Carbureted vs Fuel-Injected 300 Two Stroke

How would you describe riding a 350 SFX vs. a 300 SX? Power, weight, feel, effort required, or whatever seems relevant.

Just read the write up….  Very well done…..I have a 23 300SX and a 24 350sfx… ride both regularly…I have the 300 setup for gncc type riding but have plenty of Mx hrs on it…. I love both of these bikes, for me, its a little easier/ physically to ride the 350 at most tracks, move forgiving… but in the sand I think I am faster on the 300…if you are in good physical shape and are a more aggressive rider the 300 is very effective….I just bought a 25 300 leftover for 8300.00 out the door…. My 23 has close to 150hrs now and has been one of the best bikes I have ever owned. After putting 40 hrs on it stock, I had the ecu tuned by Jon Ross at TPI tuning….it lugs great and it has a very good top end over rev…pretty much 3rd gear everywhere accept the tightest of turns….the fuel injection has been perfect on this 300, I have had many carbed 300”s and the jetting was always a work in progress but never perfect, I don’t miss playing with jetting on a modern bike…..

I mean yea.  Sorta what I feel with my butt too.

Should give the 250 tbi bikes a go too.

Sounds like the KTM is a Vets dream and the Beta is for a Factory Pro jockey. Overall great review and not healthy for my wallet. 

I am not a two stroke guy, but I have ridden the latest KTM300XC and liked it. Having said that, I would not buy a fuel injected two stroke. If I were buyinhg a two stroke, I would be looking at Beta and Sherco. Not too interested in having a flashback to 2005, so will pass on the Yamaha

Loved this video! I own a 25 300sx and the way you described the lack of vibration, feel coming out of corners and lugability all resonates with why I love the bike.  It’s so light and flickable everywhere but has tons of linear usable power.  Anybody afraid of the TBI needs to take their tin foil hat off and ride one.  The power delivery is amazing and it runs perfect every time 

How many top ends did you do by 150 hours? I know the manual says every 15 and im doing my first one at 23 hours 

Please do this comparison when the Beta 350 hits the streets. 

Nice review!

Great work, interested for the upcoming yz250 vs Ktm 300 and to hear others opinions. I recently switch from 8 years on Ktm 250/300’s to a 25 yz250 and imo the yz is not even close to the Ktm’s as a race bike. As a fun play bike it’s rad but good god it vibrates and is much harder to ride than the ktm 300. Eventually Im gonna 300 the yz and balance the crank and I could see it closing the gap. 

Do yourself a favor and keep the money in your pocket. 25 hour Piston, is straight insanity, unless your racing MX in sand and are ringing it out the whole race !! 
I’ve put 150 hours on each of my ‘23 XC300’s (Two different bikes) the pistons still looked great when I replaced them. They were noticeable after a rebuild, but not worth the cost of replacing the piston that early. 

DO NOT put a piston in it until at least 100 hours. Yes, I’m serious ! Unless you’ve gotten dirt past your air filter or don’t change your oil every 10 hours, you’d be wasting your money. 

I did probably 15-16 top ends on my Ktm from 2017-2024 all at 50 hours and everything always looked good. That was pure moto, couple sand dune trips and I feel like I ride them hard. Anything under 50 hour imo is a waste of money.

I have 300 hours on a 350XCF and now ive put 30 hours on my 24 300XC and I would say they are both good for certain situations. 

If you are doing more moto style riding or grass track flowy stuff I think the 350 is a bit easier to ride or if its slippery but pretty open like wet red clay over hard pack its a bit easier to ride. 

When it gets tighter and rougher the 300 to me feels like less work and is easier to put where I want it, you can almost  have two bikes depending on what gear you are in you can scream it with insane amount of power or lug it a bit more. 

As others have stated…. I did my top end at 100hrs….and I probably could have just re-ringed it…everything looked great. The powervalves needed a service but were still operating smoothly. I also replaced the clutch plates and rubber hub dampers. From experience of owning several Xc300”s in the past, if routine maintenance is done, I.E. clean filters, good quality fuel & premix oil, easy 100hrs on top ends…I”m a Vet/+50 A Mx rider that rides a good amount of deep sand where the engine is working hard….if I were a single track non rev guy, I would go 150hrs on a top end….I know some guys have reported failures with these newer FI bikes but mine has been nothing short of bulletproof….

I was a solid yamaha guy from 99-2008 several YZ250”s, great bikes,  but my last 2, I could not make a transmission last a season. In My riding group many of us who were on the Yz”s, had to replace several gears and all the shift forks on our bikes …now we did have some really rough, whooped sand tracks we rode regularly, but I ride those same tracks on my ktm”s and have never had a transmission failure on my KTM”s…the clutches, front brakes and bottom end durability of KTm”s has me sold….

I”m 100% 2T guy when riding Gncc/ woods tracks…I have tried 4T”s in the woods, just don’t like them. I have an Xc tank, Cycra hand guards, fmf gnarly pipe, fastway kickstand and 1 extra tooth on rear of my 300SX, instant woods weapon for much less than buying an XC model…

These things last 100 hours easily. I replaced the piston in my 300 at 106.9 hours and the ring end gap was 0.014"...the new piston kit had an end gap of 0.015" right outta the box. My piston was still well within spec. I have a few friends that have replaced pistons at 200 hours, they probably could have gotten away with just rings.

If no dirt has gotten by your air filter, leave it together.

I would be more concerned with the cast piston coming apart due to sustained high roms on the track. Ktm engineers seem to think their 4t pistons last 3x as long as their 2t pistons. Whether people realize it or not a woods bike is way easier on the piston than a track bike. 

I definitely agree with the video’s comments about the Beta 300 RX’s power. If I had a lot of tracks nearby that would allow me to hold it wide open for a stretch, it would probably be a deal changer for me, but it seems that the current trend in mx practice track building in my area is to design tracks so the speeds are reduced by making everything, soft, rutted, jump-turn, jump-turn. You have to accelerate hard out of the corner even for little jumps because they laid down the jump faces so you don’t get any serious air. Low to mid engine power is going to work well in this type of situation.  It is not that there is no top end pull whatsoever, but I wouldn’t be so confident on winning a high speed drag race with other bikes.

In difference to the video’s experience with the suspension, IMHO, I feel it is way too stiff.. especially the rear shock with some silly heavy rebound dampening.   I weigh 194 lbs and since the shock barely moves when you push down on it, I am having to back way off the shock LS compression and rebound. So if the professional testers are having to add more compression and rebound dampening, I can only wonder if we even have the same shock or if mine has the wrong valving from the factory! I believe this is not a matter of personal taste or riding ability.. it is that far off from usable for just about any rider IMHO... at least the shock on my bike. This is just tried and true Kayaba suspension so I was wondering what might be different besides the valving to screw it up. That is when I noticed the baby suspension knuckle. It is quite small compared to other mx bikes and the leverage ratio must not be as great on the shock. It is truly a small knuckle on the shock linkage.. I don't think it has even reached puberty yet.

I had serious trouble shifting and finding the rear brake lever when standing because they are under the unusually wide radiator shrouds. I had to turn my foot in to reach both pedals.  However, I found some good solutions that put the levers in a much more accommodating position, and to me it means there was obvious recognition of this problem. Beta, Moose Racing and Hammerhead all have shift levers (all made by Hammerhead) that move the pedal tip way out from the engine case, as well as making it longer.  The same exits for the brake pedal with alternative lever shapes and bigger pedal tips. It is a night and day difference. Here is a picture of the new shift lever.. very easy to access now to stay in the right gear which is some important to keep a 2 stroke “on the pipe”.

I also had to get rid of the hard Beta seat foam, and Guts Racing soft foam was just the ticket. In now feels like an oem seat like on my Honda’s and Yamaha’s, so I don’t have the feeling of sitting on top of the bike.

I also found the Beta front brake quite grabby at lower speeds. I don’t need breaking power as I am not that fast, but I want more progressive modulation, not a light switch. The Moto-Master MXC billet front brake caliper is the solution and it is truly a piece of mechanical art. It is a bolt-on part with no adapter’s needed. Check out this beauty!

I ended up having to a lot more work on the bike than I anticipated to get me comfortable.  A YZ250 would be comfortable for me right out of the crate.. not so here, but hopefully all the mods will correct the little complaints so I have a cool and unique bike in the end.