I have a slight bog on my 06 450f after jetting.

[jason07]

I followed the jetting guide and upped my pilot jet to a 48 and my main jet to a 170. I live in Texas and am about 400ft or so. I also installed a pro circuit fuel screw and have it turned 2 turns out. I tried it turning it more or less in oother directions but it really did not affect anything. The bike runs great but it just has a little bog off idle and that is it.

I really wish the mechanic at my shop was working today but he is sick. So I have to bother you guys with this question.

Any suggestions would be great

[maddogyz250f]

The main jet shouldn't impact the off idle bog. If you are testing in nuetral, it is very hard to tune the bog out. If it bogs under load, some other areas to experiment with are needle clip position, leak jet (usually smaller), A/P squirt and idle speed. Buy an air density gauge so you can record the air density when your jetting is working well. As weather and altitudes change, the gauge will help you with jetting changes. In general, a 3% change in realitive air density equals one jet size. Keep a log of jetting and gauge readings and you will build, over time, a database of perfect jetting specs.

[yami racer]

Jason,

I have this slight off idle bog also...I am getting the GYTR Fuel Screw this week as I think sticking with the OEM will work best. I am racing on Saturday and should have everything in on Friday night so I will try to let you know..

I have the 170 main 48 pilot and 2.5 on the screw now but that worked great for 35 degrees. This weekend is supposed to be 65 degrees and I am thinking about going back to the 165 main with a 46 pilot but not sure just yet (around 600 ft). You could also try just adjusting the idle up and that will take the bog out some...

[jason07]

I guess I can try adjusting the idle screw. I will be interested to know how your race turns out this Friday night. Let me know about your bog.

Thanks

Jason

[SM421]

I don't have an answer but, I am not totally happy with my jetting either (48/170). Mine still coughs occasionally on acceleration out of turns.

I have to say that while I think the '06 YZ450 is the best handling bike I've owned, I am a bit disappointed at having to deal with jetting issues. This is the one area where I think the CRF450 has the Yamaha beat hands down. My '03 was flawless in the jetting department and the same is true with my buddies '05. The Honda works great in almost any condition with stock jetting.

With all of us Yamaha customers having carburetor/jetting issues with the '06 I hope Yamaha is listening.

[aford541]

I don't have an answer but, I am not totally happy with my jetting either (48/170). Mine still coughs occasionally on acceleration out of turns.

I have to say that while I think the '06 YZ450 is the best handling bike I've owned, I am a bit disappointed at having to deal with jetting issues. This is the one area where I think the CRF450 has the Yamaha beat hands down. My '03 was flawless in the jetting department and the same is true with my buddies '05. The Honda works great in almost any condition with stock jetting.

With all of us Yamaha customers having carburetor/jetting issues with the '06 I hope Yamaha is listening.

Try this it worked for me.

[Ga426owner]

I don't have an answer but, I am not totally happy with my jetting either (48/170). Mine still coughs occasionally on acceleration out of turns.

I have to say that while I think the '06 YZ450 is the best handling bike I've owned, I am a bit disappointed at having to deal with jetting issues. This is the one area where I think the CRF450 has the Yamaha beat hands down. My '03 was flawless in the jetting department and the same is true with my buddies '05. The Honda works great in almost any condition with stock jetting.

With all of us Yamaha customers having carburetor/jetting issues with the '06 I hope Yamaha is listening.

Every Yamaha MX bike since 1998 for me has had to be rejetted - this is a norm for almost every bike out there. Hondas may be better in that department. All of us yami customers do not have issues with the jetting. It seems to me that most issues are for people at the sealevel to 900ft altitude. So use the 170/48 as the starting point and jet accordingly for the lower altitudes. Lower altitiudes will increase leaner conditions. The 170/48 works perfect for me with no bog what so ever for 900-2000ft. Ask Burned for his spec at this lower alttitude.....or try this AP mod as many of CRF owners are now doing...YOT has been using the wire method for a couple of race seasons...ask them how if you need help.

[SM421]

Every Yamaha MX bike since 1998 for me has had to be rejetted -

I would have to agree with you on this point. As I recall, my '99 YZ400, '04 YZ450 and now '06 YZ450 all had/have a bog and needed re-jetting.

It is odd that none of the magazine tests I have read mention a bog or the need to re-jet the '06.

[bushman06]

Hey Jason,

I also live in Texas mate, and have had some issues with jetting. I have the 170 main and a 52 pilot with a boysen ac pump and full pro circuit system. Fuel screw 2.5 turns out.

I tried a 48 pilot and my bike had a slight bog, but more importantly had a major problem starting, hot and cold. I put a 50 in there and was slightly better, finally settled on the 52.

Now the bike bloody rips! No probs starting either!

My mate who bought the same bike as me on the same day is running 170 main and 48 pilot with 2.5 turns out? All I know is each bike is slightly different and you will just have to play with it to get it right.

Good luck

[yami racer]

I am going to head this over to the jetting forum for those of us at 300-900 feet..

[Ricky450F]

Damn this is frusterating.. I just bought a new 06 450f and its doing the same thing and I'm at sea level (San Diego). Does everybody's bike backfire too when you let off the throttle? Mine loves to backfire when engine braking or letting off.

[Ga426owner]

At sea level go smaller on the pilot from a 45 to a 42 or 40. This seems to be the advice from the jetting experts....

[aford541]

At sea level go smaller on the pilot from a 45 to a 42 or 40. This seems to be the advice from the jetting experts....

There are many influences on Jetting, generally the closer to sea level you are the larger jet you need unless the humidity and or temperature is high.

Check out this thread from Burned that explains it.

My 06 450 has a 48 / third clip / 170 main and it runs great on ELF LMS fuel at 1500 to 3800 feet, I could lean it out and make another HP or so but I doubt I would ever go to a 42 again.

ELF LMS is like U4 it is oxygenated and requires a little more jet.

[NYMXer]

Adding a PowerNow will help too. It goes between the carb and engine to smooth out the air turbulances. It helps enough to notice, esp at low rpm's. ?

[aford541]

Adding a PowerNow will help too. It goes between the carb and engine to smooth out the air turbulances. It helps enough to notice, esp at low rpm's. ?

Oh I have one one of those on the front and back also.

[RoughR1der]

At sea level go smaller on the pilot from a 45 to a 42 or 40. This seems to be the advice from the jetting experts....

its the other way. he needs to go bigger....48. 42 is stock, that would work at 5k'+ the way this bike runs stock @ seal level.

[Ga426owner]

its the other way. he needs to go bigger....48. 42 is stock, that would work at 5k'+ the way this bike runs stock @ seal level.

Well that is what I thought too originally for lower altitudes - keep in mine - sealevel to 900ft - But the jetting experts say smaller pilot jets - 40/42 - calibrate the fuel screw 1.5 -2.0 turns out

Again for 900-1900ft, I am at 48/170 combo runniing only U4 fuel....bike runs like a champ no popping period. ?

gotta go ride.....

[RoughR1der]

i'd like to see the post(s) about going smaller for this model. i think you might have gotten confused. i havent seen anything about going smaller since it's soooo lean already. never the less, i have been riding 5k' w/ the 48/170 and it works better than stock jetting @ sea level, although since i ride higher alt. i might go back to stock (42/165) and see how it works.