cdarb250

Member
Mar 31, 2008
5
0
I have an 88 CR250 I just finished rebuilding. I need some help on getting the jetting set. I need someones expert opinion on what I should set the carb at jets,clip,air screw. Any help greatly appreciated. Thanks Chris


Elevation 800ft
Pwk Air striker carb
Fmf Gnarly pipe
Shorty silencer
Boyeseen rad valve and carbon reeds
1.6mm over
Average humididty 50 percent
40:1 91 octane
Mostly trail and pit riding
 
Last edited:

helio lucas

~SPONSOR~
Jun 20, 2007
1,020
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from fmf website:
main: 185
needle: stock in 3rd position (1st is the top groove in the needle)
air screw: 1.5 turns from full closed
 

cdarb250

Member
Mar 31, 2008
5
0
So you figure that would be a good starting point? I have the jetting instructions FMF sent with the pipe, I just wasn't sure how much the intake and oversize would change those numbers.
Thanks for the reply
 

helio lucas

~SPONSOR~
Jun 20, 2007
1,020
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the bigger carb needs to be compensed with richer jetting, and the over size ask for sligthy leaner jet...
you could start richer than fmf just to be safe and than progressive go leaner...
 

cdarb250

Member
Mar 31, 2008
5
0
Thanks for the info.

The specs for FMF and Boyeseen are alot different. So I decided to call FMF and they said I can go by there specs They don't think I will have to adjust much at all if any. I think there specs are a safe starting point in comparison to Boyeseen. I will start with the 185 62 3rd combo at 32:1 and see what I get. I just bought a bunch of jets. I am going to spend the next few days tweaking here and there see what I come up with. I just want to make sure the mods I have done are going to be worth the money.


Thanks again
 
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