crazycarl7

Member
Oct 14, 2007
46
0
I have a 2005 yz250f completely stock. I just bout an aftermarket complete yoshimura exhaust system (header and exhaust). Will the bike need to be jetted and should I get a different air filter? K&N? any suggestions would be helpful
 

BigRedAF

Member
Jan 9, 2005
739
0
Wow, those are high priced kits...

I suppose if you don't have past experience these kits take the guess work out of it, that's worth something.

It looks like they send several jets and a set of instructions for trial and error tuning.
 

BigRedAF

Member
Jan 9, 2005
739
0
http://www.procircuit.com/PCJETTING.htm

This link will take you to Pro Circuit. They have settings for several bikes. On yours they lean the main from a 182 to a 180 and they richen the Pilot from a 42 to a 45, no other changes. These jets will cost about $5.00 each.

This setting is based on sea level to 1500 and 75 degree weather. Your profile is incomplete so this is the best I could do for you.
 

crazycarl7

Member
Oct 14, 2007
46
0
jetting

thats good advice. I am in maryland and normal weather 80 degrees. So these changes would work for a bike with any after market exhaust, not just pro circuit? also were do I buy single jetting needles?
 
Last edited:

BigRedAF

Member
Jan 9, 2005
739
0
The needles are available from your dealer, you will need to order it. However, I don't think you will need to replace your needle, they have 5 clip positions for fine tuning.

The pilot and main jets are usually in stock and easy to replace. Along with those, a simple air/fuel screw depending on 2/4 stroke bike will usually solve your issues.
 
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