YFZ450 Jetting .

[minerva]

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[minerva]

Hello guys i need some help, i have a 2005 yfz with pro-circuit t4 slip-on, K&N air filter, K&N power lid, quickshot and i also got the tie mod on the carburator. Recently i bought the dynojet kit for my bike and i mount it just like the instructions say: Mainjet 144 needle on groove # 5, dyno pilotjet 48, also 1.5 turn, sea level but the byke fails in midle to high rpm i tried the 160 main and it´s worse and also tried the 150 but it´s the same thing, so i believe that it has too much gas and was wondering if going up a groove on the nidle is the correct thing to do or if i should trie a smaller main jet or even close a bit the gas screw. Thanks

[minerva]

Anybody????

[yfzrider690]

If i were you I would junk that jet kit and go to the dealer and get some keihin jets and the ncvq needle or use the stock needle. With the keihin jets you should be running around a 45 pilot, 165-168 main jet and 3rd or 4th clip down from the top on the needle and 1 1/2 turns on the a/f screw. Jet kits are junk in my opinion, I have only ever bought one and I ended up using nothing out of it.

[minerva]

Originally posted by yfzrider690
If i were you I would junk that jet kit and go to the dealer and get some keihin jets and the ncvq needle or use the stock needle. With the keihin jets you should be running around a 45 pilot, 165-168 main jet and 3rd or 4th clip down from the top on the needle and 1 1/2 turns on the a/f screw. Jet kits are junk in my opinion, I have only ever bought one and I ended up using nothing out of it.

You may be right but since i bought the kit it will have to do. So today i put nidle on the 4th groove and the bike is runing great without the K&N powerlid but when i put the lid on it fails in mid gas, Any ideas? Maybe turn a litle bit the screw?

[99warriorNJ]

Originally posted by minerva
You may be right but since i bought the kit it will have to do. So today i put nidle on the 4th groove and the bike is runing great without the K&N powerlid but when i put the lid on it fails in mid gas, Any ideas? Maybe turn a litle bit the screw?

leave the lid off.. more air more power.. you should ditch the intake setup you have now and get a Fuel Customs Intake. they are pricey but well worth it for the added power they deliver. if you do happen to go that route.. get a 180 keihin main, 45 pilot, 4th clip, 2.5 turns out.

[minerva]

After another try i guive up, i took the bike to a local diller and hoppefully they will make it up...

[ohsobad_chevy]

Originally posted by minerva
After another try i guive up, i took the bike to a local diller and hoppefully they will make it up...

Why did you give up. You won't ever learn by letting someone else do it for you. Jetting is not hard once you learn how to "hear" the motor.

[minerva]

Originally posted by ohsobad_chevy
Why did you give up. You won't ever learn by letting someone else do it for you. Jetting is not hard once you learn how to "hear" the motor.

Yup you are right but i simply lost my pacienc to pull my carb apart, i have changed the main jet 6 times, pull the nidle off 3 times, and open and close the gas screw several times.... Probably my next bike will have electronic injection like all the new ones, so probably (but unfortunatly) i don´t need the knowledge. Anyway i bought the kit for 50$ with postal serviçe from ebay plus +- 70$ for hand laber so i ended up winning, here in Portugal the cheapest you can get the dynojet kit is about 150$. By the way nice forum you guys have. Regards and thanks for the help

[SDRIDER15]

MY GIRLFRIEND HAS A 2006 YFZ450 QUAD. AND IM HAVING PROBLEMS WITH GETTING IT RUNNING RIGHT. IT BACK FIRES A LOT AND WILL DIE OUT WHEN YOU PUNCH THE GAS FROM IDLE. IM GOING TO CHANGE THE JETTING TODAY AND WAS WONDERING IF I COULD GET SOME POINTERS.

*ENGINE IS STOCK
*K&N AIR FILTER WITH AIR BOX LID OFF
*STOCK PIPE WITH SPARK ARRESTER REMOVED.

I WAS GOING TO CHANGE THE JETTING TO 165 or 168 MAIN, 45 PILOT AND THE REST STOCK. WHAT DO YOU THINK THE JETTING SPECS SHOULD BE FOR THIS SET UP?

THANK YOU FOR YOUR HELP.