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Carb jetting for a 98 RMX 250.?

Need advice on jetting my Suzuki 98 RMX 250. I have a Boyesen rad valve, and fmf performance pipe with spark arrester. Everything else is stock. I've been running 40:1 mix, with the aircleaner cover removed to get it running smooth. Right now I've got a 170 main, 60 slow, stock needle, 3rd clip, and 1 1/2 turns on the air screw. Boyesen says go with a 162, but my dealer can't find one. It's running rich, and will foul every once and a while. I have a BR9EIX plug in now, and it does pretty good with that. Does any one know where I might find a 162 main jet, or the specs on the hole size so I can ream out my 155 jet (which does not run well when installed). Also, I just went through the entire carb, and cleaned out thoroughly, all passages are clean, and it's a stock carb, a Klein.

Public Comments

1. Most any motorcycle dealer or parts store Should have jets for that carb. Stock Jet is a 165. ............................ Jet Drilling is a Crap Shoot,,pure trial and error. Keihin Jet #'s are a NOMIMAL size,,,,just a "name",,,not an actual dimension.. They're Numbered about 2% to 5% LARGER than actual size in mm. Example,,,a #160 may be 1.55mm actual size. I'm sorry,,wish I had a chart to give you some precise numbers,,,no such thing exists to my knowledge. Anyway,,,Try the other Local Dealers---you'll Probly Find the right jets you need. If You want to Drill them... A)A Drill bit makes a Slightly Larger Hole than it's marked size---usually B) Keihin Jets are Smaller than their Marked Size,by a small amount A 160 Jet will be Smaller than 1.60 mm So,A 1.60mm Drill would make LARGER than #160 Jet. On 2 counts,,,Overdrill of the bit,,and the Calibration system. A 1.60mm Drill would probly produce APPROXa #165Jet #54 Bit = 0.0550 " approx equiv to 1.40mm =0.0551" #53= 0.0595 ............................. 1.50mm= 0.0591 #52= 0.0635 ............................. 1.60mm= 0.0630 #51 =0.0670............................. 1.70mm= 0.0669 Looks like a #53 would be the one to try 1st Keep in mind,,A #160 JET is smaller than 1.6mm hole Then try the #52 next for a 1.6mm Hole. That should be equiv of a 162 or 165 Jet,,,HOPEFULLY ................... Here's a mail order source. $3 each Jets ,,$7 Shipping flat rate http://www.jetsrus.com/main_page.htm Good Luck