So when is the YZ350F/FX going to appear ?

[grayracer513]

Well, you have two groups of people; one who wishes their 250F had more grunt, and one who wish their 450 was as nimble as their 250F.  What they want, then, is a bike as light and agile as the 250F, but with power like a 450, and unfortunately, nothing like that exists, nor, frankly, is it likely to.

 

I rode a KTM 350 a while ago, wasn't impressed, really.  I think the suspension kept me from enjoying the ride as much as I should have, but it was neither as nimble as a 250F, nor did it have power like a 450.  It was definitely fast, but lacked the low end torque a 450 has.

[cowboyona426]

I rode a KTM 350 a while ago, wasn't impressed, really.  I think the suspension kept me from enjoying the ride as much as I should have, but it was neither as nimble as a 250F, nor did it have power like a 450.  It was definitely fast, but lacked the low end torque a 450 has.

 

That pretty much sums up how I felt after spending a few minutes on one myself.

[GHILL28]

An '04 YZ250F with a 310cc stroker kit was one of the most fun bikes I've ever ridden.  That came closer to bridging the gap between the two than the KTM 350cc did for me honestly.

[JonL515]

If Yamaha wants market share and relevance off road, these products would give them that.  A fuel injected, electric start 300 2 stroke ?  With Yamaha reliability and suspension ?   Are you kidding me ? 

 

I'm a 4 stroke guy, but I'd run out and buy one.  There are many, many orange bike riders who would kill for SSS forks on a competitive 300 2 stroke.

That is what they need to do, but I am sure there are some people there who don't get the offroad market or are just satisfied with the money they make from what they have right now.  They put very little into the 250x.  What they need is someone to bring a vision of the future of the market and develop a true offroad line of bikes.  They did very well with the 4 stroke versions, but that is because those engines and chassis are already received tons of R&D money.  If they really want to compete with the Euros, they need to update their two stroke line up. 

[grayracer513]

An '04 YZ250F with a 310cc stroker kit was one of the most fun bikes I've ever ridden.

I believe it.  I recall an internal staff survey that Dirt Bike did, asking their writers which 5 bikes they thought were the most fun of everything they'd ridden.  Four of the seven put the YZ250F at the top of the list, and only one didn't include it at all.

 

After I spent a day on my son's up at Lark Canyon, I have to agree they're more fun than stealing watermelons at midnight.

[Not sponsored]

I for one would buy a 350 if they made one, turning the throttle less on your 450 if you don't want that power is fine but the extra rotating mass really makes a 450 feel much heavier, especially whipping it through the trees. Even if a 350 and 450 weighed the same the 350 feels much lighter, plus who really needs 60hp in the woods. The problem with the Ktm imo is it makes all its power up to where most of us don't go, I had a 2012 350sxf with a 365 kit and it was better down low but not enough for me as I like to lug in a higher gear these days. Who knows? Didn't Yamaha make IT's, XT's, and TT's in every displacement imaginable at one time?

[motocrotts]

I just sold my 350 Husky for the 450 Yamaha.  I like the strong bottom a 450 produces VS a 350.  I rev the 250X but I like the stump pulling tonque a 450 produces.

[cubera]

It's not all that expensive to convert the 250X into a 300 or even 340. So it's already being done. I've thought about it but I bought the 250X not for power but for a fun ride that makes enough power but remains uber reliable fro daily thrashings. It's like a treadmill with tires. Don't get me wrong; the 250X is no slow poke.

 

The 250FX is easy enough to put a big bore kit on as well. I have no idea of how well it performs, how reliability is affected, or how much it costs. Easy enough to find out for those with an interest.

 

The 450FX feels like a brute compared to the 250FX. I tried to swap the dialed in re-sprung and re-valved suspension off the 250FX onto the 450FX and it didn't work as well as I thought it would (still better then OEM but not that much). I had to send it off again for 450FX specific springs and valving changes. These changes are needed for the 450FX for reasons beyond it being heavier. It is really apples to oranges.

 

The 450FX makes tons of power everywhere so I'm ultra satisfied with the engine. Where I had to flog the 250FX to maintain momentum I can sit on my fat ass and twist the throttle on the 450 and not really even worry what gear it's in. On the other hand, when there is a technical steep ugly thight switchback I miss the 250FX because of its agility and ability to make the right kind of power in those situations. I don't see where the 350 fits in the scheme. YMMV

[Summit]

If they produce a 350 then you guys would want a 400.

[FORMA MOTO]

If they produce a 350 then you guys would want a 400.

 

I want a 415, when is that coming?

[grayracer513]

...the extra rotating mass really makes a 450 feel much heavier, especially whipping it through the trees.

 

It's not the rotating mass, it's just the mass.  The engine itself weighs 75 pounds, and it's 2 feet off the ground.  If the gyro effect had anything to do with it, you should be able to run the RPM up to about 5000 and put your feet on the pegs at a standstill.  But you can't.

 

Didn't Yamaha make IT's, XT's, and TT's in every displacement imaginable at one time?

Yes they did.  They sold 20 or 30 of them, too.

[weantright]

An '04 YZ250F with a 310cc stroker kit was one of the most fun bikes I've ever ridden.  That came closer to bridging the gap between the two than the KTM 350cc did for me honestly.

I love the 300cc 4t bikes. There are brands out there that make these type of bikes today. If you bleed Yamaha then you will have to wait otherwise switch brands.

 

 

It's not the rotating mass, it's just the mass.  The engine itself weighs 75 pounds, and it's 2 feet off the ground.  If the gyro effect had anything to do with it, you should be able to run the RPM up to about 5000 and put your feet on the pegs at a standstill.  But you can't.

 

Yes they did.  They sold 20 or 30 of them, too.

 

It is the rotating mass, as the rpm increase the mass keeps the bike upright giving the feel of less agile and heavy.

[grayracer513]

It is the rotating mass, as the rpm increase the mass keeps the bike upright giving the feel of less agile and heavy.

 

Funny, why doesn't mine do that?

[weantright]

Yours is magical and defies logic.

[grayracer513]

Yours is magical and defies logic.

 

What defies logic is that you believe the angular momentum of the crank can make the bike hard to lean when it isn't strong enough to keep it upright.

[Bass Mechanic]

If I am not mistaken the crank and the clutch rotate in opposite directions, so if there were any gyroscopic forces at play they would counteract each other. in the air however the wheels provide a much larger effect on gyroscopic forces which is why racers can lay the bike sideways in the air.

[grayracer513]

If I am not mistaken the crank and the clutch rotate in opposite directions, so if there were any gyroscopic forces at play they would counteract each other.

You're right about them counter rotating, but the two shafts are parallel with each other, and angular momentum acts to prevent the shaft axis from tilting in any direction.  The fact that both masses are not rotating the same way is immaterial and has no effect on the resulting forces. 

 

The clutch, however, is vastly lighter, smaller in diameter, and turns at 1/3 the speed of the crank, so it offers very little inertia by comparison.

 

The wheels, as you point out, owing to their much larger diameter, have quite a bit of AM, and are much more effective against chassis roll on the X axis than any other component on board.

[Agazza]

This thread cracks Me up

How about a 600cc, two stroke (or five stroke), twin, with Oil in the swingarm and fuel in the frame like the buells, with a husky composit back end like the 701, and the fuel injection and air filter where the tank should be, so it's still compact, lightweighty and a low vibration bike.

Get cracking Yamaha.

[Zbackcountry]

A 350 four stroke now in the same realm as a 600 cc 5 stroke twin...

Edited May 4, 2016 by Zbackcountry

[motocrotts]

Well, you have two groups of people; one who wishes their 250F had more grunt, and one who wish their 450 was as nimble as their 250F.  What they want, then, is a bike as light and agile as the 250F, but with power like a 450, and unfortunately, nothing like that exists, nor, frankly, is it likely to.

 

I rode a KTM 350 a while ago, wasn't impressed, really.  I think the suspension kept me from enjoying the ride as much as I should have, but it was neither as nimble as a 250F, nor did it have power like a 450.  It was definitely fast, but lacked the low end torque a 450 has.

 

That pretty much goes with any KTM.  Lots of motor with sub-par suspension, alway has and probably always will be.  As long as WP is in the picture.