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EBR Performance - Jetting Specs

Jetting is one of the most important elements of a racing engine.  Optimum performance can only be achieved with accurate jetting regardless of the extent of modification.  We have put together this jetting database from what works best with our bikes with VP C12 race fuel (mixed 32:1 for two strokes) at sea level and 80 degrees.  We have listed these specs to assist riders and mechanics with initial reference.  Engines will run slightly different with special fuels, weather conditions or modifications so these starting points may not be the best final selection for your engine.  Incorrect jetting can typically be characterized with as a bog, miss, sputter, pop or cut-out.


Jetting refers to the fuel metering adjustments in the carburetor.  The adjustable circuits on most two strokes include an air screw, pilot jet, needle, needle position and main jet.  The adjustable four stroke carb circuits refer to the fuel screw, pilot jet, air jet, accelerator pump, needle, needle position and main jet.


*NOTE- Be aware that lean jetting can cause damage to expensive parts of an engine.  Carburetor tuning should be done by a professional that can diagnose a rich or lean condition.

BIKE MAIN JET NEEDLE CLIP PILOT

AIR/FUEL SCREW

 GEARING PLUG

NOTES
2001 CR 80 120-122 2-3 52 1.5 BR10EG
2001 CR125 360-370 2 50 1.8 52 BR9EG
2001 CR250 400 2 30 2 50 BR8EG
2001 CR500 172 2 55 1.5 BR8EG
2001 KDX200 155 3 45 1.5 BR8EG Run richer jetting with air box lid removed
2001 KX125 350 3 42 1.5 BR9EG
2001 KX250 158 2 52 1.5 BR8EG
2001 RM 80 190-195 3 27.5 1.5 48 BR10EG  
2001 RM125 450 2 27.5 1.5
2001 RM250 158 2 48 1.5
2001 YZ 80 290 2 35 1.5 48 BR9EG
2001 YZ125 450 2 27.5 1 49 BR9EG
2001 YZ250 175 2 50 1.5 51 BR8EG
2001 YZ250F 175 5 48 2.75 50-51
2001 YZ426 178-180 4 45 2.75 51 CR8E 48P W/ EXH
2002 CR 80 120-122 2 52 1.5 BR10EG
2002 CR125 390 3 32.5 1.5
2002 CR250 CUT SLIDE 1MM
2002 KTM 65 200 32
2002 KTM125 190 2 48 1.5
2002 KX 60 190 3 35
2002 KX 65 200 3 27.5 1.5
2002 KX 85 138 3 48 1.5
2002 KX125
2002 KX250
2002 KX500 168 3 52 1.5
2002 RM 85 120-122 2 48-50 1.5 48 BR10EG
2002 RM125 430 2 30 1.5
2002 YZ 85 138-140 2 1.5 48 BR9EG
2002 YZ125
2002 YZ250 175 2 50 1.3 50-51 BR8EG
2002 YZ250F 175-178 48 2.25
2003 CR 85 120-122 2 52 1.5 BR10EG
2003 CR125 430 35 BR9EG
2003 CR250 400 GBHY38-70 1 40 1.5 49 BR8EG
2003 KTM 65 200-210 2 32 1.5
2003 KTM125 190
2003 KX 65 190 3 48 1.5
2003 KX 85 138 NAPE 3 48 1.5
2003 KX125 400-410 2 37.5 1.5 BR9EG
2003 RM 85 120-122 2 48-50 1.8 48 BR10EG
2003 RM250 165 2 45 1.5 50 BR8EG
2003 YZ 85 138-140 2 48 BR9EG
2003 YZ125 49-50 BR9EG
2003 YZ250 175 2 50 1.2 50-51 BR8EG
2003 YZ250F 180 4 42 1.75 CR9E
2003 YZ450   CR8E
2004 CR 85 122   2 55 1.75      
2004 CR125 420 LEAN OPT. 2 37.5     BR9EG  
2004 CR250F 158 42 2  
2004 CR250 380  OPTION 3       BR8EG  
2004 KX125 410 2-3 37.5 1.75 13/51 BR9EG
2004 KX250F 172 4 42 2 CR8EB  
2004 KX500 170 2 55 2 14/47
2004 RM 85 122 2 45 2 48
2004 RM125 390 6CHY16-63 2 37.5 1.75 50
2004 RMZ250 172 4 42 2 CR8EB  
2004 RM250 168 2 45 1.5 BR9EG
2004 YZ 85 138   2 48        
2004 YZ125 410   49 BR9EG Richer for Ultimate2
2004 YZ250F 178 4 45 1.75

2004 YZ250 175 2 50 1.3

2004 YZ450F 178     45

2005 CR85   2   1.75

2005 CRF250 162 3 42 2

#55 leak jet
2005 CRF450 170   4          
2005 KX 85 138 NAPE 3 48 1.5
2005 KX125 410 2-3 37.5 1.75 13/51 BR9EG
2005 KX250F 172 4 42 2 CR8EB  
2005 KX250                
2005 RM 85 122 2 45 2 48
2005 RM125 390 6CHY16-63 2 37.5 1.75 50
2005 RMZ250 172 4 42 2 CR8EB  
2005 RM250 168 2 45 1.5 BR8EG
2005 RMZ450 170   45 1.75  
2005 YZ 85 138-140   2          
2005 YZ125 410 LEAN OPT. 3 37.5 1.75 49 BR9EG Richer for Ultimate2
2005 YZ250F 178   4 45 2      
2005 YZ250 175   2 50 1.3   BR8EG  
2005 YZ450F                
2006 CRF250 165 3 42 2

45 Leak jet
2006 KX250F 172   3 42 2   CR8EB 45 Leak jet
2006 KX450F               55 Leak jet
2006 YZ 85                
2006 YZ125 410   3 37.5 1.75   BR8EIX  
2006 YZ250 175   2 50 1.3   BR8EG  
2006 YZ250F 175   Std 42 2.75 47MX/49SX   55 Leak jet
2006 YZ450F 168   5 45 2.25      
2007 CR85 142 2 52 2  

 
2007 CRF150     42 2

45 Leak jet
2007 CRF250 165 3 42 2

 
2007 CRF450       2

 
2007 KX65             BR9EG  
2007 KX85 138       2   BR9EG  
2007 KX250F 172   3 42 2   CR8EB 45 Leak jet
2007 KX450F       45 2     45 Leak jet
2007 RM85 122 2 45 1.75 BR9EG  
2007 RM125 172 4 42 2 BR9EG  
2007 RMZ250 172          
2007 RMZ450            
2007 YZ85 138   2   2      
2007 YZ125                
2007 YZ250F 175   Std 42 2.75 47MX/49SX   55 Leak jet
2007 YZ250 175   Std 50 1.75      
2007 YZ450F       45 2.5     55 Leak jet
2008 CR85 142 2 52 2  

 
2008 CRF150     42 2

45 Leak jet - Wire pump
2008 CRF250 182 3 42 2

60 Leak - Turn AP 3.5 in 

2008 CRF450       2

 
2008 KX65             BR9EG  
2008 KX85 138       2   BR9EG  
2008 KX250F 172   3 42 2   CR8EB 45 Leak jet - Wire pump
2008 KX450F       45 2     45 Leak jet
2008 RM85 122 2 45 1.75 BR9EG  
2008 RM125 172 4 42 2 BR9EG  
2008 RMZ250 172          
2008 RMZ450            
2008 YZ85 138   2   2      
2008 YZ125                
2008 YZ250F 175   Std 42 2.75 47MX/49SX   55 Leak jet
2008 YZ250 175   Std 50 1.75      
2008 YZ450F       45 2.5     55 Leak jet