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View Full Version : 99 400EX first mod


sandtoys0
11-22-2008, 12:40 PM
I want to remove the airbox lid and take out the exhaust baffle and run it that way.
What size jets do I need for those of you running your bike like this?

Thank you,
Rick
motox92
11-22-2008, 02:08 PM
I would just buy an aftermarket exhaust, if you ever wanted to go back to stock you will always have it.
sandtoys0
11-22-2008, 10:12 PM
that wasn't the question--anybody else?
alberto
11-22-2008, 10:22 PM
What type of air filter do you have? I used a K&N, removed the lid and spark arrestor (only on the dunes), and it ran just fine. I didnt change the jets until I upgraded to a full YOSH pipe. I ran that way for almost a year.
sandtoys0
11-22-2008, 10:29 PM
It's stock...When I took the lid off my 450r it wouldn't run at all so I assumed the same would happen with the 400.
alberto
11-22-2008, 10:41 PM
You know now that I think about it. The samething happens when I take the lid off of my 05 450R. It bone stock too. It boggs then it stalls right? Keep in mind I have not removed the spark arrestor so it me be getting to much air and being restricked with the arrestor. Just a thought. I'm interested to see what the resoltion is. GOOD LUCK!!!!!!!!