Whats the deal with '06 YZ450 Jetting

I have spent a lot of time searching this forum for tips and explanations on the problems with the '06 YZ450 jetting being too lean. I think I am more confused then when I started. Why would these engineers design a technically advanced bike and sell it with jetting, that according to what I have found here, no-one uses. I want to take care of a brand new $7000.00 purchase but am not really sure what the correct route to go is.

I know that members here come from every part of the country with temperature and altitude all being different. I ride in southern California where the temp is usually between 60 and 100 and altitude under 4000 feet. Would the 170 main and 48 pilot be the correct choice for these conditions or should I try a different choice? I know this subject gets beaten to death, but for some this is a whole new animal to deal with, so I appreciate any helpful info.

I live in SoCal and ride all the tracks and run that jetting. It is perfect for the 06' YZ450.

I have spent a lot of time searching this forum for tips and explanations on the problems with the '06 YZ450 jetting being too lean. I think I am more confused then when I started. Why would these engineers design a technically advanced bike and sell it with jetting, that according to what I have found here, no-one uses. I want to take care of a brand new $7000.00 purchase but am not really sure what the correct route to go is.

I know that members here come from every part of the country with temperature and altitude all being different. I ride in southern California where the temp is usually between 60 and 100 and altitude under 4000 feet. Would the 170 main and 48 pilot be the correct choice for these conditions or should I try a different choice? I know this subject gets beaten to death, but for some this is a whole new animal to deal with, so I appreciate any helpful info.

I ride in Phx and that set up is perfect for me.

I have that jetting in my bike now....I live and ride in Alaska..... weird as it sounds it worked perfectly today and it was chilly/windy (high of 40). Stock jetting (42 pilot and 165 main) was very lean in the same temps the weekend before. I honestly have zero issues now with popping...starting...or hauling ass. The jetting seems dialed....I am just working on how to stay on top and ahead of the bike now!!!

Seriously, it is the type of bike that raises your limits as a rider. Holy mother of god this bike is sweet!

I'm running 48/168 and it's perfect for me. Starts easy and never pops under decel. I almost never need the 'hotstart' and I can start the bike in gear. :thumbsup:

ok so far heres my experience.. in NY 50's bike ran absolutely perfect with choke on . so i take the stock jetting and go to 170 / 48 and 2 turns out seems a lil loagie and still popping slightly and now a very minor bog turning out to 2 1/2 stops popping .. but this set up is definately not as crisp as stock with choke out.. my next test will be lower main . and raise needle one clip .. any thoughts ?

I'm 48/168 and 2 turns out w/ my needle on the middle clip. Runs perfect. No bog, no miss, no start issues. I'm happy. :thumbsup:

dooweb2, try my settings as I am from NYS too.

ok Ill try that .. actually that was my next set up anyway lol thanks ..

Seriously, check your whole carb for casting issues. Friend of mine was contacted by factory and said there has been some casting issues in some of the 450 carbs

For a stock 06 YZ the 48 pilot is simply too rich. If you have eliminated all popping on decel then you are too rich for sure. Best bet is the fuel mixture screw between 2 and 3 turns out, a 45 pilot jet and the needle clip +1 richer (5th position) stock main. This setup hits hard from 0 to 4000 feet and temp range from 60 to 90 deg F. Some may say the 48 is the best setup but all it really does is over richen the pilot circuit and richen up the the beginning portion of the needle.

For a stock 06 YZ the 48 pilot is simply too rich. If you have eliminated all popping on decel then you are too rich for sure. Best bet is the fuel mixture screw between 2 and 3 turns out, a 45 pilot jet

This is what I have been told by a few mechanics 48 is too high stick with a 45

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