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bigred455

07 450,everyone Is Running Too Rich.

31 posts in this topic

I am first to agree that with the same year model bikes, same fuel, same weather, and same elevation - the jetting can be slightly different. I see everyone is running a 168 main and 48 pilot. You are way off at sea level and higher with warmer weather. 65 DEGREES and below with the 160 main and 45 pilot (WHICH, BY THE WAY, IS STOCK) are on the money with mine. Rode in 80 degree weather and with the 160 main it was slightly rich. (power hit a slight wall, and didn't quite pull all the way through) In tight blip areas, the 45 was flaming out on me. This is what I have when above 70 degrees - 155 main, 40 pilot - and my motor sings.

I am not running pump fuel, the fuel I am running tends to run a little rich. Regardless, even running pump fuel, I cannot see how you guys are running clean with a 168 main and 48 pilot in warmer weather. The needle and clip position are both on the money. As far as these big companies giving jetting specs, do not take their word for it, do not even take my jetting specs - move those jets up and down and pay attention to the feel and sound of your motor.

One more thing, do not go by plug color on the insulator tip. You will be chasing your tail if that is how you are going to jet. In addition, set your accelerator pump timing by the manual. :)

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I am first to agree that with the same year model bikes, same fuel, same weather, and same elevation - the jetting can be slightly different. I see everyone is running a 168 main and 48 pilot. You are way off at sea level and higher with warmer weather. 65 DEGREES and below with the 160 main and 45 pilot (WHICH, BY THE WAY, IS STOCK) are on the money with mine. Rode in 80 degree weather and with the 160 main it was slightly rich. (power hit a slight wall, and didn't quite pull all the way through) In tight blip areas, the 45 was flaming out on me. This is what I have when above 70 degrees - 155 main, 40 pilot - and my motor sings.

I am not running pump fuel, the fuel I am running tends to run a little rich. Regardless, even running pump fuel, I cannot see how you guys are running clean with a 168 main and 48 pilot in warmer weather. The needle and clip position are both on the money. As far as these big companies giving jetting specs, do not take their word for it, do not even take my jetting specs - move those jets up and down and pay attention to the feel and sound of your motor.

One more thing, do not go by plug color on the insulator tip. You will be chasing your tail if that is how you are going to jet. In addition, set your accelerator pump timing by the manual. :)

Well since you did not inform us of what type of "RACE FUEL" you are using, your results and the implication that everyone is too rich is ridiculous...I have tried your miraculous combo of 155mj and 40pj here in the SE and it is no good....sorry dude :ride:

Way too lean....to be precise for temps in the 65 - 80 range. Maybe for desert conditions in the 105-112range though :bonk:

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I just read an artcle in the new drtbike mag, about a KTM that they put a bunch of insturments on and found the very same thing. They ran a 140 or 150 as baseline. that bike comes w/ a 168 as well. They changed needles though. I agree that you can't speak for everywhere, but an AF ratio meter doesnt lie. I have some of there stuff on one of my bikes and Im thinkin about trying there jetting now.

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im at sea level, in 85 degree weather, and my 07 450 was running waaay too lean.

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My '06 runs very well with the 45 pilot and either a 165 or 162 main. I have to agree that people running 48/170 combos are probably running richer than necessary by a significant amount.

One reason they do is the obsession with eliminating decel backfiring. IMO, if a YZ450 doesn't crackle a little on decel most of the time, it's too rich on the pilot.

Another reason is the obsession with getting the bike to withstand an idle-to -WOT throttle snap. It may be necessary to improve on a bike that is too prone to stumble off-idle (it was on mine), but beyond a functional level, it just isn't required for anything you really do. Learn to roll the throttle rather than snap it.

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I went riding last weekend in the California desert. The temperature was in the low 90's and the elevation is right around 3000 ft. My bike ran perfect with a 48/168 combo. I really don't know what you are talking about.

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My '06 runs very well with the 45 pilot and either a 165 or 162 main. I have to agree that people running 48/170 combos are probably running richer than necessary by a significant amount.

One reason they do is the obsession with eliminating decel backfiring. IMO, if a YZ450 doesn't crackle a little on decel most of the time, it's too rich on the pilot.

Another reason is the obsession with getting the bike to withstand an idle-to -WOT throttle snap. It may be necessary to improve on a bike that is too prone to stumble off-idle (it was on mine), but beyond a functional level, it just isn't required for anything you really do. Learn to roll the throttle rather than snap it.

Gray,good reply,I also set up my pilot with a nice crack crack on the chop. The 07 comes with a 45 pilot and a 160 main,in warm weather on pump fuel this is very close,I shake my head that everyone is running with a 48 pilot and 168 main ON THE 07 in warm weather of course..The problem is they have it in there head it runs good and it probably does to them ,but with jetting you never know until you move them jets and you can get better.TRIAL AND ERROR!

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I just read an artcle in the new drtbike mag, about a KTM that they put a bunch of insturments on and found the very same thing. They ran a 140 or 150 as baseline. that bike comes w/ a 168 as well. They changed needles though. I agree that you can't speak for everywhere, but an AF ratio meter doesnt lie. I have some of there stuff on one of my bikes and Im thinkin about trying there jetting now.

Let us know how you made out.:)

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The 48/168 Combo is what Zipty recommended to me a week ago. The bike runs great with no hesitation or bogs and pulls cleanly all the way through the power band. When a winning race team gives jetting advice, how can you go wrong? I mean, they do this kind of stuff everyday.

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I don't jet for absolute maximum hp. I jet for good overall running behavior across a wide variance in temps. Here in New England, it's not uncommon for morning temps to be 50F, then jump up the 80 by afternoon. Changing the pilot jet is a friggin PIA in the YZF's. So I jet for a compramise of all expected temps. Right now i'm jetted 48 and 165. I am probably a tad lean in the morning, and a tad rich in the afternoon. Bottom line is my bike starts, idles, accelerates excellent with minimal poping, NO off idle hesitation, and really pulls hard right to the rev limit. All this with NO needed jet tweaks.....

Riding a bike that's jetted too lean on the pilot can be very frustrating with a bog. Riding a bike that's jetted a tad rich is far easier, as all you've done is lost a slight bit of throttle response (and I mean a SLIGHT bit too). So IMO it's better to jet a tad rich. The engine will also run respectively slightly cooler if you are jetted richer also.

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The 48/168 Combo is what Zipty recommended to me a week ago. The bike runs great with no hesitation or bogs and pulls cleanly all the way through the power band. When a winning race team gives jetting advice, how can you go wrong? I mean, they do this kind of stuff everyday.

Same here.

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The 48/168 Combo is what Zipty recommended to me a week ago. The bike runs great with no hesitation or bogs and pulls cleanly all the way through the power band. When a winning race team gives jetting advice, how can you go wrong? I mean, they do this kind of stuff everyday.
Same here.

Same here also....

who knew all this time we were running way too rich... Maybe it's his special NJ gas...

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Changing the pilot jet is a friggin PIA in the YZF's.

Changing the pilot is quite simple, I made a 90 degree screwdriver,just drop the 17mm drain plug and your there. There is plenty of room between the cases and the bottom of the carb with 4 strokes.Just make sure you have the right size screw driver for the pilot before you cut and bend.:)

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Same here also....

who knew all this time we were running way too rich... Maybe it's his special NJ gas...

Jetting specs by major companies are not going to give perfect jetting specs for the large mass,they will be on the conservative side,THINK ABOUT THAT .:) 168 main in warm weather along with a 48 pilot at sea level with even pump fuel,on the average is too rich.THIS IS THE 07 450 NOT THE 06.I have the 07 do you? 20:1 these jetting specs you are getting for the 07 are confused with the 06. I do not take anyones jetting specs,I put the time into it,I trust myself! The only thing that matters is, the owner of the bike is happy,even though he or she is running rich and doesn't even know it.:ride:

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These jetting specs are for the 07. Do you really believe that your jetting specs v.s mine would make that much difference? I just believe that running a bit to rich is a lot better then running lean.

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By the way, on my XR650 I used to run a 175 main year around. Bike always ran the same. And when you go riding every weekend, you can tell!

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These jetting specs are for the 07. Do you really believe that your jetting specs v.s mine would make that much difference? I just believe that running a bit to rich is a lot better then running lean.

DesertRacer,I am assuming you ride a lot of desert,I also would jet on the fat side of the main.I know riders would think different because of the heat in the desert,but full throttle running, majority of the time like in the desert,you are playing it smart.:) For your type of riding, no, I do not believe my jetting compared to yours will make that much of a difference.I will say on a MX TRACK yes,believe it or not if you are rich enough on the main,not only does full throttle get dull,but it does bleed down into the mid. You are a total different story and I agree with your thinking.:ride:

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I don't. 4-strokes can tolerate being jetted very lean or, frankly, ridiculously rich and still run reasonably well. As a result, there are a large number of bikes dashing around with oversized main jets in them simply because they still ran good with the bigger jet so it must have needed it, right? However, the gains you get from getting the jetting right on the money, or even close, are quite real.

There is considerably less risk to a 4-stroke from being jetted marginally lean than there is to a two-stroke, and not only because the fuel in the latter case carries the lube oil. At the same time, there is more risk to the engine in the long term from being too rich than you might think. Fudging a little rich doesn't really provide any protection from engine damage, quite the opposite, in the extreme, in fact, and it certainly does cut back on efficiency.

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Bigred, sometimes I have to remind myself that not everyone rides desert! What you say about running richer on an MX track makes sense to me. I can see where that can be a problem.

Grey, I know that seizures on a two stroke with lean jetting can be likely, I have toasted my share of bikes. I also know that 4 strokes last a lot longer because the piston is always in its own oil bath. However, won't lean jetting on a four stroke cause unnecessary heat build up which can cause premature engine wear? When I ride in the desert, I do a lot of WOT riding and the fatter main jet just gives me peace of mind. Am I still thinking like a two stroke owner? :) I have to remind myself that those days are over!

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Changing the pilot is quite simple, I made a 90 degree screwdriver,just drop the 17mm drain plug and your there. There is plenty of room between the cases and the bottom of the carb with 4 strokes.Just make sure you have the right size screw driver for the pilot before you cut and bend.:)

No kidding?!!? You can drop the pilot jet through the carb drain plug??????:ride: Thanks for the tip!!! It took me like 3 hours yanking the whole carb the last time......

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