Motor comparison: KTM 400 EX/C vs. SX

[MWEISSEN]

I debated whether to put this here or on the Euro-bike area....

It's well-known the difference between the WR and YZ 4 stroke motors, but is there any difference in the KTM 400 EX/C engine vs. the SX, ie carb, cams, etc? I'd like to get one or the other when I sell my WR400. I don't care about electric start or lights, and the 48mm forks on the SX are attractive, just as long as stiction isn't much higher.

As always, this group's infinite wisdom is held in awe!!

 

[HiG4s]

The SX has a light flywheel and close ratio trans.
The MXC has the heavier flywheel but the SX trans.
The EXC has both the heavier flywheel and wide ratio trans.
I beleive the only significant difference in the close and wide ratios is in low gear and high gear.
I think the suspension is set up different but should still be the same units.
I don't believe there is any difference in the engines.
Also the SX has 19 inch rear tire, the MXC and EXC have 18 inch rear tires.

 

[Strick]

Hagi has ran down a few of the areas, but the suspension is VERY different. On the '02's the SX has 48mm forks vs. the exc 43mm. The spring rate in respective forks are SX-44, exc-42. Shock rear spring is a PDS 7 on the SX, and PDS 6 on the exc. The exhaust performance is night and day. A local race association member used an SX silencer on his MXC for a couple of rides, and would not even bolt the stock exhaust back on because it restricted it so bad. He bought a T-4.

I love the 48mms. I have not heard of a KTM stiction problem. I had this problem once on my 300. A fork oil change cured it.

You don't need an e-button on the 400. It is a one kick bike.

The 2 gallon gas tank on the SX could become an issue, I guess. I am getting around 26-28 mpg in race conditions.

 

[Anssi]

Originally posted by Strick

I love the 48mms. I have not heard of a KTM stiction problem. I had this problem once on my 300. A fork oil change cured it.

They don't stick, since the 48s are sloppy as heck(like any works fork I guess) :) My dad's -02 380 got a seal leak after maybe 5 hours.

 

[Strick]

Answer: Fork Booties

Anssi:

I have run neoprene (sp?) fork booties on all my bikes for the last two years --> no leaks. I do agree that the 48mm's are not real tight. I seldom get any air out of them when I bleed them (after every ride). And you are right - definitely NO stiction