Jump to content

yz rider

  • Content Count

  • Joined

  • Last visited

About yz rider

  • Rank
    TT Newbie

Profile Information

  • Location
  1. yz rider

    Mental Problems??

    i got mental problems
  2. Well mine starts to want to stall after half throttle and i was thinking full throttle is dealing with the main jet so i thought mabey its clogged. What you think?
  3. yz rider

    how do you approach doubles?

    What i do is dont let my arms turn the bars and just keep my eyes on the jump and hit it no matter what, usualy over jumping the landing because of fear of casing it.. When im heading for doubles i go fast up to em then let of the throtol for a secont and then gas it going up the double. Leaning back gets you to go farther off the jump.
  4. If a main jet is clogged will it still run and just have no power at full throttle? Or will it get no gas at all?
  5. yz rider

    popping on stock 06 yz450f exhaust

    Bottom end. Out is rich In is lean
  6. yz rider

    popping on stock 06 yz450f exhaust

    Adjust fuel screw first then if that dont fix it then pilot change
  7. yz rider

    boyesen quick shot with bk mod?

    whats the bk mod? i have the boyesen quick shot and i felt no gain.
  8. come on some one must have a repair manual.
  9. Whats the torque specs for the 6 bolts that hold the clutch springs in? 15lbs? Also will a 2000 yz426 inner clutch hub fit a 2002 426?
  10. Jetting a carb 1. Treat the symptom. Many people isolate the problem or can describe the problem but then treat it incorrectly. For instance, the bike/quad is not performing off the bottom, so they lean the main jet. If you’re having a bottom end issue, treat it first with the air screw and then possibly a pilot jet change. Mid range issues are going to be treated with clip position and full throttle issues with the main jet. 2. Needle clip adjustment is counted from the top. If your told to use the number 4 position, that’s the forth groove down. Moving the needle clip up lowers the needle, leaning the mixture, and vice versa. 3. Two strokes normally have an air screw, so out is lean. The air screw is going to be positioned before the slide. 4. Four stroke carbs normally have a fuel screw, so out is rich. The fuel screw is normally located under the carb, in front of the float bowl. 5. Altitude. The higher you go, the less air you have. Thus, if you go up and have less air, you need less gas, so lean the jetting. A good rule of thumb is lean1 jet size for every 3000 feet in altitude you gain. This is a conservative estimate and you can get added performance by checking the jetting and leaning even more. 6. Air temperature. The colder it gets the more air density you have. Think of air as a liquid which gets thinner as it gets hotter . Air is the same way. If it gets colder you need to add more fuel as you have more air. Your motor also makes more power as it gets colder. A good rule of thumb is every twenty-degree change in air temp is a main jet size change. 7. Don’t confuse speed with RPM when you’re working out a problem. Lets say the motor pulls good off the bottom but cuts out on top. That should be true in virtually every gear. Pulling good off the bottom does not mean running good in first and second gear only. Often a lean motor will run good in the lower gears but then start hesitating when revved hard in top gears. So when working on jetting issues, rpm description is the key. 8. Jet check. To do a main jet check the idea is to run the motor on the main jet and read the plug, isolating the main jet reading. To get a main jet reading, replace the spark plug with a new one. Ride the quad or bike for five to eight minuet s at a moderate pace, vary the rpm and shift up and down the gears. Once the motor is up to operating temp you can make a jet pass. Start in second gear and ride at full throttle through fourth gear fully revving it out in forth gear. With the throttle wide open in fourth hold the kill button down, pull in the clutch and stop. This is called a “plug chop”. Read the plug. With a flashlight and a magnifying glass, look at the porcelain part of the plug only. As you view the plug from the center electrode look down the length of the porcelain to its base. At this point their should be a dark, chocolate-colored smoke ring. Their was not sufficient time to thoroughly color the whole plug so the nose of the insulator will probably still be white as long as there is a visible dark ring at the base everything is ok. A more accurate way to read the plug is to saw off the threads at the washer. This allows you to look directly at the base of the porcelain, thus getting a very good reading. 9. For most trail riding and mx racing, a fourth gear plug chop is all you need to do. If you tend to run it flat out in top gear then make your jet pass/plug chop in top gear. Desert racing and wide open type riding will need a richer jetting than MX jetting. If you install a bigger carb on a 4 stroke, you should first consider whether it will benefit your model and riding style. Big carbs should be only put on MX,TT, drag racing and some sand riding applications. In trails and woods riding you want super throttle response, low to mid range torque, and gas mileage. Installing a big carb looses bottom end torque even if throttle response is good and costs fuel efficiency. Unless you are a pro level rider, large carbs should be last on your list of mods. Its ok to bolt a big carb and pipe on a 2 stroke, but on a 4 stroke its what inside that counts. High compression or big bore pistons, stroker cranks and cams are what make a 4 stroke perform. Another thing to consider is how much your head flows. Keeping a small port with high velocity is a key to getting performance out of a head. Most people think grinding a big port will flow more air, when in reality it makes for sluggish performance and a nightmare to correctly get your carb. It also will determine what size carb your engine needs. Each engine builder will have his own opinion on the amount of CFM a carb should flow over what your head should flow. A good rule of thumb for performance would be to have a carb that flows10-30 percent more than your port does at its highest lift. This is changing, however with the new style motors with their short rod-to-stroke ratios, lighter components inside the motor and multi-valve heads. VACUUM-STYLE CARB TRICKS. One of the hardest carbs to jet is the vacuum slide style carb. These are found on a lot of sport machines, including the z400, kfx400, dvx400, raptor, and even utility quads. They are great for throttle response. Unfortunately, they are not the best high- performance carbs. With a vacuum carb its best to not open up the airbox right away. Get your main jet set correctly first, which in most cases will be one to two sizes bigger than stock. After that, if the machine is backfiring when you let off the throttle, you can turn the fuel screw out one or two more turns than stock. After that if the machine is backfiring when you let off the throttle, you can turn the fuel screw out 1 or 2 turns than stock. If this does not get rid of the problem, you will have to go up on the pilot jet size and turn your fuel screw back (leaning it back down). Once you have these set, if you now want to open up the air box, you’ll often have to change the needle. Several companies offer jet kits with needled. As you open up the air box, you lessen the pressure that allows the slide to lift, so you need to richen the mid range up with a thinner needle. A thinner needle allows more fuel to pass into the intake tract. This can be a trial and error process of learning. TUNING BY DUCK TAPE. An easy way to jet this style of carb is by drilling as many 1-1/2 inch holes in the air box cover as you can. Put duck tape over all the holes except one. Then remove tape from the holes one by one until you get the machine to perform at its peak. The more holes you uncover, the more you will have to go up on the main jet. This is wear it gets tricky finding a balance between the richer needle, main jet, and the amount of air that make the machine run at its best. Taking the duck tape on and off will also be a way of re-jetting your machine from winter to summer (different temps) without having to start from scratch all over again.
  11. heres he shock. you can see it in the rear.
  12. i would say age 3-6. when i was 10 i had a hard time riding a kx80. i always jumped off it and dumped it cause i as to short. you should get him a pocket bike. they fly pritty fast though but you would be able to find out if he likes that stuff at a cheeper price