Jetting for 3000-5000 Elevation


10 replies to this topic
  • JokerWR

Posted February 08, 2014 - 12:04 PM

#1

I have read through a few of the threads regarding this but am still unsure of what exactly to buy ... 

I have an 08 wr450 that is still in stock form.

I have purchased the GYTR replacement tip that is larger than uncorking the first plug from the exhaust.

I want to remove the airbox snorkel, pull the grey wire, install the yz throttle stop screw, install an adjustable fuel screw, replace the stock muffler tip with the larger gytr one, and rejet the carb with genuine kehnin parts for 3000-5000 ft elevation ...

from this site .... http://www.jetsrus.c...F_2003-2009.htm

 

My question is which jets, needles, or any other part from that site do you think i should get?



  • RockerYZWR

Posted February 08, 2014 - 01:00 PM

#2

There's a really good jetting database in the stickies - read through and find someone at a similar elevation.
I'm at 4300 ft and currently run a 170 main (while it's cold out), 48 pilot, 45 leak jet, GYTR needle at third clip from the top, stock start and primary air jets, and I used a tach to tune the fuel screw but I think it's about 1.75 turns out. I am very happy with my set up.

  • Krannie McKranface

Posted February 08, 2014 - 01:00 PM

#3

BILLIONS and BILLIONS of posts on this

 

165

45 pilot

ncvs or yamaha gytr yz needle 3rd clip

50 leak jet

Tokyo Mods apump linkage spring upgrade

R&D remote fuel screw



  • JokerWR

Posted February 08, 2014 - 05:38 PM

#4

There are billions of posts and all of them are conflicting.

in fact both of your replys list different sizes lol

Screw it ... i'm gonna pull the carb off and give it to zipty racing they are only 30 min from me. they made my 06 yz450f go from a 5 or 6 kick sluggish lean popping pyle to running like it had efi for $125 4 or 5 years ago. and that included a fuel screw and magnetic float bowl drain plug.

 

Thanks anyways guys!


Edited by JokerWR, February 08, 2014 - 05:41 PM.


  • Krannie McKranface

Posted February 08, 2014 - 06:48 PM

#5

I am giving you ball park jetting information.

The condition of your carb, fuel, air filter type, exhaust type and condition, etc, all play a part in exactly what jetting numbers to choose.

 

This is a FREE forum giving you FREE advice. You should be reasonably grateful, at least.

 

If you don't want the advice, don't take it. But don't complain about it!

 

If you would like an exact jetting specification, take it to a dyno A/F tuner, for about $550.00



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  • JokerWR

Posted February 08, 2014 - 06:56 PM

#6

I am giving you ball park jetting information.

The condition of your carb, fuel, air filter type, exhaust type and condition, etc, all play a part in exactly what jetting numbers to choose.

 

This is a FREE forum giving you FREE advice. You should be reasonably grateful, at least.

 

If you don't want the advice, don't take it. But don't complain about it!

 

If you would like an exact jetting specification, take it to a dyno A/F tuner, for about $550.00

 

You must have taken my comment wrong ... I apologize and assure you that I appreciate the help! 

I was basically just saying rather than buy a bunch of jets, hunting down a bunch of parts from various websites and pulling the carb on and off a few times to get it right I decided to throw in the towel and take it to zipty as they did much more for my last carb than just putting a couple jets in it, it was spot on, and it wasn't an arm and a leg.



  • RockerYZWR

Posted February 08, 2014 - 09:13 PM

#7

Unless you really don't mind dropping the money, you can probably get a solution at least 95% of what Zipty is going to come up with for about $75 less including the fuel screw. It's really not all that mystical. If you start with the numbers I used (maybe go 168 on the main with your stock pipe for the winter), mod your accelerator pump linkage, and tune your fuel screw accurately, you will have a bike that starts easily cold or hot, revs instantly off idle, and does not have a flat spot anywhere in the powerband. Assuming of course that everything else with the bike is squared away. You have to take the carb off anyway, might as well give it a shot. And keep in mind you can switch out pilot, main, and starter jets in about 20 minutes without having to pull the carb.
Anyway, just my thoughts.

  • Krannie McKranface

Posted February 08, 2014 - 09:49 PM

#8

Zipty is going to give you the same treatment you can buy, for about $30 in parts

I understand the lure of quick and easy jetting, no matter what the cost.

That is what I do with my suspension and motor work now days: I just don't want to do that stuff anymore.

 

If you motor is bone stock inside, an acceptable level of jetting will not be critical or difficult to achieve.

Of the jetting I listed, the pilot, needle, and fuel screw are the most important part of the puzzle.

The feel of the motor is in the apump system.

 

 

But the apump portion is technically not jetting, and is not addressed by Zipty specifically.

That is why the apump spring upgrade and leak jet are recommended....but if it doesn't squirt right...

It defines the throttle response of the motor, and requires visual confirmation of the squirt event, for duration and timing....often there are corrosion issues.



  • JokerWR

Posted February 09, 2014 - 10:38 AM

#9

They CLAIM to do work to the float bowl area and emulsion tube as well as ultrasonically clean the carb.

 

http://www.ziptyraci...carburator-mod/

 

i was just looking at it like this ...

 

fuel screw $15

Magnetic drain plug $20

Jet kit $40

 

Paying them $50 to ultrasonic clean the carb and work their magic on it seems like a deal to me.



  • RMK800

Posted February 09, 2014 - 04:49 PM

#10

Carburetor Settings. 8/2/2013
45 pilot
50 leak jet
162 main jet
NCVS - 3rd Clip
2 turns fuel screw
Marge spring

I ride between 4500 to 9000.

Awsome! Airbox mode and lexx pipe.

Put a 165 In it. Use the other settings.

  • funt

Posted February 09, 2014 - 04:56 PM

#11

Harbor freight has a cheap ultrasonic cleaner.  I'm not sure if it's big enough to do a carb.






 
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