Skippyams

Member
Jan 24, 2001
8
0
1998 RMX 250 Jetting questions
I have went throuh the top end and replace the RMX head gasket with the 89 RM thinner head gasket to boost the compression up a bit. I have the PC pipe and spark arrester running the 93 octain gas with 50:1 AMSOIL Series 2000 oil. PJ carb 175 main 65 low speet. needle in 3rd position air screw 1 1/4. South East.
When running wide open its seems alittle to crisp I can pull the choke on and it still runs well but when I let off with out the choke being on is seems to want to ping some what but with the choke on it seems to almost cut the motor off.
If any one has any jet settings for a RMX for that year or an RM I would like to know what they are to see if im close.
Thanks for any help.
 

MRRMX

Member
Nov 24, 1999
192
0
That the same jetting in my 93 RMX, I take it your on the oem size needle. I have to run 100 octane gas cut 50/50 with mobile super to stop the death rattle. I had FMF port my jug and cut the head. I am getting around 240psi after 20 minutes of break in. FMF told me years ago to go to a thinner needle to if it was rattleing. I did but it seemed to flat with the thinner one in the carb. I got oil on the rear fender. In the end. It was oem needle and buy 100 octaune gas. Its like 3.29 a gallon. makes for a pain and extra expense, But I never toasted a piston or needed to put a lower end in it.
 
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