yz85 oil out of silencer

Discussion in 'Pit Bikes & Mini's' started by severemxaddiction, May 14, 2011.



  1. severemxaddiction

    severemxaddiction Rookie DRN Member

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    when i ride, and this happened on my 65 too, oil runs out of my silencer.....is this normal? i havent seen it before, and i always use Amsoil synthetics......

  2. Patman

    Patman Pantless Wonder

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    It's "normal" if you are not properly jetted no matter what premix oil you use. You will need to repack your silencer after getting it dialed in as it's saturated.
  3. gripinrip

    gripinrip Rookie DRN Member

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    So would you go up in jetting or down?
  4. gripinrip

    gripinrip Rookie DRN Member

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    My 7 yr old son race a KTM 50 Sr and will be racing a KX65 in hare scrambles. Could use any and all advice!
  5. _JOE_

    _JOE_ Subscriber

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    It's harder to tune the 50s as you can't ride them yourself to feel for changes. You have to rely on sound, temps and smoke/spooge. Excessive smoke and /or oil out the exhaust (spooge) points toward rich jetting or lack of air flow. Ensure the air filter is clean and repack the silencer. Remove the carb and pull all the jets, floats and choke assembly out. Use aerosol carb cleaner to spray through all the jets and carb body passages then blow everything out with compressed air. Write down what main and pilot jet is in there and note the needle clip position. Check your stock jetting specs for comparison. Make sure the float valve is in good shape, both the "rubber" tip and it's seat in the carb body should show no wear. When you reassemble check that the float valve seats when the floats are parallel with bowl seating surface and the idle screw is turned in so that it just starts to lift the slide. Assuming your reeds, crank seals and top end are all in good shape you're ready to start jetting. Pilot circuit(air screw) first. Start at stock, usually 1.5 turns out from closed. Get it warmed up by RIDING THE BIKE for a little while. Once nice and hot hop off and turn the pilot screw in listening for the idle to break up. You may need to set the idle a little higher than normal. When the idle breaks up back it out a little, maybe an 1/8th turn. If it doesn't respond to air screw adjustment the pilot jet is likely too large. Go up a size and retest. Now you're ready for another quick test ride. Go out in 1/8th to 1/4 turn increments while riding at lower speeds and rpm and blipping the throttle to about a quarter turn. You should notice the difference in response as you go. When you're satisfied with the pilot circuit tuning move on to the main jet. I usually go pick up a couple different sizes in either direction. If you think it's rich go a size leaner (smaller number). Run it hard for a while on a fresh plug, 3/4 throttle up is main jet. Ideally you should have a plug viewer to look at the carbon ring at the base of the insulator, but you can usually tell if you're the ballpark by looking at the color down in there. Seat of the pants dyno will tell you if you're going the right way. It's easier to tell if you a large flat area to ride the bike. Once you're happy with the main it's needle time. Needle adjustments are usually the easiest to feel. One groove either way to start with and you should either feel it in the mid range, say 1/4 to 3/4 throttle or so. All this will take you an afternoon and about 20 or 30 bucks worth of supplies and jets, but once you're done you're bike will probably feel alot faster and run much cleaner and you'll have a feel for what incorrect jetting feels and sounds like. Once you tune a few bikes it'll all make sense and you'll be surprised how easy they are to get running well.....



    PS: Hows your 7 year old like the 50SR?
  6. gripinrip

    gripinrip Rookie DRN Member

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    50 sr

    The boy loves his Sr. He raced a Sr with the 10" front wheel then we bought him one with a 12" front wheel. Needless to say the 10" bike sits in the garage now lol. This past weekend we put him on a KX65 for his first ever hare scramble and he had a tough time. He can rip it in the fields but never rode in the mud. Being that we just got hit with Hurricane Sandy the course was pretty knarly. I had to use 6x6 blocks for starter blocks for him. He had troubles touching while climbing the steep hills and it did him in. Keep inmind he is only 47lbs LOL. He completed 2 laps on a 3.8 mile course though so it's the experince that helps. He starts racing a winter series (snow scrambles) this weekend on the 50.
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