Why am I losing??

[Dizing400ex]

Hey guys

My buddy and I have 400s. His an 05 and mine an 06.

His mods are sparks timing advance, removed arrestor, WB Rev Box. He DID NOT rejet

My mods are in my sig. Basically the same mods but i have dynojet kit, KN filter w outerwear.

He has about 300 miles on the quad, and mine maybe has 100...

I am jetted at the middle(3rd) groove on the needle and a 155 main and his quad will pull about 2 lengths in 3rd and then we stay even all the way out... WHY???? He weighs about 35 lbs more then me and hes got less stuff done?

The only thing i can think of is that my jetting is off???

Ive changed from the 165 main to 160 to 155 and everytime i go leaner the race gets closer.

Should i start messing with the needle or what??

Is his just more broken in than mine or what?? Help!!

thanks
Dustin

[B-rad D]

do u have a Rev Box

[underpowered]

dont take this the wrong way, but he may just be a better rider than you. you may have also jetted a little rich, causing less power on the top end, while he is running lean since he did not rejet giving him more power. also, Why are you running a 7 series plug? stock is an 8, suggest high performance is a dpr9z

[dirteater74]

Maybe he slipped in a smaller C/S on his bike when you were'nt looking. Are you sure you guys are geared the same and have the same size tires?

[knelson]

Is his yellow?


J/K :D stock and stock my buds 400 was faster than mine, we would switch and his still was faster? if its slightly faster It could be as simple as he has more air in his tires!! Or It could have been the break in procedure he used and it seated the rings better. just put a 14 tooth sproket on the front and be done.

[underpowered]

Originally posted by knelson
Is his yellow?


J/K :D stock and stock my buds 400 was faster than mine, we would switch and his still was faster? if its slightly faster It could be as simple as he has more air in his tires!! Or It could have been the break in procedure he used and it seated the rings better. just put a 14 tooth sproket on the front and be done.

05 and 06's already have a 14 on the front, if he is gonna drop he has to go to a 13

[knelson]

oh I see I knew the gearing was different but I thought it was transmission ratio's, I know my 450r has a 13 tooth up front.
are the new ones supposed to be faster or something? You can tell I haven't kept up w/ the 400:confused:

[400exrider707]

Jetting is definitely too rich on the main. Dyno-jet jets are even bigger than that of the same size keihen. here:

hole-----Kehein #--- DynoJet #---Mikuni #
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


So look what a 155 dyno would be, its like a 172ish kehein. You need to go way leaner. I only ran a 150-152 with just a filter on mine.

[underpowered]

yes, try going leaner on the main. I am running a 178 kehein main on my 400 with race fuel. try like a155 kehein, a 140-142 dynojet

[bwamos]

Originally posted by 400exrider707
Jetting is definitely too rich on the main. Dyno-jet jets are even bigger than that of the same size keihen. here:

hole-----Kehein #--- DynoJet #---Mikuni #
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


So look what a 155 dyno would be, its like a 172ish kehein. You need to go way leaner. I only ran a 150-152 with just a filter on mine.

Nice chart. :)

[400exc]

its the same hee, i have a 02 and my friend has a 03 and mine beats his cause im better at shifting, and ridin than him. I also wiegh alot less than him! lol but yea i have my arrestor off in the winter, and i dont rejet, and i can still beat him

[MXRACER86]

Don't forget you have skidplates on yours which adds more wieght!

[400exrider707]

Originally posted by underpowered
yes, try going leaner on the main. I am running a 178 kehein main on my 400 with race fuel. try like a155 kehein, a 140-142 dynojet

I ran a 155 main on mine with 11:1 piston, stage 1 cam, slip-on and uni w/o the lid, and it was still a tad rich.

[Dizing400ex]

WOW I didnt realize im running that rich.... thanks so much guys!!!

Weve both been riding since we were about 5 years old. I would definitely consider myself an expert RIDER... not mechanic ..hahaha.. No he doesnt shift or ride better than I do because I dont lose to him in the shifts, its while were in the middle of 3rd gear... he instantly pulls 2 quads and stays there.. I dont gain and neither does he.

Ill definitely go back to about 145 and see what happens... I know stock is a 148...

I had no Idea dynojets are that much off!!! thanks so much!

BTW - he has heavier skids than i do, plus hes got A arm skids and I dont!!!

Same gearing, Same tires, everything except what i listed..

The heat range 7 plug is the DPR9Z .. Its what i have in the quad....

thanks alot for the replies!! Boy will he have a surprise next time!!

Dustin:devil:

[400exrider707]

stock is a 148 kehein, try a 140 dyno-jet. That should be more than enough, and should still be good for the cold air.