2012 KTM 450 SX-F- Article from Motocross Action Magazine November 2011

2012 450 SXFQ: First and foremost, is the 2012 KTM 450SX-F full injected?
A: Nope, and unlike the mob majority of a world sold on technology, the MXA wrecking crew is glad .why? History has proven that fuel injection, for all its hype ,does not make an engine better in the first year of its development .think about how awesome the 2008 Honda CRF450 engine was and how one-dimensional the fuel-injected 2009 crf450 was. The same scenario has replayed itself with a host of bikes that go from awesome to mediocre with the advent of EFI. Given our druthers, we’ll keep the big, broad and bold power that a carb produces until all the experimenting is done (on someone else’s dime).

When KTM deems fuel injection necessary, let’s hope they have better luck than majority of their competitors did in year one of EFI. Virtually every previously carbureted bike lost horsepower and went flat on top after switching to fuel injection .each brand save for Kawasaki, struggled  for two or more years before getting back what they lost. We’d prefer not to waste a year or two trying to get back to where the KTM already is.

Q: How does the 2012 KTM 450SX-F engine differ from the 2011 450SX-F ???
A: In one way and one way only. The 2012 KTM 450SX-F engine gets the most creative clutch ever put on a production  bike (we’ll get to it later).

Q: Is the 2012 450SX-F faster than 2011 450SX-F ??
A: No. Why note? Because it is the same engine  in every detail-save for the clutch.

Q: How good is the 2012 KTM 450SX-F’s powerbrand??
This is everyman’s powerband. It has such a broad and useable output that there is something for everyone from rank beginners to ranked AMA pros. It is hard to imagine a powerband that is so easy to use at low RPM (from 5000 RPM to 7000 RPM),but still rips from 7500 all the way to its 11,600 RPM sign-off. It is the breadth, from bottom to top, that makes the 450SX-F so easy to ride. While its peak horsepower is a respectable 53.24 horsepower at 8800 rpm, the KTM 450SX-F is still making 49 horsepower at 11 grand. And even when the rev limiter kicks in at 11,600 rpm, it is pumping out 45 horsepower. That is all useable power-to the very last drop.

The 2012 KTM 450SX-F doesn’t make the most horsepower in the class (the 2012 KX450F peaks out at 55.50 at 8,900 rpm), but it has the broadest, easiest-to-use and most organic power on the track. You just roll it on and it goes. It doesn’t lurch into action at low rpm. It doesn’t go flat on top. It doesn’t hang at peak.  It just keeps going. If you want to go faster, all you have to do is keep the throttle pegged.

Q: What don’t we like about the 2012 KTM 450SX-F powerband ??  
Now that we have told you how much we love the KTM 450SX-F’s powerband, we need to tell you what we don’t like about it. First, the MXA test rider, the more he wanted a harder and more abrupt hit. The vets and novices loved the easy roll-on power, but the pros wanted it to go now , or sooner.

Our solution was to gear the 450SX-F down(from a 52 tooth rear sprocket to a 53).this punched up the low-end and made things happen  quicker-and allowed us to get to third sooner. In the end, the vet and intermediate test riders preferred this gearing also. The gearing could go even lower for a pro if the traded the countershaft and rear sprockets for a 13/50. The stock 14/52 has a 3.714 ratio; our preferred 14/53 generates a 3.786 ratio, and 13/50 yields a 3.846 ratio (the equivalent of a 14/54).

2012 450 SXF

“Shhhh: the 2012 KTM 450SX-F meets both the AMA and FIM sound standards. Most 2012 can’t pass both tests.”

Q: Would the 2012 KTM 450SX-F run better if it were fuel injected??
Maybe, and maybe not.  As a rule , fuel-injected  450s tend to run crisper down low and flatter on top. This is the opposite of the 450SX-F’s personality. On the news front, KTM has a new, fuel-injected, die-cast 450cc engine in its 2012 450EXC enduro bike (and this is the engine that Ryan Dungey will want to use if he moves to KTM ). But it is not currently in motocross tune. As for now, we are glad that KTM has stuck with the trusty 41mm Keihin FCR.

“Personality: There is no other 450cc engine that can be as gentle at low RPM and powerful at high RPM as the KTM 450SX-F. It has an amazing versatile powerband.”

2012 450 SXF

Q: What’s with the weird clutch ??
It’s not weird; it is creative-the most creative clutch ever put in a production bike. How so?

1)    Steel basket. The steel basket is smaller and stronger than the previous unit. Which was a copy of the 2008 CRF450 clutch. It will never wear out or get notches in the tangs.
2)    Primary gear. The primary gear is CNC-machined directly into the clutch basket. This eliminates the need to rivet a separate gear to the back of the basket-in addition to making the clutch pack narrower.
3)    Rubber dampers. KTM has installed rubber dampers inside the inner hub to cushion the shock of the drivetrain.
4)    Belleville washer. Instead of six separate coil springs to provide tension , the 2012 KTM clutch uses one large cupped washer (KTM calls it diaphragm spring )to provide the tension
5)    Spring preload. Unlike coil-spring clutches, the Belleville washer can be preloaded for more or less tension by turning a stepped disc.
6)    Driven plates. The driven plates are steel instead of aluminum, which lessens wear on the plates and reduces oil contamination. Take note that the outermost and innermost steel plates are thinner than the rest of the clutch plates.
7)    Hydraulics. The whole system is hydraulic, which means that it self-adjusts and lasts twice as long as a cable clutch.
8)    Feel. Every MXA test rider felt that the new clutch had a more precise and positive feel than the old coil-spring clutch. We set the adjustable preload on the stiffest setting.

Q: how does the 2012 KTM 450SX-F handle ??

Once you get the fore/aft balance right, this bike handles a dream. The 63.5-degree head angle tracks accurately through corners and goes down straights like its on rails. Is it better than Suzuki, Kawasaki, Honda or Yamaha?
Yes. It is significantly better than the Honda, Yamaha or Kawasaki but only better than the Suzuki in that it’s more versatile; the rm-z450 is tuned to corner like a banshee-and little else.

Q: What did we like ??

The like list:
1)    Rear brake seals. On past Brembo rear brakes the seals inside the rear master cylinder could  get nicked at extremes  of pedal travel. For 2012, Brembo repositioned the brake bleed hole so that it doesn’t touch either seal.
2)    White plastic. The airbox and side number plates are now white instead of black, which means that you don’t need white backgrounds to put numbers on the 350 or 450-although 250 riders will need black backgrounds.
3)    Handling. if we were going to hand out a medal to the best-handling bike, we’d give the award to KTM . it may not turn as sharply as the rm-z , but it doesn’t shake at speed.
4)    Sound. on the fim’s two-meter-max test, the KTM pumped out a legal 115 db, and it also passed the AMA’s current 94 db standard(by the skin of its teeth)
5)    Powerband. No powerband can be perfect for every rider, but the KTM 450SX-F produces the best overall spread of power . it delivers something for everybody-from slow to fast.
6)    Clutch. This is a bulletproof clutch that will last a rider a lifetime. Better yet, clutch abusers will get it to last longer than any other clutch on the market.
7)    Electric start. Once you try it , you will wonder  why every 450 doesn’t have it.
8)    Holeshot device. KTM includes a holeshot device in the crate with every 2012 450SX-F.
9)    Brakes. These brakes are better than anything found on a Japanese 450.

2012 450 SXFQ:what do we really think?
The fact that the KTM 450SX-F is relatively unchanged for 2012 might seem like a deal breaker, But since most of its competitors are changed even less, the big katoom doesn’t suffer by comparison. As the winner of the 2012 and 2011 450 shootouts, the 2012 KTM 450SX-F has a high-class pedigree.

2012 450 SXF- Order Now!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s