time 9/15/2025 10:24am
Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range...

Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range get the 50 FWE. They aren’t that bad at all, buy a new one and maintain it properly. You won’t have any problems.

This is current information, not from years ago..

vdrsnk04 wrote:
That’s the problem with all 50’s though including Cobra. The “maintain it properly” statement is the issue, proper maintenance on a 50 is a pain in...

That’s the problem with all 50’s though including Cobra. The “maintain it properly” statement is the issue, proper maintenance on a 50 is a pain in the butt and nobody has fun with it. That is current information from a current mini dad among many others in here unfortunately.

I just really don’t have any problems to be honest. Change out the air filter at the end of a ride or race day, change out the clutch oil at the end of a weekend, check the CFD every few rides or if it’s a brand new build then after 30 mins. Adjust as necessary. Keep it clean, WD the pipe and chain, adjust the chain. It all becomes very routine after a while. You probably already do, but get the yellow carb cover so you can pull the air boot/filter and wash safely.

Now that I don’t run c50 fuel anymore (switched to sx2 renegade 50:1 maxima k2) then the carb is remarkably trouble free when I used to have a spare at all times. Depending on how competitive you are have one of the many engine builders refresh the top end, clutch, CFD, and carb between 10 and 25 hours. 

I think people lack the basic maintenance, end up having problems, then tear it down themselves and end up not doing that properly as well. Then, it’s a circle of constant issues.

I’ll personally miss 50’s come next year. Sad

3
Mx391
Posts
311
Joined
10/25/2017
Location
y, TN US
9/15/2025 10:50am
Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range...

Cobra is the best with the most dealer support and parts availability by far. 4 to 6 yrs get the 50 junior. 7 to 8 range get the 50 FWE. They aren’t that bad at all, buy a new one and maintain it properly. You won’t have any problems.

This is current information, not from years ago..

vdrsnk04 wrote:
That’s the problem with all 50’s though including Cobra. The “maintain it properly” statement is the issue, proper maintenance on a 50 is a pain in...

That’s the problem with all 50’s though including Cobra. The “maintain it properly” statement is the issue, proper maintenance on a 50 is a pain in the butt and nobody has fun with it. That is current information from a current mini dad among many others in here unfortunately.

I just really don’t have any problems to be honest. Change out the air filter at the end of a ride or race day, change out...

I just really don’t have any problems to be honest. Change out the air filter at the end of a ride or race day, change out the clutch oil at the end of a weekend, check the CFD every few rides or if it’s a brand new build then after 30 mins. Adjust as necessary. Keep it clean, WD the pipe and chain, adjust the chain. It all becomes very routine after a while. You probably already do, but get the yellow carb cover so you can pull the air boot/filter and wash safely.

Now that I don’t run c50 fuel anymore (switched to sx2 renegade 50:1 maxima k2) then the carb is remarkably trouble free when I used to have a spare at all times. Depending on how competitive you are have one of the many engine builders refresh the top end, clutch, CFD, and carb between 10 and 25 hours. 

I think people lack the basic maintenance, end up having problems, then tear it down themselves and end up not doing that properly as well. Then, it’s a circle of constant issues.

I’ll personally miss 50’s come next year. Sad

I agree with you. Cobra 50s are the best and not much issue if you change the oil and keep filter clean. Most these guys talking from experience years ago or from here say

1
dadofagun
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1990
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3/28/2015
Location
Satan's Hollow, OK US
Fantasy
9/15/2025 2:15pm
EAmato88 wrote:

theyre both junk. KTM is a bigger piece of junk. Choose your junk wisely

Back in the day, we were KTM, and I was talking to a Cobra Dad on the line one Saturday night.  He asked how I liked the KTM, I said they are crap.  I asked him how he liked his Cobra, he said it's crap.  Then he said, but we ride faster crap!  We both laughed hard because he was so spot on.  He also said Santa was bringing an new 65 that year so he could save his marriage, followed by more laughs......

2

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