4 stroke vs 2 stroke

creature654 wrote:

I mean every 2 stroke has its bog...at the same time every 4 stroke drops a valve

Alex.434 wrote:

[b]40 years old C (West Coast) to B (East Coast) MX rider. B off-road / enduro racer. Sporadic Moto-journalist and photo shoot talent. Expert level roadracing...

40 years old
C (West Coast) to B (East Coast) MX rider.
B off-road / enduro racer.
Sporadic Moto-journalist and photo shoot talent.
Expert level roadracing and Supermoto racer.
Current MX bike: Husqvarna TC250
Other bikes: KTM 525 EXC, YZ250F Supermoto, RMZ450 Supermoto, Yamaha R1 Superbike, Alta MX, Alta EX

Personally I prefer to ride motocross on 250 2st's over 250F's and 450F's. When it comes to riding 4st's I've spent a lot of time on 250F's, so am damn comfortable on one of those out on the track, and always liked 250F's over 450F's. Though recently (last Thursday) I spent an entire day on a 2020 CRF450 and 2020 KXF450 for a photoshoot, and by the end of the day had Cahuilla pretty dialed on the big fo-fiddy.

So that said, I'm even more convinced the 250 two stroke is the ideal MX platform. It all boils down to sluggishness. The 250F's suffer from this less, but man, the 450's are just big boats compared to a nimble, modern, 250 2st. You feel that weight in the air, braking, cutting down for a line, holding on under acceleration, everywhere. It's not just mass, it's the additional rotational weight of the engine, and all those extra moving parts, also.

You go from a 4st to a 2st and the 2st feels like a featherweight fighter. Nimble, agile, easier to move around, and overall doesn't tire me out as quickly.

Power
Powerwise I do notice 250F's to be lacking power on a track like Cahuilla with lots of hills and soft dirt. Riding the 450's the other day I had that moment of 'OMG SO MUCH POWER' but when I sat down and thought about it, I was coming out of the turns, into the huge power robbing hills with big jumps at the end of them, relatively the same on both the 450 and my personal 250 2st. Whereas on a 250F it's a bit more of a struggle.

Numbers: Power to Weight
0.239 hp/lb - 2020 KX450 = 233lbs and 55.8 HP ($9,300)
0.236 hp/lb - 2017 TC250 = 212lbs and 50 HP (47 stock and mine has pipe, silencer, and reeds. Mind you the 2020 TC250 costs $8,400.. so you could buy all those parts easily with the $900 you save over the $9,300 KX)

As such the two bikes are less than 1.27% apart power to weight ratio wise. Your butt dyno isn't going to feel that, but your arms will feel it... hauling a bike around that's 9% heavier (the KX450 4 stroke). The Honda weights 12.26% more (!!), the Yamaha and Suzuki 15.5% 16% more respectively (!!!!!)

Racing:
I *really* dislike the four strokes for racing. I've worked around professional racers, and industry leaders, for over 15 years. They all say the same thing, the four strokes are way more forgiving and easy to ride. Meaning, if you mess up a little bit in a corner, on a SX track (spin the wheel, almost tuck the front, etc) you can literally just turn the throttle on the four stroke and clear the triple. From almost a dead stop, in 2nd gear, a 450 YANKS down low. However on a 250 two stroke, a mistake like that probably means you aren't clearing the next jump, and someone will pass you. Mistakes had racing (not injury) consequences, which in turn led to better racing.

Costs
Four strokes cost more to build, maintain, and race. This comes from the factories and A-level teams racing them. I'm not just making this up. This is what the heads of those organizations say.

Want to build your own. Johnny Joe Vet Racer? FMF's top 4-stroke SX pipe & silencer combo is $874. Good lord help you if you race a dual pipe Honda. That'll be $1400 please. Their top 2-stroke pipe & silencer? $640, a $234 savings, or 27% cheaper.

Go ahead and price out a full 450 factory motor build, compared to a 250 two stroke, then factor in one or two full rebuilds...

In closing
In closing I feel that a lot of folks are still remembering their 2001 RM250 and then comparing it to a modern 2020 450. Try riding a current-gen 250 two stroke. The KTM 250SX and the Husqvarna TC250. They are amazing. The motors are smooth (counter balanced), power is way more linear than the old days (especially in the 'mild' map. Tracts well), and they handle like a lightweight modern chassis should. Hell my wife, a fairly novice dirt rider, took a spin on my TC250 the other day at the Pala Fox Raceway Women's Day and got off it saying "I see why you like this bike so much! It goes anywhere and wasn't as hard hitting (aka scary) as I thought!"

Ultimately buy and ride what you like, as you can see I ride all types of bikes. The above isn't an attack on anyone, just sharing one person's thoughts, and POV.

Cheers.

PS: I'm sitting at a racetrack corner working, so yes bored and have time to type as I watch bikes go 'round and 'round

Alex.434 wrote:

[b]40 years old C (West Coast) to B (East Coast) MX rider. B off-road / enduro racer. Sporadic Moto-journalist and photo shoot talent. Expert level roadracing...

40 years old
C (West Coast) to B (East Coast) MX rider.
B off-road / enduro racer.
Sporadic Moto-journalist and photo shoot talent.
Expert level roadracing and Supermoto racer.
Current MX bike: Husqvarna TC250
Other bikes: KTM 525 EXC, YZ250F Supermoto, RMZ450 Supermoto, Yamaha R1 Superbike, Alta MX, Alta EX

Personally I prefer to ride motocross on 250 2st's over 250F's and 450F's. When it comes to riding 4st's I've spent a lot of time on 250F's, so am damn comfortable on one of those out on the track, and always liked 250F's over 450F's. Though recently (last Thursday) I spent an entire day on a 2020 CRF450 and 2020 KXF450 for a photoshoot, and by the end of the day had Cahuilla pretty dialed on the big fo-fiddy.

So that said, I'm even more convinced the 250 two stroke is the ideal MX platform. It all boils down to sluggishness. The 250F's suffer from this less, but man, the 450's are just big boats compared to a nimble, modern, 250 2st. You feel that weight in the air, braking, cutting down for a line, holding on under acceleration, everywhere. It's not just mass, it's the additional rotational weight of the engine, and all those extra moving parts, also.

You go from a 4st to a 2st and the 2st feels like a featherweight fighter. Nimble, agile, easier to move around, and overall doesn't tire me out as quickly.

Power
Powerwise I do notice 250F's to be lacking power on a track like Cahuilla with lots of hills and soft dirt. Riding the 450's the other day I had that moment of 'OMG SO MUCH POWER' but when I sat down and thought about it, I was coming out of the turns, into the huge power robbing hills with big jumps at the end of them, relatively the same on both the 450 and my personal 250 2st. Whereas on a 250F it's a bit more of a struggle.

Numbers: Power to Weight
0.239 hp/lb - 2020 KX450 = 233lbs and 55.8 HP ($9,300)
0.236 hp/lb - 2017 TC250 = 212lbs and 50 HP (47 stock and mine has pipe, silencer, and reeds. Mind you the 2020 TC250 costs $8,400.. so you could buy all those parts easily with the $900 you save over the $9,300 KX)

As such the two bikes are less than 1.27% apart power to weight ratio wise. Your butt dyno isn't going to feel that, but your arms will feel it... hauling a bike around that's 9% heavier (the KX450 4 stroke). The Honda weights 12.26% more (!!), the Yamaha and Suzuki 15.5% 16% more respectively (!!!!!)

Racing:
I *really* dislike the four strokes for racing. I've worked around professional racers, and industry leaders, for over 15 years. They all say the same thing, the four strokes are way more forgiving and easy to ride. Meaning, if you mess up a little bit in a corner, on a SX track (spin the wheel, almost tuck the front, etc) you can literally just turn the throttle on the four stroke and clear the triple. From almost a dead stop, in 2nd gear, a 450 YANKS down low. However on a 250 two stroke, a mistake like that probably means you aren't clearing the next jump, and someone will pass you. Mistakes had racing (not injury) consequences, which in turn led to better racing.

Costs
Four strokes cost more to build, maintain, and race. This comes from the factories and A-level teams racing them. I'm not just making this up. This is what the heads of those organizations say.

Want to build your own. Johnny Joe Vet Racer? FMF's top 4-stroke SX pipe & silencer combo is $874. Good lord help you if you race a dual pipe Honda. That'll be $1400 please. Their top 2-stroke pipe & silencer? $640, a $234 savings, or 27% cheaper.

Go ahead and price out a full 450 factory motor build, compared to a 250 two stroke, then factor in one or two full rebuilds...

In closing
In closing I feel that a lot of folks are still remembering their 2001 RM250 and then comparing it to a modern 2020 450. Try riding a current-gen 250 two stroke. The KTM 250SX and the Husqvarna TC250. They are amazing. The motors are smooth (counter balanced), power is way more linear than the old days (especially in the 'mild' map. Tracts well), and they handle like a lightweight modern chassis should. Hell my wife, a fairly novice dirt rider, took a spin on my TC250 the other day at the Pala Fox Raceway Women's Day and got off it saying "I see why you like this bike so much! It goes anywhere and wasn't as hard hitting (aka scary) as I thought!"

Ultimately buy and ride what you like, as you can see I ride all types of bikes. The above isn't an attack on anyone, just sharing one person's thoughts, and POV.

Cheers.

PS: I'm sitting at a racetrack corner working, so yes bored and have time to type as I watch bikes go 'round and 'round

ace402 wrote:

What pipe is on your Husky?

jeffro503 wrote:

That would be a Scalvini , which came off my bike. Black Husky version FMF 2.1 power core silencer as well. Great combo for big outdoor...

That would be a Scalvini , which came off my bike. Black Husky version FMF 2.1 power core silencer as well. Great combo for big outdoor tracks.

Alex.434 wrote:

[b]40 years old C (West Coast) to B (East Coast) MX rider. B off-road / enduro racer. Sporadic Moto-journalist and photo shoot talent. Expert level roadracing...

40 years old
C (West Coast) to B (East Coast) MX rider.
B off-road / enduro racer.
Sporadic Moto-journalist and photo shoot talent.
Expert level roadracing and Supermoto racer.
Current MX bike: Husqvarna TC250
Other bikes: KTM 525 EXC, YZ250F Supermoto, RMZ450 Supermoto, Yamaha R1 Superbike, Alta MX, Alta EX

Personally I prefer to ride motocross on 250 2st's over 250F's and 450F's. When it comes to riding 4st's I've spent a lot of time on 250F's, so am damn comfortable on one of those out on the track, and always liked 250F's over 450F's. Though recently (last Thursday) I spent an entire day on a 2020 CRF450 and 2020 KXF450 for a photoshoot, and by the end of the day had Cahuilla pretty dialed on the big fo-fiddy.

So that said, I'm even more convinced the 250 two stroke is the ideal MX platform. It all boils down to sluggishness. The 250F's suffer from this less, but man, the 450's are just big boats compared to a nimble, modern, 250 2st. You feel that weight in the air, braking, cutting down for a line, holding on under acceleration, everywhere. It's not just mass, it's the additional rotational weight of the engine, and all those extra moving parts, also.

You go from a 4st to a 2st and the 2st feels like a featherweight fighter. Nimble, agile, easier to move around, and overall doesn't tire me out as quickly.

Power
Powerwise I do notice 250F's to be lacking power on a track like Cahuilla with lots of hills and soft dirt. Riding the 450's the other day I had that moment of 'OMG SO MUCH POWER' but when I sat down and thought about it, I was coming out of the turns, into the huge power robbing hills with big jumps at the end of them, relatively the same on both the 450 and my personal 250 2st. Whereas on a 250F it's a bit more of a struggle.

Numbers: Power to Weight
0.239 hp/lb - 2020 KX450 = 233lbs and 55.8 HP ($9,300)
0.236 hp/lb - 2017 TC250 = 212lbs and 50 HP (47 stock and mine has pipe, silencer, and reeds. Mind you the 2020 TC250 costs $8,400.. so you could buy all those parts easily with the $900 you save over the $9,300 KX)

As such the two bikes are less than 1.27% apart power to weight ratio wise. Your butt dyno isn't going to feel that, but your arms will feel it... hauling a bike around that's 9% heavier (the KX450 4 stroke). The Honda weights 12.26% more (!!), the Yamaha and Suzuki 15.5% 16% more respectively (!!!!!)

Racing:
I *really* dislike the four strokes for racing. I've worked around professional racers, and industry leaders, for over 15 years. They all say the same thing, the four strokes are way more forgiving and easy to ride. Meaning, if you mess up a little bit in a corner, on a SX track (spin the wheel, almost tuck the front, etc) you can literally just turn the throttle on the four stroke and clear the triple. From almost a dead stop, in 2nd gear, a 450 YANKS down low. However on a 250 two stroke, a mistake like that probably means you aren't clearing the next jump, and someone will pass you. Mistakes had racing (not injury) consequences, which in turn led to better racing.

Costs
Four strokes cost more to build, maintain, and race. This comes from the factories and A-level teams racing them. I'm not just making this up. This is what the heads of those organizations say.

Want to build your own. Johnny Joe Vet Racer? FMF's top 4-stroke SX pipe & silencer combo is $874. Good lord help you if you race a dual pipe Honda. That'll be $1400 please. Their top 2-stroke pipe & silencer? $640, a $234 savings, or 27% cheaper.

Go ahead and price out a full 450 factory motor build, compared to a 250 two stroke, then factor in one or two full rebuilds...

In closing
In closing I feel that a lot of folks are still remembering their 2001 RM250 and then comparing it to a modern 2020 450. Try riding a current-gen 250 two stroke. The KTM 250SX and the Husqvarna TC250. They are amazing. The motors are smooth (counter balanced), power is way more linear than the old days (especially in the 'mild' map. Tracts well), and they handle like a lightweight modern chassis should. Hell my wife, a fairly novice dirt rider, took a spin on my TC250 the other day at the Pala Fox Raceway Women's Day and got off it saying "I see why you like this bike so much! It goes anywhere and wasn't as hard hitting (aka scary) as I thought!"

Ultimately buy and ride what you like, as you can see I ride all types of bikes. The above isn't an attack on anyone, just sharing one person's thoughts, and POV.

Cheers.

PS: I'm sitting at a racetrack corner working, so yes bored and have time to type as I watch bikes go 'round and 'round

jeffro503 wrote:

Gawd dang Alex.......that is is one of the most in depth , informative posts I think I've ever seen on here. Posting hard facts , and...

Gawd dang Alex.......that is is one of the most in depth , informative posts I think I've ever seen on here. Posting hard facts , and experience......can't get much better than that.

jeffro503 wrote:

Gawd dang Alex.......that is is one of the most in depth , informative posts I think I've ever seen on here. Posting hard facts , and...

Gawd dang Alex.......that is is one of the most in depth , informative posts I think I've ever seen on here. Posting hard facts , and experience......can't get much better than that.

Hoseclamp wrote:

2 strokes are clearly better since the AMA had to give the 4 strokes a displacement advantage.