07 450,everyone Is Running Too Rich.


30 replies to this topic
  • Ga426owner

Posted May 23, 2007 - 07:47 AM

#21

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.:D


Correct me if I am wrong but the 06 and 07 share the same carb, and practically the same jetting specs :busted:
only difference - 06/07 have different needle jets - BTW the NFLR (07)is a better needle jet for the 06. The NPLR is stock.
The 06 must have a 45 or 48 pj to work correctly - this is what comes on a 07...
So once the 06 is jetted right - it is basically 07 stock jetting :ride:

Jetting is like women.....some work out, some do not.....some are better looking and less maintenance than others that are not as beautiful and/or high maintenance.........bad jetting = bad women.....which means my bike will run like crap and I am going through many breakups....some bike owners run rich and some run lean....jetting must be tinkered with, managed and recorded for spot on results. And results do vary :bonk:

  • grayracer513

Posted May 23, 2007 - 08:59 AM

#22

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?

There are several things that make the 4-stroke a different animal than the pingers. For one, the lube oil in a 4-stroke is distributed the same at all throttle settings, and just by the nature of the lube system, there's a lot more of it where it's needed. For another, the piston and rings don't have to deal with running over a set of gaping holes at high speeds.

But as to the question of air/fuel ratio, they are different in that regard, too. The first point to remember is that a two-stroke gets almost no benefit from the fuel characteristic called heat of vaporization, which is a major factor in keeping a four-stoke combustion chamber at a reasonable temperature. As the fuel enters the chamber it is vaporized, and in so doing, absorbs heat from its surroundings. Even a very lean mixture will do this nearly as well as a rich one. This happens in a two-stroke, too but it happens more or less entirely in the crankcase, where it is much less important. This is one of the reasons that fuel needs to be blended differently for different applications. The vapor rates, etc., can be adjusted to address this to some extent.

In order to completely burn a pound of gasoline, and have no leftover fuel or oxygen, you need 14.7 pounds of air. That ratio, 14.7:1, is the "stoichiometric", or chemically balanced, rate at which fuel and air must be mixed in order to completely burn. Because a certain amount of fuel will never be burned in any given power stroke, the best power is usually produced in a 4-stroke at about 13.6:1. Modern cars run as lean as 16:1 and leaner under light loads.

When the mix is correct, combustion takes place, and there is "no" leftover fuel or air (ignoring the unburned fuel that results from various inefficiencies). If it's too lean, the one obvious problem from a performance standpoint is that you could have gotten more fuel in the engine, and thus, more power out of it. From a mechanical viewpoint, yes, the temperature may run a little higher, but it isn't a problem when using good fuel blend unless the cooling system isn't able to deal with it, and these days, it usually is. As long as the ignition timing doesn't contribute to the onset of detonation (starts as "pinging", but gets much worse), there is no real worry in a 4-stroke, because the performance will deteriorate to the point of misfiring before it causes any damage.

Rich mixtures, OTOH, leave a lot of fuel leftovers simply because the available oxygen was completely used up before it all got burned. This extra fuel forms carbon deposits in the combustion chamber and on the exhaust valves, contaminates the lubricating oil when it is forced past the rings, and in extreme cases, can wash out what little oil there really is on the rings and interfere with their ability to seal. The carbon deposits can become bad enough that they create "hot spots" that will become sources of pre-ignition, which will cause detonation. Carbon can also pack around the top ring and interfere with sealing.

From a performance standpoint, rich mixtures don't burn hot enough to generate good power, and, of course, if the mix is much too rich, the engine will blubber and miss.

If you were to look at the range of jets that would allow an engine to run without misfiring either from being too rich or lean, you would find that the ideal power mixture would fall nearer the lean limit than the rich (probably about 30-40% up from lean). It is this tolerance of being over rich that so often fools people into jetting richer than they should.

  • grayracer513

Posted May 23, 2007 - 09:11 AM

#23

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

Even if you end up having to tip the carb, yes, you can get it out by using the bottom plug. Getting the new one back up and in that way can try your patience, however, unless you use a screwdriver with a centering pin, or one that fits the jet slot snugly. You can use a piece of wire, also.

Correct me if I am wrong but the 06 and 07 share the same carb, and practically the same jetting specs :ride:

There are apparently some internal differences, or Yamaha rethought their overall jetting, as the '07 was delivered with a larger pilot, a half-step richer needle, and a two steps leaner (160 vs. 165) main jet. I'm sure there is something to it.

  • Ga426owner

Posted May 23, 2007 - 09:50 AM

#24

There are apparently some internal differences, or Yamaha rethought their overall jetting, as the '07 was delivered with a larger pilot, a half-step richer needle, and a two steps leaner (160 vs. 165) main jet. I'm sure there is something to it.


Yami rethought it alright, the jetting that we all (or 95% of us) did to our 06s to get them to run right:p

  • grayracer513

Posted May 23, 2007 - 10:22 AM

#25

Yami rethought it alright, the jetting that we all (or 95% of us) did to our 06s to get them to run right:p

I don't think I recall that very many people on this board are running a 160 main jet. :)

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  • Ga426owner

Posted May 23, 2007 - 10:59 AM

#26

I don't think I recall that very many people on this board are running a 160 main jet. :)



agreed...it does not work well on my 06 for my altitude/humidity/temps

  • bigred455

Posted May 23, 2007 - 01:14 PM

#27

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



Yep,it is directly behind the main very simple,putting the pilot back in is a tad harder,but you get use to it. If you have trouble putting the pilot back in,lean the bike on the right side,so gravity doesn't make it drop before you put the screwdriver on it. I have it down packed:p in and out in 3 minutes with the bike upright on the stand,the main 1 minute.Jetting 4 strokes(Keihin) is very simple compared to 2 strokes,ACCESS WISE.

  • rexbond007

Posted May 23, 2007 - 08:56 PM

#28

I had a 48 pilot and 165 main jet in for winter, now that it's warmed up to 20 + Celsius , i went back to stock Jetting @ 45 pilot and 160 mj. 1 1/2 turns out on fuel screw. now there's just a slight crackle on decel. and starts first kick. if it drops in temp, it comes out to 2 turns out. I did the Von beard mod with the O-ring and eliminated my low end bog.
i do have to agree a hand full of bikes out there are a little on the rich side. but no two bikes run the same, we all live in different areas west cost to east , moisture, altitude, barametric pressure, ambient temp is all factored into the running of these high performance competion bikes. like earlier mentioned they are forgiving, but until they cannot forgive no more..and bogging starts. In my earlier days i'v been in the bush on a hot hot day, high altitude... and bog... first ,second ,third gear. Took the bike to yami dealer and they re-jeted it all the way down in jets including the needle, and said hey man your running rich.(01 WR 250)

  • bigred455

Posted May 24, 2007 - 12:49 PM

#29

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


I believe you have a 06 450,I am talking about the 07,Read again.:bonk:

  • Jessthro

Posted May 24, 2007 - 01:54 PM

#30

stock my bike ran horrible. since then i put in the 170/48 combo, on the fly fuel screw and quickshot. teamed up with a pipe and filter it runs like a champ esp. in the dunes.

  • runester

Posted May 24, 2007 - 04:08 PM

#31

I have a question about all these jetting theories...First of all I am running a 48 pilot and a 168 main per Burns recommendation but also heard it from Zip-ty as well ( just got my carb back Wed.) I had a pretty long talk w/Steve there about fuels, jetting etc. I ride So Cal tracks and Dessert and he said just drop the pilot when it heats up, am new to 4 strokes but my bike runs PERFECT with this combo I havent had it out yet w/the ZT mod but have had it on the track stock, and w/the 48/168 combo and stock it did NOT run well on the track, it was embarrasing to be honest though there was a 4 stroke learning curve in my case it was also the machine NOT responding well, ALL the problems went away w/the re-jet. My question is my re-jet was based on Burns advice and his advice was based on a dyno he did so does the dyno care whether the bike is running rich? If the dyno dictates the optimum combo is a 48/168 how does this corrolate with overall efficient combustion?
Rune





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