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matts06yzf

06 yzf 450 help please

25 posts in this topic

I have a 06 yzf 450 with a whitebrothers mx4 slipon. What are jetting suggestions i get alot of back pressure when i get off the gas and when bike is at idle if i pin throttle bike will flood out or will bog down real bad besides that ir runs great. should i re jet or could it be a plug? please help thanks, Matt, also am i hurting anything if i stays like this for a week or so

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i get alot of back pressure when i get off the gas and when bike is at idle if i pin throttle bike will flood out or will bog down real bad

Back pressure??? The reason a four-stroke dies when you pin the throttle from idle is because the engine isn't creating enough vacuum at those low revs and will bog because of too much air/not enough fuel when the slide opens. If it doesn't bog when you do that while riding, there's no problem. As said above, if it's still jetted as stock and backfires a lot when the throttle is chopped, try a #45 pilot jet.

If you're not sure about what the fuel screw does, read this, it explains other stuff too. http://www.motocrossactionmag.com/me2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=6E5BCFD99FD242B28032722A4D5D52E3

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i get alot of back pressure when i get off the gas
I don't understand this part. What are you saying? It backfires through the pipe? It has engine braking? What?
when bike is at idle if i pin throttle bike will flood out or will bog down real bad
You're a two-stroke guy, aren't you? You can't pin the throttle from idle on any properly jetted four-stroke single. It should respond to sudden opening of the throttle without bogging, but you ain't ever going to get it to respond to a full, instantaneous snap from idle to WOT without completely over compensating the accelerator pump, so get over it.

You need to learn to "roll" the throttle, meaning that you open it slightly and gradually at first, and increasingly faster as the engine responds. It will become second nature after a time, and you'll do it without thinking, and the engine, once jetted right, will sound as if it went from idle to 6000 in an instant.

Having said all that, David's right; the stock pilot is too small for anything below 6000 feet, it seems. Change that to a 45 or 48, and use a main jet in the 165-170 range, and it should run much better.

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Thanks alot guys, i ordered a complete jet kit and I am letting dealer get it right hopefully. I also purchased boysen quick accelerator, is this thing worth the money? any other ideas to help my bike it is new to me. I have been a 2 stroker my whole life love this bike tho, Thanks alot

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Thanks alot guys, i ordered a complete jet kit and I am letting dealer get it right hopefully. I also purchased boysen quick accelerator, is this thing worth the money? any other ideas to help my bike it is new to me. I have been a 2 stroker my whole life love this bike tho, Thanks alot

my advice is get the jetting right before you add the quickshot....also it will help tremendously to learn to do jetting yourself....it is easy. :thumbsup:

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I have it on my 06, but i never even started the bike without it - had it on my 03 and moved it over when i upgraded.... i have no idea what it would be like with it off, but hey i figure it cant hurt...yeah, that wasnt helpful, but i can tell you it hasnt made it bad :thumbsup:

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Everything about carbs is easy! the quickshot is just 3 screws, and don't loose the spring or seals.(Personally I don't think the quickshot is worth the money, but if you find one for cheap, then it might be o.k.)

Jetting is one bolt (carb drain) and the use of a flat head screw driver or small socket (depending on what jet your working on)

All you need to do is take a look at your yamaha book, take your time, and remember if it's difficult - your doing something wrong.

P.S. Listen to gray racer, he knows his sh!t

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Yuo need to turn your air fuel mixture screw in a quarter or out a quarter and see witch way it runs better then go from there with turning the screw the way it rund better and run a bigger pilot jet to go up one size and with the bogging you need to get the boysen accerator pump cover on it and that should do it

-Thomas-

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Yes but know you ned to buy an aftermarket fuel screw but do not get the MSR one it dosnt fit right ive had problems with it try the zip tye racing fuel screw

-Thomas-

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Yes but know you ned to buy an aftermarket fuel screw but do not get the MSR one it dosnt fit right ive had problems with it try the zip tye racing fuel screw

-Thomas-

The storm racing fuel screw has two O rings which keeps garbage out of the threads and keeps the screw from falling out.

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Is there an easy way to get access to the fuel screw without taking the carb off?

You can get it out without moving the carby by using a short, small screwdriver. If you don't want to buy an aftermarket fuel screw, or can't get one soon enough, you can super-glue a terminal to the end for adjusting. I've never had one come unstuck, but just in case it does and you need to use a screwdriver, don't allow glue in the slot at the end of the fuel screw, just put glue around the outside. http://members.optusnet.com.au/~bensuhard/mypic4.jpg

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Yes but know you ned to buy an aftermarket fuel screw but do not get the MSR one it dosnt fit right ive had problems with it try the zip tye racing fuel screw

-Thomas-

I've had a MSR in my 06 for 9 months, no issues at all with it :thumbsup:

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hey I bought the fmf jet kit to get my bike better. Should I just change pilot or both and is this shit hard. If anybody has any carbs for dumbasses links please include. I have no idea about the fuel screw this is my 1st 4 strokre and I am trying to learn. Been on yz 250s way to long. I just dont trust my dealer. If the Fmf jet kit is junk please let me know it will go back. Just want to get that off the throttle popping out a little i dont mind but damn this thing is nuts. It hasnt been jetted and also has the white bros mx4, thanks

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I also called white bros and they said leave it stock but i know it shouldnt be popping this damn bad. what would u guys do

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Go richer on your fuel mixture screw 1/4 - 1/2 turn. Call W/B and ask what the settings should be on the carb.

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hey I bought the fmf jet kit to get my bike better. Should I just change pilot or both and is this shit hard. If anybody has any carbs for dumbasses links please include. I have no idea about the fuel screw this is my 1st 4 strokre and I am trying to learn. Been on yz 250s way to long. I just dont trust my dealer. If the Fmf jet kit is junk please let me know it will go back. Just want to get that off the throttle popping out a little i dont mind but damn this thing is nuts. It hasnt been jetted and also has the white bros mx4, thanks

You can just change the pilot jet for now, but changing the other stuff isn't difficult, it just takes a bit of time.

To change the pilot, you'll need to remove the seat and tank, the top engine mount brackets(undo and remove five bolts), unscrew the "hot start" assembly and pull it out(put some grease on the plunger while you've got it out 'cause they can sieze up), tilt the carby and unscrew the large plug on the bottom of the float bowl(or remove the float bowl).

You can change the main jet while you're there, but you may have to remove the float bowl to get at it(I can't remember), it's only four screws that hold it on.

To change the needle height/position, take the lid off the top of the carby and unscrew the needle's (securing)bolt to get to it. Twist the throttle to raise the slide to make it easier to get the needle out.

Your owner's manual has an exploded diagram of your carby.

Have you read this artcle about the fuel screw? http://www.motocrossactionmag.com/me2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=6E5BCFD99FD242B28032722A4D5D52E3

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