bansheefourseven Posted November 13, 2006 Report Share Posted November 13, 2006 I just got some paul turner mid range pipes and had a question. Im running a gytr twin air filter (looks like stock replacement with full airbox lid and all) I am going to be installing these pipes in a few days. What do I need to do as far as rejetting? what mains and others need to be changed? I live in michigan so 400-800 feet above sea level roughly. trail riding and an ocasional dune trip. Any help would be great Quote Link to comment Share on other sites More sharing options...
BansheeDan Posted November 13, 2006 Report Share Posted November 13, 2006 I just got some paul turner mid range pipes and had a question. Im running a gytr twin air filter (looks like stock replacement with full airbox lid and all) I am going to be installing these pipes in a few days. What do I need to do as far as rejetting? what mains and others need to be changed? I live in michigan so 400-800 feet above sea level roughly. trail riding and an ocasional dune trip. Any help would be great i am also in michigan...... i have 280s in mine with toomey t5s and a k&n but thats with no airbox lid too..... i would say with youre set up try 260's and go from there Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 13, 2006 Report Share Posted November 13, 2006 Depending on where you're at...and how soon/often you plan on riding...you might want to go with 280s and work your way down. My Fellow Michigan brothers, it is starting to get cold out...so, time to richen them up!! Otherwise, yeah...260 is probably about right with a box and lid... Quote Link to comment Share on other sites More sharing options...
400ccStroker_shee Posted November 14, 2006 Report Share Posted November 14, 2006 Depending on where you're at...and how soon/often you plan on riding...you might want to go with 280s and work your way down. My Fellow Michigan brothers, it is starting to get cold out...so, time to richen them up!! Otherwise, yeah...260 is probably about right with a box and lid... I thought the bike runs richer when it gets colder outside, well at least thats what the jetting diaghram says in my 2004 yz250 owners manuel. My owners manuel says temp- hot = leaner cold= richer altitude- higher=richer lower= leaner please help me because now I'm confused. Quote Link to comment Share on other sites More sharing options...
400ccStroker_shee Posted November 15, 2006 Report Share Posted November 15, 2006 I thought the bike runs richer when it gets colder outside, well at least thats what the jetting diaghram says in my 2004 yz250 owners manuel. My owners manuel says temp- hot = leaner cold= richer altitude- higher=richer lower= leaner please help me because now I'm confused. bump Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 15, 2006 Report Share Posted November 15, 2006 Your manual is telling you how to adjust the jetting for the temperature, not how it effects the bike. Trust me on this one. When it gets colder, you must richen up the jetting to compensate for it, and when you go higher in elevation, you must lean it out. Here is an excerpt from the Jetting FAQ on top of this page, taken from Dirt Wheels: For our first example let's say we find a new riding area WAY up in the mountains. Our jetting is dialed in for our usual riding area which ranges from sea level to 1500 feet. Our NEW riding area starts at 4000 feet and goes up from there. Going to a higher elevation will require will require a jetting change but which way? Like our fuel density, air density can also change. Higher elevations have less air density then lower ones. At high elevations our engines are getting less air, so they need less fuel to maintain the proper air/fuel ratio. Generally you would go down one main jet size for every 1750 to 2000 feet of elevation you go up (info for Mikuni carbs). If you normally run a 160 main jet at sea level you would drop down to a 140 at 4000 feet. Something else goes down as you go up in elevation is horsepower. You can figure on losing about 3% or your power for every 1000 feet you go up. At 4000 feet your power will be down about 12%-even though you rejetted! For our second example, let's say we are still at our new 4000-feet elevation riding area and a storm comes in. We head back to camp and ride it out overnight. The next day there's a foot of snow on the ground the skies are clear and it's COLD! Aside from getting the campfire going and making some coffee you should be thinking about jetting again! Cold air is dense air and dense air requires bigger jets. If the 140 jet ran good the day before you will need a bigger jet to run properly today. If the temperature is 50 degrees colder than it was the day before you can actually go back to your sea level jetting, a 160 main jet! If you don't rejet you can kiss your assets goodbye when you rebuild the seized engine. Air temperature makes that much difference! Quote Link to comment Share on other sites More sharing options...
Bill Posted November 15, 2006 Report Share Posted November 15, 2006 Nice explanation Dave. :thumbsup: Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 15, 2006 Report Share Posted November 15, 2006 Thanks, but I can't take credit for that LONG paragraph...I just copied and pasted it from the jetting faq up top on one of the stickies. (YOu all know I like to type...but, I took the shortcut this time...LOL ) :beer: Quote Link to comment Share on other sites More sharing options...
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