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Quick suggestion on main jet
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Posted by: gel1197

I have a 2003 trx 250 ex and it has the following:
-K&N filter, airbox lid still on
-Factory exhaust with an after market endcap. It has a screen for a spark arrester but no baffles.

I live in Central Florida and my son weighs 120 pounds. He rides on trails and woods mostly. Question is what main jet should I run and where should the c-clip be on the needle? Should I mess with the other jets or leave them alone?

I know the answer may be out there but thought I'd ask since the "end cap thing" really wasn't covered in the FAQ section. It's made by Phoenix and it looks and sounds cool. I know I should buy a full exhaust but $$ is tight sometimes.

Posted by: 250excrf250r

quote:
Originally posted by gel1197
I have a 2003 trx 250 ex and it has the following:
-K&N filter, airbox lid still on
-Factory exhaust with an after market endcap. It has a screen for a spark arrester but no baffles.

I live in Central Florida and my son weighs 120 pounds. He rides on trails and woods mostly. Question is what main jet should I run and where should the c-clip be on the needle? Should I mess with the other jets or leave them alone?

I know the answer may be out there but thought I'd ask since the "end cap thing" really wasn't covered in the FAQ section. It's made by Phoenix and it looks and sounds cool. I know I should buy a full exhaust but $$ is tight sometimes.

go up to the dynojet 100 main eclip should be 4th position. the 250ex comes lean from factory so a 100 should be good or a 102 and i would take the lid off and run a 102 but honestly try both

Posted by: ryanh250ex

What brand jets did you plan on using?

To account for Florida heat (supposed to be 85 all week here in Daytona

), try a 102 main if you end up running a K&N/Keihin jet, if dynojet try a 98 or so.

Posted by: gel1197

I have the Keihin jets already. I'll try the 102 this weekend. Should I touch the c-clip or leave it in the factory slot? Should I leave the other factory jets alone? I appreciate the help.

Posted by: ryanh250ex

quote:
Originally posted by gel1197
I have the Keihin jets already. I'll try the 102 this weekend. Should I touch the c-clip or leave it in the factory slot? Should I leave the other factory jets alone? I appreciate the help.

Try it in the 4th slot (one notch below factory setting).