06YZ450F Back Fires!


54 replies to this topic
  • pelted

Posted December 04, 2005 - 09:53 AM

#41

Broke in my 450 yesterday...Popping disapeared, she pulls hard throughout...no issues.

  • Wyatt

Posted December 04, 2005 - 01:18 PM

#42

The 45 pilot did the trick for me. I had about a 20 degree drop in temp from yesterday to today, so that throws a big kink into testing baseline settings.

Right now, I have the 45 pilot in and i am 2.5 turns out. It runs great, and I anticipate going in on the screw as temps get back to the 80-90 range.

The bike still rumbles on decel, but I have always found that my bikes run the best when they still pop a little on decel. Now it has a slight poping on decel and is nothing like it was before. It is now right where I want it. With the 42 pilot, I had some pretty intense backfiring.....the kind that can take the packing out of a silencer if you let go on.

The bike starts very easily and runs strong. It pulls so smoothly. My '04 felt faster, but I know this one is just as fast. It just pulls really smooth.

I can't wait to get to the track this week to let it stretch its legs. Break in is over!!!

  • DPW

Posted December 04, 2005 - 01:32 PM

#43

I live in the DFW area also.
I tried the 45 pilot, helped a little but did not stop the popping going to try a 48 this week.


Where in the DFW area did you find a 45 pilot?

  • DPW

Posted December 04, 2005 - 01:38 PM

#44

The 45 pilot did the trick for me. I had about a 20 degree drop in temp from yesterday to today, so that throws a big kink into testing baseline settings.


I'm hoping the 45 will work for me too. It was about 30 degrees at Nocona today and the bike was kind of a pain in the old hind side to start first thing in the morning...some kid on a 80 heckled me for a bit until I got it started. I ended going a full turn-out from stock with the 42 and it ran great, but ....pop pop.. :applause:

  • Wyatt

Posted December 04, 2005 - 02:34 PM

#45

The 48 may work out, but that is a big jump from 42. It is worth a try, but I don't have one on hand. I can't beleive the jetting would be that far off. The 45 is doing the trick for me, and i think the 48 may be a bit over the top. Let us know how the 48 turns out.

  • matt116

Posted December 04, 2005 - 03:30 PM

#46

Where in the DFW area did you find a 45 pilot?


Pro Privater

  • DPW

Posted December 04, 2005 - 04:07 PM

#47

Pro Privater


Thanks and they are open Monday too, very cool.

Great shop, I've had quite a bit of work done there.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Norman

Posted December 04, 2005 - 04:53 PM

#48

I put in a 45 and it cleaned mine up. It started easier and seems to be a little crisper off idle. Im in Beaumont Tx, sealevel, mid 70's, very humid today.

  • Jimmmyzz

Posted December 04, 2005 - 06:04 PM

#49

Yes The Pilot jet. I took out the stock pilot which is a 42. I compared it to another 42 and it was alot smaller. Must have been drilled wrong from the factory.

  • DPW

Posted December 04, 2005 - 07:54 PM

#50

Quick question for you guys that changed the pilot....Do you have to remove the carb or is there enough room to tilt it to the side?

Thanks

  • ripntear

Posted December 04, 2005 - 07:58 PM

#51

Good question.
Just by looking at the photos, it looks like it is going to be very difficult to work on the carb.

  • Wyatt

Posted December 04, 2005 - 08:18 PM

#52

It can be done without removing carb. If you have replaced a pilot before and know what you are doing than you will be able to do it. You have to work blind, without being able to see what you are doing. The carb will not tilt enought to the side. I loosened the clamps of each side of the carb, tilted it as much as I could and worked blindly to get the 42 out and the 45 in. If you have done it before and know where the pilot is located, it is easy.

The carb is a bear to get to. Getting to the access plate on the throttle cable side is really tight. One of the toughest things to do is to get the airbox boot back onto the carb after subframe removal. With the frame design, there is no way to get your hands in there. I had remove the top shock mount bolt and push it to the side in order to get the airbox boot on. A few things are tougher to get at on this bike, but I think the positives out weigh the negatives for sure.

  • aford541

Posted December 04, 2005 - 09:42 PM

#53

I figured it out! The jet was drilled wrong from the factory!! We took the jet out and compared it to another and it was a third of the size. We replaced it and the problem is gone.


That is cool, I must have changed 4 05 honda pilot jets to 45's I changed my 05 yz 450's to a 45 after porting the head and carb, I never thought to look at the opening on the jet.
Duh. Good catch!

  • Beanb1

Posted December 05, 2005 - 06:54 AM

#54

take the seat and tank off. remove the hot start from the carb. A little tight, but once the hot start cable and valve are removed the carb can be tilted to let the you see the bottom of the carb and all jets. Much easier to get the bowl off and back on.

Colorado, about 25 degrees yesterday. I found the 48 worked best, but as it warms up, I may change back to a 45.

  • DPW

Posted December 05, 2005 - 04:10 PM

#55

take the seat and tank off. remove the hot start from the carb. A little tight, but once the hot start cable and valve are removed the carb can be tilted to let the you see the bottom of the carb and all jets. Much easier to get the bowl off and back on.

Colorado, about 25 degrees yesterday. I found the 48 worked best, but as it warms up, I may change back to a 45.


Thanks, the hot start tip did the trick. I swapped in a 45 and set the fuel screw at 2.5 and there is still some popping on decel, but it's better and it was around 35 degrees when I tested it out.





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