400ex exhaust upgrade?

[Grimzella]

hello,
I am mostly in the 300ex forums, but my friend had recently got a 2005 400ex. He bought a HMF full exhaust. My question is this.. when i asked about jetting my 300ex .. the great members here told me what to do.. and it worked out perfectly. So i wanted to try it again.. only with the 400ex forum. I live in South Western PA 15301. Elevation is 1,156 FT . when i changed out my main jet from a Keihin 122 (stock) to a 128 (as mentioned in 300ex forum) it was a perfect match worked out nice for my 300ex. My question with the 400ex is.. at my elevation.. what size main jet Keihin should i start out with? can and should i adjust the needle or shim it? does the pilot need changed out? should i open the airbox? any other advise or suggestions would greatly help.
2005 400ex
full exhaust headers with HMF slip on

ps.. did the exhaust headers ever change over the years?
thanks,
Dave

[ginobili07]

I have an 02 with a HMF slip on and i took out the stock jet which was either a 142 or 148 and put in a 150. Didn't need ot take out pilor jet, but i would screw the air/fuel mixture screw in then back it out like 2 turns and play with it from there

[Eviltanker]

I'm in Pa and run a 150/48, bought an adjustable needle and have that on the 3rd clip, screw out 2 1/2 turns.Aftermarket airbox no lid.
hope this helps send you in the right direction.