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Workshop => Carburetor, Intake, and Exhaust => Topic started by: mgleason05 on September 04, 2014, 10:13:28 PM

Title: 38 A/S jetting help...
Post by: mgleason05 on September 04, 2014, 10:13:28 PM

Got a  38 A/S the other day, but have no idea on where to start with jetting. I have a stock cylinder that I believe has been bored once. FMF pipe and exhaust. Any ideas on what to start with? No porting has been done.

Title: 38 A/S jetting help...
Post by: rk88r on September 05, 2014, 06:52:32 PM

Assuming you're not running an airbox lid. Summer temps (central MN) I would try 48pj, dej 3rd groove, and 165 mj. A little cooler weather 4rth groove, and a 170 mj. Probably rich Idk listen to your motor.

Title: 38 A/S jetting help...
Post by: The Phantom on September 06, 2014, 10:03:07 AM

I think my 38 A/S with a ported stock cylinder with fmf exhaust had a 170 main and a 50 pilot, needle in the 3rd groove open lid airbox.

Title: 38 A/S jetting help...
Post by: jcs003 on September 06, 2014, 10:39:05 AM

http://trx250r.org/threads/78-Jetting-data-base

john