Jetting Info 07 450r

[yamahardr15]

I was wondering if anyone new what size jet and how I should tune my carb after adding a full system bill balance exhaust and K&N airfilter. Does anyone have any jetting recomendations?

[d3ktrix]

We can't tell you exactly what will be perfect for your bike. Though can give you a universal starting point for an 07 with a pipe and no air box lid.
You'll have to tune from there by the results. If your at a high elevation you'll have to jet slightly leaner also.

Using keihin sized jets...

165 Mainjet
45 Pilot
HRC Needle Middle clip
55 Leak jet


And don't just do the main jet and skip on the rest like most people do, it will bog when u snap the throttle and pop on decel.

[chevys&honda$]

now im really lost

leak jet?

first time i have heard of that I NEED HELP TO

same question except i have stock header and i want to run with my lid on

[d3ktrix]

Originally posted by chevys&honda$
now im really lost

leak jet?

first time i have heard of that I NEED HELP TO

same question except i have stock header and i want to run with my lid on

The leak jet controls how much accelerator pump squirt goes into the carb, or back into the float bowel.
The stock leakjet is a 70, lets a lot of fuel "leak" out of the AP and back into the float.
Once you add an exhaust and take off the air box lid, you need a stronger AP squirt or else you will get a lean bog when you snap the throttle open.
A #55 leak jet is popular for this setup.

I'm not sure what jets you would run with the air box lid on, I've never jetted a bike for that. I'm sure if you do a search you could find someone who as done it.

[chevys&honda$]

well, i went by the dyno jet instructions to a T, and a few people got me convinced that dynojet is the worst and i think i need to start all over.

right now i have

main-140

pilot- stock

a/f mix 2.5 out

needle- middle clip

lid-on with k&n

lexx mxe slip-on

[d3ktrix]

What does it run like?

BTW a 140DJ is equal to a 152 Keihin MJ

Heres a conversion chart



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

[chevys&honda$]

starts hard and takes long time to warm up, after warm runs good , but pops on decel...

my main mite be a 138 its been a couple of months since i did the jeting, pilot is stock

[d3ktrix]

Originally posted by chevys&honda$
starts hard and takes long time to warm up, after warm runs good , but pops on decel...

my main mite be a 138 its been a couple of months since i did the jeting, pilot is stock

I forgot to ask what year your bike is.

Putting in a larger pilot or turning the Air/Fuel screw out will help will help the cold starting and stop the popping on decel.

If adjusting the A/F screw out doesn't help pump up the pilot 1 size. (Don't go more then 3 turns out on the A/F screw)

If its an 06-07, the stock pilot is a 42, so try a 45.
If its an 04-05, the stock pilot is a 48, so try a 50.
This is with Keihin jets, I don't know how the sizing for dynojet pilots works.

[chevys&honda$]

its an 07,

I think im gone take the carb off this weekend and re-jet im proply gona run with the lid off.

so, i'll try to start with 165 main 45 pilot

[d3ktrix]

Originally posted by chevys&honda$
its an 07,

I think im gone take the carb off this weekend and re-jet im proply gona run with the lid off.

so, i'll try to start with 165 main 45 pilot

Don't forget the leakjet, You'll have a nasty bog off idle if you don't and you'll have to take the carb off all over again.
And your mid range will be lean with the stock needle.

When you increase air flow by adding an exhaust/removing air box you need to richen all of the carb circuits.

[chevys&honda$]

I allready have the dyno needle installed... I think 3rd spot from top or middle...

where do i get leak jets?? what size do i start with?

[d3ktrix]

Can get leakjets anywhere you can get OEM honda parts. Like motosports/bikebandit/servicehonda.
Local power sport shops and dealers should carry them or order them for you.

Part # for the 55 leak is 99108-MEB-0550

[chevys&honda$]

ok, thanks!!


do you work for kbmotorsports??

[d3ktrix]

Originally posted by chevys&honda$
ok, thanks!!


do you work for kbmotorsports??

Nah I'm friends with the owner and he hooks me up on parts.

[dave4881]

Originally posted by d3ktrix
Part # for the 55 leak is 99108-MEB-0550

Is that a Honda part number or Keihin?

Thanks!

[d3ktrix]

Originally posted by dave4881
Is that a Honda part number or Keihin?

Thanks!

Honda
It's the stock leakjet for an 07 CRF450R dirtbike.

[dave4881]

Originally posted by d3ktrix
Honda
It's the stock leakjet for an 07 CRF450R dirtbike.

A couple of questions:

Are the carbs on the 06 & 07 the same?

What is the stock mainjet on an 06?

[Rancher2005]

even though your carb is off I would only make one change at a time so you can see how it affected the entire throttle range. Hope this helps as I've change different jets controlling different things and had to go back to square one

[chevys&honda$]

I just finished re-jetted about an hour ago here it what i ended up with.

lid-off
main 165
pilot 45
a/f mix screw out 2 turns
stock leak jet

tried a 55 leak just didnt seem right

[d3ktrix]

Originally posted by dave4881
A couple of questions:

Are the carbs on the 06 & 07 the same?

What is the stock mainjet on an 06?

On the CRFs?
I think the 07 is different, larger bore and updated AP and other stuff I'm sure.

Stock MJ in an 06 CRF450R is a 168.
178 for an 07.

[yamahardr15]

So heres my final set up: Full HMF Bill Balance Exhaust and a K&N air filter with filter lid on it still. So anyone know what jets or does anyone have any references I should go off of.
Thanks