New KTM 300 SX is going to be a great snow bike

[eric82930]

I would go with the sx 5 speed over the xc six speed as long as you don't have a recluse brain you should be able to gear it higher so 2nd is the power gear not 3rd and you'll have less gaps to overcome up or down. Only down side is higher 1st so you'll need to clutch skillfully to get unstuck from a trench without digging it deeper.

 

[JimBridger]

The new xc/xc-w transmission is the same now. Here is how it stacks up to the 22 and earlier XC/TX/EX transmission.

This transmission is lower geared throughout.

1st is 81%
2nd is 83%
3rd is 89%
4th is 88%
5th is 88%
6th is 91%

(% gear ratio of 19-22 xc/tx/ex transmissions)

Stock gearing on my 24 te300 is 13t/45t

 

[eric82930]

If that's true then gaps are wider than the old xc so the sx will be even better choice.

 

[JimBridger]

Here are the pre-23 ratios for the xc/ex/tx, vs the new 2024 ratios across the xc-w/xc/te/tx/ec/ex line up per manual. The sx will definitely be a better choice as far as transmission ratios go.

 

[MountainRider05]

Welp it’s official im going into uncharted waters and will be rocking a 24’ 300sx paired with my cmx120.. still going to keep the trusty 15 fe501 but i think this 300 from what i hear will be a blast to ride. So here is what im thinking for mods..
Tsp ecu or erm
High comp head
Xrt heat exchanger
131 deg tstat
Swapping my heated bars over
Selkirk intake
Pipe?? Not sure what yet.
Make my own engine blanket
Any other stuff i might be missing besides little things like pegs,hand guards, temp gauges etc.??.

 

[JimBridger]

Welp it’s official im going into uncharted waters and will be rocking a 24’ 300sx paired with my cmx120.. still going to keep the trusty 15 fe501 but i think this 300 from what i hear will be a blast to ride. So here is what im thinking for mods..
Tsp ecu or erm
High comp head
Xrt heat exchanger
131 deg tstat
Swapping my heated bars over
Selkirk intake
Pipe?? Not sure what yet.
Make my own engine blanket
Any other stuff i might be missing besides little things like pegs,hand guards, temp gauges etc.??.

Do these not come with a t-stat? I thought all the 2 strokes from ktm had a 158* stat stock? If so I highly recommend staying around 160* so it keeps the ecm, which now controls the powervalve, happy. Otherwise you'll be running rich just like the 4 strokes when they don't get up to temp.

I really liked my pro circuit platinum with shorty. I know everybody will argue but I say ceramic coat or wrap the pipe. We noticed a big difference between my buddies 300 performance vs mine with the wrapped pipe. His would spitter and sputter randomly until he wrapped his, then he was clean all the way through.

The head will take a m6x1.0 temp sensor in the coolant bleed screw hole to monitor temps.

I ran a c3 intake but removed my stock air box and made a "tent airbox" with most of my silencer inside my "tent airbox" for heat. Kept my filter clean even on deep blower days. I just used heat resistant vinyl.

Definitely run a good blanket.

Buy a stock xc tank so you get that extra 45 oz of fuel. Ha

Our group have been on 300 2 strokes since 2019 and love them. I went to a 450 and 3" and hate it. Wishing I had a 300sx and 2.5" 120 or 129.

 

[GlennRMK]

I have a 23 TC 250 and it does come with a 158 t stat. I verified on the dyno that the bike runs well and makes more power at lower coolant temps (110-130 F). A 130 t stat should be just fine. Not sure if you can easily fit a thermobob or C3 in there though.

I don't think a guy could go wrong with the PC pipe for snow use.

 

[NEWDUCK]

I just bought a PC with the r304 shorty. Will be testing it at the dunes this weekend. Ill report back with any noticeable power gains. Next id like to try the tsp set up but I think its worth waiting for the erm to come out

 

[steve250f@hotmail.com]

If anyone wants to play around with a build I do have an npp cone pipe from the last gen 300s ide part with. Built two bikes and just run the one. Probably can dig up a chart of what it gained

Mite be interested in pipe. Would it fit 2018tx 300 also looking for smart carb or lectron

 

[schwany31]

Run a CMX intake, its a velocity style with a wire that vibrates snow off the pre-filter. It works good. Running one on my 23 Xc 300

 

[JimBridger]

Remove your airbox and then make a "tent" airbox out of engine blanket material with the silencer inside for heat. You'll have a clean airbox even in bar deep rocky mountain powpow. That's how I run my 300 and 450 intakes.

 

[Sheetmetalfab]

Remove your airbox and then make a "tent" airbox out of engine blanket material with the silencer inside for heat. You'll have a clean airbox even in bar deep rocky mountain powpow. That's how I run my 300 and 450 intakes.

Interesting.

Do you have any pictures of your setup?

 

[JimBridger]

I run with my airbox cover on, using the c3 airbox tab. This is on my 450, but I set my 300 up the exact same other than a bit more material is needed by the silencer for the 300 vs the 450. I have velcro attached at the back so I just flip it up to check if it needs cleaned out, which it never does. It's important to cover your tunnel/subframe as well, as it keeps it from throwing snow directly onto the intake. I got this idea from Regan. He walked me through it messaging back and forth. He uses a neoprene material and does a bit different method, but the idea is the same and works great.

 

[JimBridger]

The tarp material is slick and allows snow to slide off easily. That mixed with the tarp covering the tunnel, the timbersled brake acts like a pyramid almost directly under the airbox and the snow slides to the outside edges and back out of the "tent". Best part is all that material and zip ties only cost me about $20.

 

[Archie]

Reviving this thread a bit. I’ve been running a 2018 300xc with a 2018 Aro 120 since new, switching back and forth every season, over 400 hours now on the bike. I keep telling myself this is the last season I’m going to run this setup and finally get a dedicated 450 snowbike for next year, but I agree with a lot of the comments here. The 300’s have their place, but I do have more fun on mine than my buddies 450’s, probably just preference.

MountainRider05, how was the first season on the new bike?

 

[GlennRMK]

Anyone else notice the gear ratio change for the 25 250 XC? It now has a close ratio 6 speed. I think this would be the perfect snowbike trans. Has the same 6th as the XC-W but with almost identical ratios to the SX on 1-5. Its odd that the 300 does not have the same transmission, but you could put the 300 top end on it. Cheaper to swap cylinders than transmissions.

 

[G-Force]

Archie, depending where you're at, have I got a setup for you

 

[NEWDUCK]

Anyone else notice the gear ratio change for the 25 250 XC? It now has a close ratio 6 speed. I think this would be the perfect snowbike trans. Has the same 6th as the XC-W but with almost identical ratios to the SX on 1-5. Its odd that the 300 does not have the same transmission, but you could put the 300 top end on it. Cheaper to swap cylinders than transmissions.

If They made that tranny in the 2025 300sx it would be gold! Thanks for posting that chart.

 

[Archie]

Archie, depending where you're at, have I got a setup for you

I’m good for this season, but what have you got? I’m just outside of Red Deer.

 

[CATSLEDMAN1]

Could not face another winter without some mods...... moved my RIOT kit forward more on the 300sx, track paddles just clear the lower suspension mounts on the back of the KTM frame cross bar. can't decide how big an improvement it is, never did use the RIOT kit stock, moved it ahead day I got it. But now I removed two full links in my drive chain, and could do two more if I notched the track, right now I don't see the value in it. Have to add some more dampening to the shocks, springs ok, but need a little more dampening. Overall from stock Riot I have moved the kit forward about 2.5 inches. So far nice light early snow and the sx likes to climb right on top, more or less than last year ........... got to ride it some more to really figure it out.