400ex question

[250xjohn]

Hi, i just changed my 400ex oil. it had 10w-30 but i used 10w 40. it still runs hot especially in this weather. I could not get a hold of 20w-50 today, which would reduce the heat, as i read in another thread. I have an extra oil cooler but the side cases still feel extremely hot even after a fairly short ride. Could the wrong jetting have anything to do with it?

Thanks

[JOHNDOE83]

Yeah jetting has alot to do with heat, what kind of mods does your 400ex have?

[2003TrX400eX]

all hondas run hot lol. but jetting could be wrong or just need to be tweaked.

[250xjohn]

thanks for the reply. I bought it and it had an HMF slip on pipe. I think it is the stock header, but judging by how the carburetor was reassembled after it was cleaned I don't think the owner changed the jet. Otherwise stock motor.

[CJM]

They are too lean from the factory.

Try a 152 or 155 and a 42 pilot jet and turn the fuel/air screw in all the way then out 2.5 turns

[250xjohn]

which screw is the air/fuel screw?

[250xjohn]

And the stock jetting is 148 and 38 or something like that? is it necessary to change the pilot jet? It does not have trouble starting, but i guess ill bump up to a 40 anyway. And thanks for the information

[CJM]

Its the little screw located next to the idle screw/bracket on the bottom of the carb.

Pilot jets too lean as is the main. Ever notice its a pain to start the EX when its cold outside? Its not getting enough fuel. A 42 pilot gives it enough, will turn right over first time you hit the button.

Im not sure why honda jetted it that way, guess it worked for them wherever they tested it out.

[250xjohn]

Ok thanks a lot. And a 155 main should work fine? or higher?