jetting again

[eliasxr400]

2005 trx400ex with following mods-
Engine: 11.1 comp std. weisco, stage 1 hot cam
Exhaust: HMF slip-on, FMF power bomb header-on the way
Intake: K&N with lid off, stock carb

Riding at sea leval between 70-100 degrees

I did a lot of searching with not much help for my mods.

The reason I ask is because I am ordering the header for fathers day. Right now I am right on with my dynojet kit with the biggest jet in the kit. I think it is a 170dj. It is more lean than rich according to the plug. I check the plug when I shut it down at WOT.

How much will a header change my jetting?

Can I use the DJ needle with a keihin jet?

Will I gain much from the Head Pipe with my current mods?

[hornetgod13]

Originally posted by eliasxr400
Can I use the DJ needle with a keihin jet?

I was using a DynoJet needle with keihin jets for nearly 3 months until I finally found out that it was causing a stall/hesitation on quick acceleration from idle. I ended replacing it with a 1999 to 2004 stock adjustable keihin needle and the problem went away. The Dynojet needle is shaped differently and is designed to work with Dynojet adapter and jets.

[CarGuy7a]

you'll gain some power with a header. i just have a cam in mine with the rest of the motor stock and noticed some bottom end when i put my headers on. you may notice a little more than i did seeing that you have higher compression.

as far as jetting i think you would have to go bigger b/c the headers will let the motor breathe better.

[GPracer2500]

170 Dynojet sounds huge. I'd guess your plug reading method is leading you astray.

[eliasxr400]

Originally posted by GPracer2500
170 Dynojet sounds huge. I'd guess your plug reading method is leading you astray.
It may be a 160dj. The one I have in is the biggest on in the kit.

What size keihen should I start at?

[CarGuy7a]

i think the biggest in my DJ kit is like a 170 or 175 i can't remember.

here is a jet conversion chart i picked it up off of here so i'm not saying that it is 100% correct b/c i'm not sure. but it may help a little.

Width------Keihin # -- DynoJets # -- Mikuni #
0.0350---- 92.5--------- 92----------- 86.3
0.0360---- 95----------- 94----------- 88.1
0.0370---- 97.5--------- 96----------- 90.0
0.0380---- 100---------- 98----------- 91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
0.0510---- 132.5------- 124--------- 116.3
0.0520---- 135--------- 126--------- 118.1
0.0530---- 137.5------- 128--------- 120.0
0.0540---- 140--------- 130--------- 121.9
0.0550---- 142.5------- 132--------- 123.8
0.0560---- 145--------- 134--------- 125.6
0.0570---- 147.5------- 136--------- 127.5
0.0580---- 150--------- 138--------- 129.4
0.0590---- 152.5------- 140--------- 131.3
0.0600---- 155--------- 142--------- 133.1
0.0610---- 157.5------- 144--------- 135.0
0.0620---- 160--------- 146--------- 136.9
0.0630---- 162.5------- 148--------- 138.8
0.0640---- 165--------- 150--------- 140.6
0.0650---- 167.5------- 152--------- 142.5
0.0660---- 170--------- 154--------- 144.4
0.0670---- 172.5------- 156--------- 146.3
0.0680---- 175--------- 158--------- 148.1
0.0690---- 177.5------- 160--------- 150.0
0.0700---- 180--------- 162--------- 151.9
0.0710---- 182.5------- 164--------- 153.8
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5

[eliasxr400]

bump

My header will be here in a few days, any idea where to start with the main jets?