KTM 520EXCessive power 4U

Joined
May 17, 2000
Messages
137
Likes
0
#1
If any 520 riders can't get enough power. here is your fix :eek: -

Replace the stock OBDTM#2 needle/175 main with an OCEMN#4/168 main.

There will be an instant boost in your power from 1/4 throttle up. More snap at the throttle to loft your from wheel at any time. It works in the 400 also.

----------------------

The needle has more taper which requires a smaller main jet to keep the full throttle jetting unchanged. Leave the pilot (#48) and pilot screw unchanged (about 1-1.25 turns out).

This is a STANDARD TAPER needle for the Keihin FCR carb. It is very close to what the YZ426 and 250F have. The stock needle simply runs extra lean in the midrange. It can be purchased from Sudco at 1-800-998-3529 or Carb Parts Warehouse or your dealer can get it from them.

Have fun and Hang On! ;)

James Dean
 
Joined
Jun 18, 2000
Messages
47
Likes
0
#2
I'll give it a try in my 520sx this weekend. What clip position should I try as a starting point?

I ride at about 3,000 ft.
 
Last edited:
Joined
Oct 21, 2000
Messages
1
Likes
0
#3
James Dean,

Is the needle normally available at a KTM dealer??
Should I run the same jetting at 1000-2000 elevation, 85 - 100 degrees??

Thanks :think
 
Joined
May 17, 2000
Messages
137
Likes
0
#4
That was clip #4 (EMN#4), but if it feels too rich down low switch to #3.

The needle is not a KTM OEM option. It should be.

There has been a great deal of testing and evaluation of jetting with the FCR carb on Yamahas, KTM's, and a few Suzuki's. I've received feedback from riders all over the world. The different combinations of needle diameter, taper, and clip position were all compared. This carb needle is the best all-around choice that I've found. If you're at high altitude EMP is a step leaner, then EMR is another 2 steps leaner after that.

When you get the big jump in power, call up your KTM rep and tell him that James Dean gave you the tip and is willing to do a little new bike testing/consulting on the side. ;)

James Dean
 
Joined
Jun 18, 2000
Messages
47
Likes
0
#5
Thanks James Dean,

Can't wait to give it a try. I neglected to mention I also run a pro circuit silencer. Will this have any effects on your recommendations?
 
Joined
May 17, 2000
Messages
137
Likes
0
#6
JohnnyMac,

With the PC silencer try #4 first and think about clip #5 as a possible option of you have any extra time to test. The more open exhaust may run slightly better with it.

James
 
Joined
Jun 18, 2000
Messages
47
Likes
0
#7
Looks like I'll have to postpone my ride report. "Sudco" and "Carb parts" are both out of stock on the needles.:(
 

Strick

Lifetime Sponsor
Joined
Nov 8, 1999
Messages
1,782
Likes
2
#8
JohnnyMac, the short supply is James Dean's fault. So many riders have taken his sage advice that there is none left:(

Also there is a rumour that James has purchased all the available needles and will the selling them for $25 each, plus shipping:p

Just funnin'

James you are the jettin' MAN!!!:cool:
 
Joined
Feb 25, 2001
Messages
49
Likes
0
#9
Cool! Thanks for the information. As soon as these parts are in stock, I will buy them and put them on.:)
 
Joined
Dec 9, 2000
Messages
129
Likes
0
#10
Servus James,

OCEMN#4/168 main
Do you really mean OCEMN and if yes, where is the difference between OB and OC neddles?

Actually I can't imagine handling more power on my 520, but if it is there ...

Michael
 
Joined
Nov 3, 2000
Messages
11
Likes
0
#11
I am not very carburator savy. Is this something I can do myself with the manual? So I need to pull out the existing needles and replace them with the OCEMN#4/168 main. IS there any other adjusting that will need to be done?
thanks for any info.
 

Shaw520

Damn Yankees
Joined
May 14, 2000
Messages
1,082
Likes
5
#12
Originally posted by drehwurm
Actually I can't imagine handling more power on my 520, but if it is there ...

I HEAR that,.... you can always opt for the optional NHRA braking chute to slow ya down for the corners,..!! :D
However,....if there is a jetting advantage to be had,.... Jimmy D. will find it! :cool:
 
Last edited:
Joined
May 17, 2000
Messages
137
Likes
0
#13
Does Orange Go with Blue?

Drehwurm,

The OC needles are made from brass and the stock OB are an anodized or plated aluminum.

If you REALLY want an OB needle, Yamaha ( :think ) has a part # 5JG-14916-EN which is OBEKN. This is 1 clip richer, so will need a setting of clip #3 rather than #4. Cost is about $15. Wouldn't it just make you sick to use a part from a blue bike? :think

Brettv, If you can get the carb off, you can do it. We left the pilot and pilot screw untouched. (A hard thing for me to accept. :D )

I guess Sudco should stock up on these FCR needles.

James
 
Last edited:
Joined
Dec 9, 2000
Messages
129
Likes
0
#15
Re: Does Orange Go with Blue?

Servus James,

Believe it or not, but my 520 is already BLUE! I even put Yamaha fork guard stickers on it - still miss my WR a little.

If you REALLY want an OB needle, Yamaha ( :think ) has a part # 5JG-14916-EN which is OBEKN.
Honestly, after pondering about this a little I will not start this jetting stuff again - this bike works so fine engine wise, there just is no need to! And I'm busy with the suspension anyway :confused:

We left the pilot and pilot screw untouched. (A hard thing for me to accept.
My dealer put in a 52 pilot right from the start and what should I say - just see above!

Thanks!

Michael