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

[portgrinder]

Is there a programable tuner for the new 300s yet? Would need one to get me interested in tinkering around. No reason the std stuff that worked on the carb 300 shouldn’t work on the new one.

Interesting your comments on the brc. I never got that interested due to price and lack of a well developed powervalve. With some tinkering you can really get the torque flat on a 300 and that would really make the brc good by what you are saying.

 

[NEWDUCK]

Is there a programable tuner for the new 300s yet? Would need one to get me interested in tinkering around. No reason the std stuff that worked on the carb 300 shouldn’t work on the new one.

Interesting your comments on the brc. I never got that interested due to price and lack of a well developed powervalve. With some tinkering you can really get the torque flat on a 300 and that would really make the brc good by what you are saying.

TSP should have a programable tuner out soon. JD has the piggy back style out already.

 

[teal_210]

I sure can't say what the internal engine differences are unless I had both on the bench. Been told by KTM mechanic its different, and part numbers are different, time will tell. What is different riding this model is the low to high very quick throttle response, can put you on your head in the dirt, I think that feature of the engine will make some snow bikers happy. The transition to snow bike is under way, mostly planning right now, made three head exchangers for the two strokes in the riding group, heated bars and thermostats and on and on will take until the snow flies.

Part numbers for the cylinder, piston and head are all the same between the SX and the XC, at least according to the online parts diagrams.

 

[byeatts]

Yeah i rode a 2023 300XC also.

Impressive at all rpm ranges.

Really shines on top compared to any other 2 stroke I’ve ridden.

Long smooth legs.

Well the new TBI has too high of compression and ignition timing to pull RPM,s, on dyno , too high of compression and tight squish limits the rev capability's, it made more power off the bottom and mids than the TPI. It made 1.5 hp more however a downside to this higher compression aggressive timing build load of low power then it falls on its face about 1000 RPM sooner than the TPI engine . , Snow bikes IMO benefit from RPM over HP since rpm is what ramps up track speed. Think of a diesel motor making gobs of low power but wont have any over rev and no legs. TBI is a great motor however it lacks the RPM.s and falls off at 6800 rpm which is very low in comparison to the well tuned 450 running 11500-11800 rpm. we did run fully modded 300,s against the tuned 450 and riders could not follow deep steep climbs even poaching since the 2 T did not have the torque to hold the gear.. The rider who was bragging his 300,s is soo fast had to meet up with the group by finding a mellow route up. These are factual finding while on the mt. The over rev of the 450 especially the KTM , Husky engines is what makes a really strong snowbike, This is why i dislike the 500,s they also sign off very early in the RPM range., They were also on the ride with thier fully modded 500 XCW loads of low end but that does not build track speed .under load its counter productive to continual shift to try to stay off the rev limiter .

 

[suva]

I'd like to interject a few things:

-BDSP is not a trustworthy resource and he's also testing compression at close to sea level.

-Even though I have been riding a 2 stroke for the last few seasons and I prefer riding it over a 4 stroke I have no illusions about it having better performance than a 450 except in very specific circumstances.

-You have to be a good enough rider to keep a 2 stroke in the power for it to be possible to keep a 450 in sight

-While peak rpms are useful having a wide spread of power is a much bigger deal.

-My TBI 300 is easier to keep in the power than my carbed or TPI bike are, I think this is almost entirely due to the electric power valve. This is the advantage of the new 300. Will this make it perform better than a 450 on the snow? I seriously doubt it. But I just ride snowbikes for fun and my lesser performing 300/120 has never failed to get me to where any 450 3" I've ridden with has gone, I just have to ride harder..... Which makes it more fun.

 

[byeatts]

I'd like to interject a few things:

-BDSP is not a trustworthy resource and he's also testing compression at close to sea level.

-Even though I have been riding a 2 stroke for the last few seasons and I prefer riding it over a 4 stroke I have no illusions about it having better performance than a 450 except in very specific circumstances.

-You have to be a good enough rider to keep a 2 stroke in the power for it to be possible to keep a 450 in sight

-While peak rpms are useful having a wide spread of power is a much bigger deal.

-My TBI 300 is easier to keep in the power than my carbed or TPI bike are, I think this is almost entirely due to the electric power valve. This is the advantage of the new 300. Will this make it perform better than a 450 on the snow? I seriously doubt it. But I just ride snowbikes for fun and my lesser performing 300/120 has never failed to get me to where any 450 3" I've ridden with has gone, I just have to ride harder..... Which makes it more fun.

The question is which works best as a snowbike, Thoses who have a 300 will tell ewe it rocks , thoses who have a 300 and a well setup 450 and can ride either will take a 450 every time simply becuase it will out perform, Those who switch back to dirt for summer will find 300 is the best choice.

 

[eric82930]

So the Dyno chart in the video is not what the new bike feels like at all. my personal bike is a 250sx and I usually hate the 300tpi but was impressed with the stock tbi doing huge hill climbs in dirt at 7k altitude. I'll have to trust my own test over his sea level Dyno for now. Either way if the squish is too tight and timing too high that's so easy to fix I can't imagine ktm won't reflash them or update the head. Duh.
But if you have to out climb your buddies in snow don't get a 2 stroke. Go impress us on the big hill with the 450. The high mark does feel nice sometimes even if you have to wear ear plugs and warm your bike up with your truck exhaust to get it to start sometimes.

 

[suva]

The question is which works best as a snowbike, Thoses who have a 300 will tell ewe it rocks , thoses who have a 300 and a well setup 450 and can ride either will take a 450 every time simply becuase it will out perform, Those who switch back to dirt for summer will find 300 is the best choice.

My 300 is a dedicated snow bike, as were the 450s I had previously. I was planning on going back to a 450 until I rode one again. No thanks, I like the 300 better. I just like riding it more.

 

[GlennRMK]

Well the new TBI has too high of compression and ignition timing to pull RPM,s, on dyno , too high of compression and tight squish limits the rev capability's, it made more power off the bottom and mids than the TPI. It made 1.5 hp more however a downside to this higher compression aggressive timing build load of low power then it falls on its face about 1000 RPM sooner than the TPI engine . , Snow bikes IMO benefit from RPM over HP since rpm is what ramps up track speed. Think of a diesel motor making gobs of low power but wont have any over rev and no legs. TBI is a great motor however it lacks the RPM.s and falls off at 6800 rpm which is very low in comparison to the well tuned 450 running 11500-11800 rpm. we did run fully modded 300,s against the tuned 450 and riders could not follow deep steep climbs even poaching since the 2 T did not have the torque to hold the gear.. The rider who was bragging his 300,s is soo fast had to meet up with the group by finding a mellow route up. These are factual finding while on the mt. The over rev of the 450 especially the KTM , Husky engines is what makes a really strong snowbike, This is why i dislike the 500,s they also sign off very early in the RPM range., They were also on the ride with thier fully modded 500 XCW loads of low end but that does not build track speed .under load its counter productive to continual shift to try to stay off the rev limiter .

I totally disagree. Although our dyno is at 4500 ft (power is corrected but running a knobby tire) but from what I've seen the TBI stomps on the TPI, especially on top. The TBIs I've done made more power than any stock carb or TPI bike. Dyno'd a 23 300 XC and my personal 23 TC 250. Way more overrev vs 18 250 XC-W carb (SX head and CDI).

23 300 XC



23 TC 250 vs 20 250 XC


23 TC 250 with FMF Gnarly


07 YZ 250 PC pipe vs 23 TC 250


18 vs 23

 

[schwany31]

Coming back into this......The fuel consumption on my TBI XC 300 was very comparable to a 22 yz450f with the exact same kit.

Power wise, iv been on multiple different 300s and 450s, the new TBI feels like an absolutely ripper IMO. I ride with a 22 yz450f with the same kit (120 cmx) he is running a tuner other wise we are both stock. No dout on the big and steep climbs the 450f definitely seemed to do better and easier to ride, but man my TBI would wheelie easier (Similar setups) and was just a blast to ride. The wheelies would sometime become an issue on a climb. (had to really ride the thing, on the tank, shifting your body weight etc) There would be times on the deep and steep spots id occasionally poach the 4 stroke tracks....i think what it comes down to it the fun factor....1 love 2 strokes. 4 strokes sound dumb.....

1 thing i can say the TBI has been the best 2 stroke snow bike iv ridden and it was STOCK....past bikes consisted of a stroker YZ300 (Prob made the most power) and a 2015 xc 300, TMR ported for snow bike....the TBI just seemed to work. easy to get into the power, good over rev. and it was stock, cant wait to tune and throw a pipe on it.....

 

[eric82930]

That last Dyno is much closer to what it feels like seat of pants

 

[GlennRMK]

IMO both the YZ and older carb KTMs hit harder in the mid but the TBI is pretty smooth and pulls harder on top.

 

[byeatts]

I totally disagree. Although our dyno is at 4500 ft (power is corrected but running a knobby tire) but from what I've seen the TBI stomps on the TPI, especially on top. The TBIs I've done made more power than any stock carb or TPI bike. Dyno'd a 23 300 XC and my personal 23 TC 250. Way more overrev vs 18 250 XC-W carb (SX head and CDI).

23 300 XC

View attachment 406284

23 TC 250 vs 20 250 XC
View attachment 406285

23 TC 250 with FMF Gnarly
View attachment 406287

07 YZ 250 PC pipe vs 23 TC 250
View attachment 406286

18 vs 23

View attachment 406288

Ewe guys can justify ewer choice all day long , I,m a KTM shop and have carbed, TPI TBI 300,s SX 450 and 500,s all here built snowbikes , Plain and simple the 300 is a great motor but it Will not keep up with the 450 due to the lack of RPM, We run them all the time side by side. Ride what ewe want and justify what you currently have thats the pattern here, the 300 is a better choice if you switch it back to dirt, The 450 is a better choice for a dedicated snow bike assuming its tuned correctly.

 

[ravenous]

Ewe guys can justify ewer choice all day long , I,m a KTM shop and have carbed, TPI TBI 300,s SX 450 and 500,s all here built snowbikes , Plain and simple the 300 is a great motor but it Will not keep up with the 450 due to the lack of RPM, We run them all the time side by side. Ride what ewe want and justify what you currently have thats the pattern here, the 300 is a better choice if you switch it back to dirt, The 450 is a better choice for a dedicated snow bike assuming its tuned correctly.

I love 300's with wheels! They are amazing. My 450's are better in the snow. Hands down. I find it interesting that some guys claim they like the challenge of a 300 on the snow. I love challenges too. But why not pick the best bike you can for a snowbike? If you really love challenges why not ride a 125 2-stroke on the snow? Or maybe drive a school bus in the desert in a SCORE race? Or a600cc sport bike in a trials comp? Anything is possible!

 

[GlennRMK]

Ewe guys can justify ewer choice all day long , I,m a KTM shop and have carbed, TPI TBI 300,s SX 450 and 500,s all here built snowbikes , Plain and simple the 300 is a great motor but it Will not keep up with the 450 due to the lack of RPM, We run them all the time side by side. Ride what ewe want and justify what you currently have thats the pattern here, the 300 is a better choice if you switch it back to dirt, The 450 is a better choice for a dedicated snow bike assuming its tuned correctly.

I was saying I don't agree with the Best Dual Sports guy at all. This guy is an odd duck. I will say I recently rode a 22 300 XC with his TBI conversion and remap and it ran flawless. Way better than any TPI I've ever ridden.

I totally agree that a 450 MX bike is best for snowbiking.

I'm actually a 250 2T guy (I've had 3 300s and just like 250 better) for dirt. IMO you just can't beat a 250/300 for single track.

It is a shame that a 450 MX bike absolutely makes the worst possible trail bike. They suck on tight mountain trails. Absolutely hate my 19 Husky 450 for dirt use.

I rode a 300 XC on snow for a season, and it works fine, its just not as good as the 450.

 

[eric82930]

Jeesh, riding a 125 snow bike would not be an enjoyable challenge. They only have 30hp. My 300s have always been close to 60hp. So I guess it's possible up until now that almost everyone that is commenting about two strokes in the snow has some bias based on the dismal performance of stock 300s from the past. Honestly I don't know if I would ride one stock either but I have totally enjoyed the 250sx bone stock. They are very enjoyable and not much more of a challenge really if you know how to ride them. If I was racing for the high mark they would be a bit behind but they will get there eventually. It's great to have both options finally close enough peak hp to really not make that much difference in the real world.

 

[byeatts]

I was saying I don't agree with the Best Dual Sports guy at all. This guy is an odd duck. I will say I recently rode a 22 300 XC with his TBI conversion and remap and it ran flawless. Way better than any TPI I've ever ridden.

I totally agree that a 450 MX bike is best for snowbiking.

I'm actually a 250 2T guy (I've had 3 300s and just like 250 better) for dirt. IMO you just can't beat a 250/300 for single track.

It is a shame that a 450 MX bike absolutely makes the worst possible trail bike. They suck on tight mountain trails. Absolutely hate my 19 Husky 450 for dirt use.

I rode a 300 XC on snow for a season, and it works fine, its just not as good as the 450.

Also i should mention the 350xc was almost identical in performance with the TBI both with yeti 129 ss kits. although the 300 makes a tad more hP the 4T rpm more than made up for it and they are too close to call.

 

[JimBridger]

I own both. 2 strokes are just funner. The 450 on the 3" track does well, but the 300 on a 2.5" is significantly more nimble. I like tree banging and the 2 strokes are funner for that. Deep days the 450 and 3" are nice, but kind of boring in comparison. My 21 300 with the tsp irk, 15.5:1 head, and pro circuit exhaust has a bit of an edge over the stock tbi, but with a few mods, the tbi should stomp my bike. The 300 sx may be the ultimate snowbike for guys under 200 lbs. I'm excited to see more of them on the hill this season.

 

[portgrinder]

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

 

[GlennRMK]

How did the TBIs work last year?

Thoughts on SX trans vs XC? XC is a wide ratio now, so I feel like that may be a downgrade other than more top speed than the 5 speed.