KTM 350SX-F - a new concept
By TMX Archives on 3rd Jun 10
IT'S not often that a manufacturer comes up with a genuine, all-new model. KTM have not only done just that, they have come-up with a whole new concept - a 350cc four-stroke designed to compete with, and beat, the mighty 450Fs.
The go-ahead Austrian giant has followed its instincts and come up with the 350 SX-F which has been developed using all the firm's resources and personnel including the incomparable Stefan Everts. Toni Cairoli has been winning GPs on his factory 350 but how will the revolutionary 350 SX-F work as a production model. KTM recently launched its latest baby at an exclusive test in Spain, along with its enormous range of two-stroke and four-stroke motocross and enduro weapons.
If there's one thing KTM's never been afraid of, it's producing 'odd' sized motorcycles. Be it their 150cc two-stroke motocross bike or the 200cc enduro bike, the Austrian company has never shied away from producing machines that are a little different to those offered by their competitors.
For 2011 KTM is at it again, this time producing their most radically new 'outsized' bike - the 350 SX-F. Believing 100 per cent that in the case of open class motocross machines less certainly can be more, KTM's R&D team have come up with a 100 per cent new bike with a new DOHC engine, a new chassis, and new bodywork. KTM themselves claim that they've reached a new milestone in motorcycle development with the 350 SX-F and having done what all Japanese manufacturers have (apparently) decided against - develop a new 350cc engine - KTM has gone out on a limb to produce a bike that combines high performance and 'playful' handling.
If there's one thing KTM's never been afraid of, it's producing 'odd' sized motorcycles. Be it their 150cc two-stroke motocross bike or the 200cc enduro bike, the Austrian company has never shied away from producing machines that are a little different to those offered by their competitors.
For 2011 KTM is at it again, this time producing their most radically new 'outsized' bike - the 350 SX-F. Believing 100 per cent that in the case of open class motocross machines less certainly can be more, KTM's R&D team have come up with a 100 per cent new bike with a new DOHC engine, a new chassis, and new bodywork. KTM themselves claim that they've reached a new milestone in motorcycle development with the 350 SX-F and having done what all Japanese manufacturers have (apparently) decided against - develop a new 350cc engine - KTM has gone out on a limb to produce a bike that combines high performance and 'playful' handling.
Truth of the matter is that KTM have gone out on a limb in introducing what sounds like a somewhat crazy concept - that of a smaller capacity bike designed to compete against 450cc machines. Despite the fact that the bike has proved itself as a race winner at the highest level in the hands of Antonio Cairoli and Mike Alessi, as a standard package the big question is can the bike really be competitive against 450cc bikes?
Of course that depends very much on the individual riding the bike, but one thing most who rode the 350 SX-F at the recent official media launch in Spain agreed on was that the bike is certainly competitive. While it's not as powerful as a 450 the new 350 SXF is seriously fast and has more than enough power for all but a handful of riders in any country. It's a seriously competitive all round package that's incredibly easy to ride.
In wanting to produce a bike that has performance close to that of a 450, but with handling more akin to a 250F bike, KTM has squarely hit the nail on the head.
I'll hold my hand up and say that I'm not much of a fan of modern day 450cc motocross bikes. Each year as they get faster and feature more instant power deliveries I like them less and less. What many top-level riders are able to do on 450cc bikes is extremely impressive. All I ever find myself doing is trying to pull big gears in order to dull the power. Oh, and scaring myself after about four or five laps.
250cc four strokes have long been my preferred motocross bike of choice as they're relatively easy to ride, easy to handle, and generally great fun. I ride a 250F because I enjoy riding them as much as I dislike riding 450s!
The 350 genuinely does combine some of the best elements of both 250F and 450F machines, namely handling and useable but not too strong power. Curious to find out if the 'odd' sized displacement meant a slightly odd riding experience, it didn't take too long to realise that it didn't. The 350F is, in my opinion, the real deal. Exactly the kind of motocross bike I, and I'd say quite a few riders, have long wanted but has never been available.
As most people know by now the 350 is a 100 per cent new bike. It's much more than just a new engine in their existing chassis. The 350 DOHC motor is extremely compact, features a layout that's close to the 250F, features electronic fuel injection, weighs 27.4kg, has electric start - although a kick-start kit is available to save additional weight - and revs to 13,000rpm.
Sticking with a chrome-moly steel frame and not opting for an aluminium chassis like many of their competitors, and continuing to use a cast swing arm, the big news as far as the chassis of the new 350F is concerned is the fact that the bike now has a rear suspension linkage system.
Having for so many years opted not to follow trend, KTM suggests that Supercross is the reason behind introducing the linkage. With KTM clearly hoping for success in the US market, where a linkage system is an absolute must because it's what the Japanese 'Big Four' have, KTM claim to have tried no fewer than 24 different chassis configurations before deciding on the geometry used on the production 350F.
The biggest single difference between the '11 chassis and an '10 frame, aside from the brackets used to hold the linkage, is the fact that the top shock mount has been isolated away from the main frame. Done so to allow more flex, much of the testing of the new frame centred around finding a compromise between stiffness and flex.
Interestingly, while the bike has a new chassis, when sitting on it the 350F feels no different to last year's 250F with the positioning of the bars and footpegs seemingly unchanged. The bike is certainly slim, and the ergonomics allow easy movement on the bike.
The styling of the new bike is much different to previous KTM models, and also quite different to what all other manufacturers are currently offering. Gone are the angular plastic panels, replaced with curvier, more flowing, lines. Mixing orange with black and white panels the 350, like all of the '11 motocross range from KTM, has a very distinctive new look.
So what's it like to ride? In a word - awesome. But that wasn't my initial impression.
First time out on the bike not knowing if would be best to rev it hard like a 250F or use the strength of the motor more like a 450F, I found I wasn't able to gel with the bike quite as I hoped. Whenever I was in a low gear or a high gear it seemed to be the wrong gear. Initially I preferred the 250F.
What I realised second time out on the bike is that it needs to be ridden relatively, but not overly, hard. It needs to be ridden as a 350 but much more like a 250F than a 450. Producing its maximum power between 9,000 and 12,000 rpm, when the bike is kept within its sweet spot it's an absolute joy to ride.
To keep the bike singing along it does have to be ridden relatively hard, but it's easier to keep the bike between the desired revs than on a 250F due to the motor having stronger power. With no need to use the clutch to get the bike revving out of corners, unless you let revs drop too low, the fact that you can roll-on and roll-off the power easily makes it feel more like a 450.
But the big difference is the fact that there's no hit to the power, and certainly no top-end scariness. The strength of the power is impressive, notably stronger than a 250F, but retaining the character of a 250cc motor. It can be revved almost as hard as you like, but because the power is stronger than a 250F you can, providing you're in the sweet spot, keep shifting up the gears.
What is instantly noticeable when on track is that the bike isn't a big 250 or a lesser powerful 450 - it's a 350, and as such it has it's own character. And as such it has to be ridden as a 350. Albeit that is more like a 250F than 450, but the bike does feel like a new machine, not one that has been derived from something else.
There were a few areas on the track where the bike excelled. Coming into pretty much any corner the bike could be made to take a tight inside line. Be it a faster turn or a 180-degree corner the bike not once wanted to take a wider line. The bike's ability to hold an inside line, and the ease with which it could be made to stop, change direction, and turn was very much like a 250F. The strength of the power when coming out of the corner though is when it reverted back to being a 350.
Only once did I really notice that the bike was fuel injected. On one flat, slippery corner no matter how gently the power was rolled on the front end would want to push away ever so slightly due to the initial surge of the injection system. Everywhere else on the track the bike injected faultlessly, with clean, crisp power whenever needed.
When discussing the bike's handling the obvious question is what's the linkage like, and is it better than the PDS system? That's the $64,000 questions when it comes to not only the new 350 SX-F but all of KTM's four-stroke motocross range.
Knowing that KTM wouldn't have gone to the trouble, and expense, of developing and putting into production a linkage system if they, and their test riders, didn't think it was better than a non-linkage system, it makes it hard to step onto the bike thinking anything other than 'it must be better'. And as there's never been a 350 SX-F without a linkage there's nothing to compare it to either.
Suspension is a hugely subjective area of bike set-up and performance and for every rider you speak to that says linkage is better there'll be a rider that's perfectly happy with his PDS system.
The new 350 certainly handled impeccably during the launch, but it has to be said the track wasn't over rough. With braking and acceleration bumps few and far between it wasn't really possible to get a feel for how the bike performed in the very area where the linkage is supposed to be better over the PDS.
While serious braking and acceleration bumps were few and far between it was hard to fault the bike anywhere around the track. The settings of the forks seemed a little on the softer side at times, but the balance of the bike was again hard to fault.
What KTM have created is a hugely versatile bike. In the hands of a serious racer it will be competitive against 450s, certainly during longer motos as the bike can be ridden harder for longer. But the 350F is a package that can be enjoyed by club racers equally as much. Doing the seemingly impossible in coming up with a bike that will have real all-round appeal, the ease with which the bike can be ridden, and the fact that it's certainly 'not too much' like a 450 can be, makes it great fun to ride.
While it will likely appeal more to 250F riders looking to step-up onto a bigger bike than 450F riders looking to downsize, the bike will likely draw riders from both directions. The fact that KTM has fitted a linkage will undoubtedly attract some new customers to the brand, while the fact that the bike is proving itself competitive at the highest level in both Europe and the States says much about its 450 beating qualities.
Going against the grain and producing a 350cc bike has been a bold move on KTM's behalf. But by having the balls to do what others haven't, they've come up with a hugely appealing product. One that's as competitive as it is easy and enjoyable to ride.
What of the rest of the SX range?
It's not just the 350 SX-F that's new when it comes to KTM's '11 motocross range. The Austrian company has seriously re-vamped their SX models with the 250F getting fuel injection like the 350 with both the 250F and 450 getting the new linkage chassis and new styling.
The biggest change for the 250F motor is the fact that it is now fuel injected. A kick-start motor as standard, the 2011 engine allows quick and easy fitment of an electric starter. It features a new camshaft with new valve timing and improved gas flow to give more torque.
A new exhaust design, which features a refined header pipe and a silencer with a bigger opening, offers more power, while the new 42mm Keihin engine management system gives 'spontaneous and powerful throttle response'. The 'user setting tool', which is available as a Power Part, allows data logging, for those that want to get all Moto GP with their bike set-up!
The 450 is essentially the same engine and carburettor set-up as in '10, just fitted into the new linkage chassis. The clutch gets refined for '11while like the 250F the bike gets a new silencer.
The three bike two-stroke SX range all feature the new chassis and linkage combination giving them a fresh new look. With the engines of the 125cc and 150cc bikes remaining largely unchanged both feature new silencers and air box designs.
Changes to the 250cc two-stoke run a little deeper. As well as the new chassis the bike also features a new exhaust and a new cylinder, designed to offer higher torque and make the bike easier to ride.
All 2011 SX models feature the latest 'made in Austria' WP suspension.
The KTM 2011 Enduro range
2011 is all about KTM's motocross range with the new 350 leading the way, which is one reason why the enduro models haven't received too many changes. The other being that there's not much that needs fixing as far as their eight-bike range is concerned.
The popular 250F only receives a few changes the most notable of which being the fitting of a transparent fuel tank. Previously only available on the Six Days models for '11 all EXC bikes come with the practical clear tanks. With new graphics and hand guards fitted as standard the versatile little bike will unquestionably remain hugely popular.
The 400 EXC comes in for a few more changes. As well as the clear tank, hand guards, and new decals, it gets a few internal engine mods such as a new material for the valve spring retainers and new timing for the automatic decompressor for improved starting.
The 450 receives the exact same changes as the 400. The most popular bike in its class, like with all models KTM have opted not to try and fix problems that don't exist and instead have simply freshened-up the look of the bike. The clear tank and white rear mudguard certainly lighten up the look of the bike. The 530 receives the exact same changes as the 450.
The two-stroke EXC range also remains largely unchanged. Fitted with new silencers the 200 gets a 'new character' thanks to a new exhaust system and new carb' settings.
The big news as far as the 250 is concerned is the fitting, as standard, of an electric starter. With the electric starter proving popular on the 300 KTM have put in onto the 250, where it will undoubtedly prove equally as popular. The 250 also gets a new cylinder, like the motocross bike, and a new piston, a new exhaust and a new six-speed gearbox.
Completing the EXC two-stroke range the 300 also gets the new cylinder and piston as well as the new exhaust and carb' settings. While the changes to some of the 2011 models are minimal for 2012 it's likely that the new chassis will be carried over to the enduro range - but without the linkage system. The smart money is also on KTM fitting the 350 will lights..!
SPECIFICATIONS
2011 model KTM 350SX-F
ENGINE
Engine type: Liquid cooled, single cylinder, 4- stroke, with 4-valve DOHC with
finger followers
Displacement: 349.7 cc
Bore x stroke: 88 x 57.5 mm
Compression ratio: 13.5 : 1
Starter: Electric starter 12V 3 Ah
Transmission: 5 gears
Carburettor: Keihin EFI, 42 mm throttle body
Lubrication: Pressure lubrication with 2 oil pumps
Engine lubrication: SAE 10W50
Final drive: 5/8 x 1/4" Chain (14 : 50 gearing)
Clutch: Wet multi-disc clutch, operated
hydraulically
Ignition: Keihin EMS
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal, aluminium 28/22 mm
diameter
Suspension
Front: 48 mm WP USD
Travel: 300 mm
Rear: WP-Monoshock with linkage
Travel: 330 mm
ANCILLARIES
Brakes: Disc brakes 260 mm (front)/ 220 mm (rear)
Rims: 1.60 x 21" (front); 2.15 x 19" Excel (rear)
Tyres: 80/100-21" (front); 110/90-19" (rear)
Main silencer: Aluminium
DIMENSIONS
Wheel base: 1495 ± 10 mm
Ground clearance
(unloaded): 375 mm
Seat height: 992 mm
Tank capacity: approx. 7.5 litres
Weight (no fuel): approx. 103.9 kg
SPECIFICATIONS
2011 model KTM 125/ 200/ 250/ 300EXC
ENGINE
Type: Liquid-cooled, single cylinder, 2-stroke with exhaust control (125, 200 & 250)/ with TVC power-valve (300)
Displacement: 124.8 cc/ 193 cc/ 249 cc/ 293.2 cc
Bore x stroke: 54 x 54.5 mm/ 64 x 60 mm/ 66.4 x 72 mm/ 72 x 72 mm
Starter: Kickstarter (125, 200 & 250)/ Kick- and electric starter (300)
Transmission: 6 gears (125 &200)/ 5 gears (250 & 300)
Carburetor: Keihin PWK 36 S AG
Lubrication: Pre-mix oil lubrication (1 : 60)
Final drive: X-ring chain 5/8 x 1/4"
Clutch: Hydraulic wet multi-disc clutch
Ignition: Kokusan
CHASSIS
Frame: Central double-cradle-type 25CrMo4 steel
Subframe: Aluminium
Handlebar: Neken aluminium 28/22 mm
SUSPENSION
Front: 48 mm WP USD with 300 mm travel
Rear: WP PDS shock absorber with 335 mm travel
Brakes: Disc brakes 260 mm (front)/ 220 mm (rear)
Rims: 1.60 x 21" (front); 2.15 x 18" Excel (rear)
Tyres: 90/90-21" (front); 120/90-18" (125 &200)/ 140/80-18" (250 & 300)
Main silencer: Aluminium
DIMENSIONS
Wheelbase: 1471 ± 10 mm (125 &200)/ 1475 ± 10 mm (250 & 300)
Ground clearance: 390 mm (125 &200)/ 385 mm (250 & 300) (unloaded)
Seat height: 985 mm
Tank capacity: approx. 9.5 litres
Weight (dry): approx. 97 kg (125 &200)/ 100.8 kg/ 103.1 kg
SPECIFICATIONS
2011 model KTM 125SX/ 150SX/ 250SX
Engine
Type: Liquid-cooled, single cylinder, 2-stroke with exhaust control (125 & 150)/ with TVC power-valve (250)
Displacement: 124.8 cc/ 143.6 cc/ 249 cc
Bore x stroke: 54 x 54.5 mm/ 56 x 58.4 mm/ 66.4 x 72 mm
Starter: Kickstarter
Transmission: 6 gears (125 & 150)/ 5 gears (250)
Carburetor: Keihin PWK 38S AG (125 & 150)/ Keihin PWK 36S AG (250)
Lubrication: Mixture oil lubrication 1:40 (125 & 150)/ 1:60 (250)
Final drive: Chain 5/8 x 1/4"
Clutch: Hydraulic wet multi-disc clutch
Ignition: Kokusan
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal aluminium 28/22 mm
suspension
Front: 48 mm WP USD with 300 mm travel
Rear: WP PDS shock absorber with 336 mm travel
Brakes: Disc brakes 260 mm (front)/ 220 mm (rear)
Rims: 1.60 x 21" (front); 2.15 x 19" Excel (rear)
Tyres: 80/100-21" (front); 100/90-19" (rear) (125 & 150)/ 110/90-19" (250)
Main silencer: Aluminium
DIMENSIONS
Wheelbase: 1480±10 mm (125 & 150)/ 1495±10 mm
Ground clearance: 385 mm (unloaded)
Seat height: 992 mm
Tank capacity: approx. 7.5 litres
Weight (dry): approx. 88.8 kg (125 & 150)/ approx. 93.8 kg (250)
SPECIFICATIONS
2011 model KTM 250/ 400/ 450/ 530EXC-F
ENGINE
Engine type: Liquid cooled, single cylinder, 4-stroke with 4-valve DOHC
Displacement: 248.6cc/ 393.4cc/ 449.3cc/ 510.4cc
Bore x stroke: 76 x 54.8 mm/ 95 x 55.5 mm/ 95 x 63.4 mm/ 95 x 72 mm
Compression ratio: 12.8 : 1/ 11.1 : 1/ 11.9 : 1/ 11.9 : 1
Starter: Kick and Electric start 12V 4Ah
Transmission: 6 gears
Carburettor: Keihin FCR MX 39
Lubrication: Pressure lubrication with 2 (250)/ 3 oil pumps (others)
Final drive: X-ring chain 5/8 x 1/4"
Clutch: Hydraulical wet multi-disc clutch
Ignition: Kokusan (250, 400 & 450)/ Kokusan digital (530)
CHASSIS
Frame: Central double-cradle-type 25CrMo4 steel
Subframe: Aluminium
Handlebar: Neken aluminium 28/22 mm
SUSPENSION
Front: 48 mm WP USD with 300 mm travel
Rear: WP PDS shock with 335 mm travel
ANCILLARIES
Brakes: Disc brakes 260mm (front)/ 220mm (rear)
Rims: 1.60 x 21" (front); 2.15 x 18" Excel (rear)
Tyres: 90/90-21" (front); 120/90-18" (250)/ 140/80-18" (others) (rear)
Main silencer: Aluminium
DIMENSIONS
Wheelbase: 1475 ± 10 mm
Ground clearance: 380 mm/ 381 mm/ 382 mm/ 383 mm
Seat height: 985 mm/ 986 mm/ 987 mm/ 988 mm
Tank capacity: approx. 9.2 litres
Weight (dry): approx. 105.7 kg/ 113.9 kg/ 113.9 kg/ 113.9 kg
SPECIFICATIONS
2011 model KTM 250SX-F/ 450SX-F
ENGINE
Engine type: Liquid cooled, single cylinder, 4-stroke, with 4-valve DOHC & finger followers
Displacement: 248.6 cc/ 449.3 cc
Bore x stroke: 76 x 54.8 mm/ 97 x 60.8 mm
Compression ratio: 13.2 : 1/ 12.5 : 1
Starter: Kick-start (250)/ Electric start (450)
Transmission: 6 gears/ 5 gears
Carburetor: Keihin EFI, throttle body 42 mm (250)/ Keihin FCR MX 41(450)
Lubrication: Pressure lubrication with 2 oil pumps (250)/ 3 oil pumps (450)
Final drive: Chain 5/8 x 1/4"
Clutch: Hydraulical wet multi-disc clutch
Ignition: Keihin EMS (250)/ Kokusan (450)
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal 28/22 mm aluminium
SUSPENSION
Front: 48 mm WP USD
Travel: 300 mm
Rear: WP-Monoshock with linkage (250)/ WP PDS shock absorber (450)
Travel: 330 mm
ANCILLARIES
Brakes: Disc brakes 260 mm (front)/ 220 mm (rear)
Rims: 1.60 x 21" (front); 2.15 x 19" Excel (rear)
Tires: 80/100-21" (front); 100/90-19" (250)/ 110/90-19" (450) (rear)
DIMENSIONS
Ground clearance: 375 mm/ 371 mm (unloaded)
Seat height: 992 mm
Tank capacity: approx. 7.5 litres
Weight (dry): approx. 99.9 kg/ 106.9 kg
FOR FULL TEST SEE T+MX NEWS, FRIDAY, JUNE 4, 2010
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