owenlo

Member
Oct 28, 2001
214
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Anyone figured out how to do the BK Mod on the 2003 YZ250F? It looks to me that they have changed the carb design and I can't see how it is possible. If anyone has done it could you post some pics? Thanks in advance!

Obie#723
 

BSWIFT

Sponsoring Member
N. Texas SP
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Nov 25, 1999
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Try this link, here.  Then check out the tech articles.
 

owenlo

Member
Oct 28, 2001
214
0
Very aware of that procedure. The 2003 carb is a different design than the 02 and 01's. All articles I have read apply to the 01's and 02's. Have yet to see how it is done on an 03. The 03 carb does not have the same lip to drill through and install the screw through. Instead of the rubber boot covering the side as the 02 and 01's, the 03's have a metal cover that screws on and takes up the space where the screw was supposed to go.

Obie#723
 

BSWIFT

Sponsoring Member
N. Texas SP
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I was unaware of the differences.
 

owenlo

Member
Oct 28, 2001
214
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Yeah, I think there are alot of people that are unaware. I was unaware also, until I tried it and saw there was no room for the screw. Thanks for trying.

Obie#723 ;)
 

Smit-Dog

Mi. Trail Riders
LIFETIME SPONSOR
Oct 28, 2001
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Obie -

How are you liking that 03' 250F compared to the KDX? What type of terrain do you ride? Post a ride and comparision report, likes/dislikes, etc. if you get a chance.

Have you experienced the ignition miss others have reported?

Thanks...
 

whyz

~SPONSOR~
Nov 18, 2001
478
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Originally posted by owenlo
No, Haven't tried that but I guess it won't hurt to try. I'll let you know how it works. ;)

Obie#723
I haven't had the time to adjust mine,by the time I get home,it's been dark
this past week. (It should work though).. I'll definately take off early tomorrow to try it and get our bikes ready for Sat. at Woodland.
(Practice all day from 8am till 5 or 6pm) :cool:
I'm picking up my P-BombSX header tomorrow too :confused:
Can't wait to mate it with my FMF-Q for around my house. :laugh:
I'll be checking that out on Sunday.
See Ya..
 

whyz

~SPONSOR~
Nov 18, 2001
478
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AP screw didn't work. Oh Well, try and try again.
Leak jets hasn't come in yet,darn it.
Maybe the Air Jet?
I wonder what the Starter jet does? :think:

Help? :whiner:
It says in the manual to use a MJ with a lower #.and raise the clip
or vice a versa when you have poor response when throttle is opened quickly.
I thought that had nothing to do with off idle response?
Not sure now. I'm lost. But not giving up just yet.
Got the Q series on though, and the SX P-Bomb header,
Quiet for the neighbors and still has the power that I need,But will get another MX silencer soon but dont know what to get. Still searching. :laugh:
 

whyz

~SPONSOR~
Nov 18, 2001
478
0
Originally posted by whyz
AP screw didn't work. Oh Well, try and try again.

I need a .49 " rod of some sort to adjust the AP screw,to put under the slide (so the manual says) :think:
I readjusted it today and got better off idle response but not with a load.
Still clueless. Oh well,I'l just give her gas for now.
Originally posted by whyz

But will get another MX silencer soon but dont know what to get. Still searching. :laugh:
I made up my mind---> DR.D is being ordered :laugh:
Right now with the Q on I can seat jump a 30' dble 10' away from the face at a dead stop. So the bikes fine with me.
Can't wait for the new system.
 

Barbarian

Member
Nov 22, 2001
302
0
I haven't seen the 03 carb, but why not just glue some washers or something in there to keep the linkage from moving too far. Something along these lines should work ok.
 

endosports

Member
Jan 10, 2002
494
0
Originally posted by Barbarian
I haven't seen the 03 carb, but why not just glue some washers or something in there to keep the linkage from moving too far. Something along these lines should work ok.
Now we all know where you got your name from. :uh:
 

Barbarian

Member
Nov 22, 2001
302
0
Might be crude but it would work. You just need to find an adhesive that would make it reliable. I don't really know anything about welding but you might could braze something in their.

Then again, you could just live with the bog!
 

tmoney

~SPONSOR~
Jan 16, 2002
140
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owenlo,

I had the same problem and could not make the BK mod work for the 03. I checked the timing with a flashlight and as far as I could tell it was definately squirting gas for less than a second and it seemed to be the right timing. Two comments;
1) I wonder if the 01/02 FCR cover plate would fit on the 03? This would provide the space needed to tap...
2) I don't know if simply changing the leak jet to a larger size would have the same net effect? That seems easiest to try first.
3) I know what the manual says about the AP timing setup, but I was wondering if the best way would be to adjust the fuel timing so it hits the slide (5/ of 10 times) and then back down from there so it just clears the slide.

Just ideas...
 

whyz

~SPONSOR~
Nov 18, 2001
478
0
Originally posted by tmoney

Just ideas...

Those ideas are great ones.
Today I'll try the 90 >richer then the leaner 110.
I'll also try diff clip settings as well and a different needle.

It's gonna be a long day :confused:

I think at first when I started to jet this bike, everything was not quite broken in and or seated or whatever and that would make me chase things that aren't there. Well now it should be the time to do it all again :laugh:

I just saw these plugs with 2 gounding straps that a part guy tried to sell me.
What's it for? It's like 7 bucks-> Geeeesh. :think:
 

whyz

~SPONSOR~
Nov 18, 2001
478
0
I've been working long hours so with the Leak Jets,
I just need more time. (So many little baby parts) :silly:
But for now,
I'm going to send my bike to the dealer to see if he can cure it.

He said he'll do it for free. (We'll see) :think:
He'll have my bike for the rest of the week :|
Good time for it>> It suppose to storm.
 
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