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Thread: Phazer main and primary nozzles

  1. #1


    Default Phazer main and primary nozzles

    Hello all. Just picked up a 90 phazer and was wondering if anyone could tell me the right part #'s I would need to switch out to get rid of the midrange lean spot. I'm located in MN and the sled is bone stock.

    Thanks

  2. #2
    Senior Member Stock
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    Yellowknife, NWT
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    If it is stock, clean carbs properly jetted, and has unmodified airbox in place there should not be a midrange lean spot. The lean midrange typically occurs when you pipe the Phazer. I run two bone stock 480's, including jetting, and have never had any midrange issues. Clean, sycronized carbs with proper jetting and properly adjusted idle circuit makes a huge difference with the transition from low to midrange with both my sleds.
    1977 Yamaha SRX (Mod Stock Drag)
    1979 Yamaha SRX
    1979 Skidoo Blizzard Cross Country
    1981 Yamaha SRX
    1981 Yamaha SS440
    1981 Kawasaki Invader LTD 4/6
    1981 John Deere Spitfire
    1982 Yamaha SRV
    1989 ET400TRN
    1991 Yamaha Phazer ST
    1992 Yamaha Venture TF

  3. #3


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    Sounds good. I ran the carbs through my ultrasonic cleaner and will be installing them today. I also installed new rubber plugs since the originals seemed to be a bit on the brittle side.

  4. #4


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    Got the carbs back in and it runs perfect. These old phazers are a hoot to ride. glad i bought one.

  5. #5
    Senior Member Stock
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    Nov 2011
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    Yellowknife, NWT
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    Great to hear. Keep them clean and you should not have any midrange problem. I still get great gas milage on mine even running with the newer high tech sleds.
    1977 Yamaha SRX (Mod Stock Drag)
    1979 Yamaha SRX
    1979 Skidoo Blizzard Cross Country
    1981 Yamaha SRX
    1981 Yamaha SS440
    1981 Kawasaki Invader LTD 4/6
    1981 John Deere Spitfire
    1982 Yamaha SRV
    1989 ET400TRN
    1991 Yamaha Phazer ST
    1992 Yamaha Venture TF

  6. #6


    Default

    Quote Originally Posted by NorthofSixty View Post
    If it is stock, clean carbs properly jetted, and has unmodified airbox in place there should not be a midrange lean spot. The lean midrange typically occurs when you pipe the Phazer. I run two bone stock 480's, including jetting, and have never had any midrange issues. Clean, sycronized carbs with proper jetting and properly adjusted idle circuit makes a huge difference with the transition from low to midrange with both my sleds.
    I've cleaned my carbs, replaced the rubber plugs, but still have a rich issue? How do you adjust the idle circuit? I believe the fuel screw closest to the cylinders is a fuel screw?? correct?The clutch cover says 1&1/2 turns out. I'm at 3/4 and i believe it's too fat now? Doesn't clean out until im on the main for a bit. if i went even farther out i believe it would get worse? Am i missing something ?? obviously I am. horrible mid range blubber. all stock.

  7. #7


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    You need to clean your carbs again. Running them through a ultra sonic cleaner would be best. The phazer carbs need to be meticulously cleaned.

  8. #8
    Senior Member Stock
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    If you still have the problem you can check a couple of things. I keep an eye on my choke cables as there is not much extra length to spare on a Phazer. They are prone to sticking and don't always seat properly. If either cable is even slightly lifted it will run horribly rich in mid range with lots of excess smoke. If your chokes are seating properly and there is good free play in the cables and you still have the problem I would check the size of the slow speed jet. It may have been changed to a larger size at one time.

    There are probably several methods people use to adjust the idle mixture. I focus on adjusting for maximum low end power just before clutch engagement as follows:

    With the engine "fully" warmed up I start with idle mixture screws at factory setting. I check and sync the carbs using a pair of vacuum gauges (cheap on eBay). Then I use the idle adjust screw to bring the idle up to a steady 2500 rpm. I turn each idle screw in or out 1/8 of a turn and wait a bit to see if the rpm's rise. Which ever direction results in an increase in rpm I continue to adjust both carbs 1/8 of a turn at a time until the rpm's peak. Use the idle adjust screw to bring the rpm back down to about 2500 each time so you do not reach engagement rpm. At some point the rpm's will start to drop when you make the next 1/8 turn. At that point I turn them back to the point where the engine rpm's peak. (If I do not see any change in rpm with the idle mixture screws at 2500 rpm I lower it to 2200 or even 2000. I try to use the highest rpm possible where adjusting the idle mixture screws has a noticeable affect but generally I do not exceed 2500 rpm to allow the adjustments to be made without reaching clutch engagement)

    To make the final adjustment I bring the idle back down to spec around 1500 rpm with the main idle adjustment screw. I lift the track off the ground and lock the brake on real hard. With the brake locked on I briefly snap the throttle wide open. If the engine spins the track and pulls right through mid-range towards full rpm with the brake locked on I am pretty much bang on. Usually I am slightly lean after the initial set up at 2500 rpm and have to turn the idle mixture screws out (rich) 1/8 to 1/4 turn to pull through the mid-range without hesitation.

    What ever method you use, if you do it on a day that is close to your average riding temperature it will cover a pretty wide range of temperature change before it needs to be readjusted on a stock set up.

    This works for me with the Phazers but I am sure others have methods that work equally as well.
    1977 Yamaha SRX (Mod Stock Drag)
    1979 Yamaha SRX
    1979 Skidoo Blizzard Cross Country
    1981 Yamaha SRX
    1981 Yamaha SS440
    1981 Kawasaki Invader LTD 4/6
    1981 John Deere Spitfire
    1982 Yamaha SRV
    1989 ET400TRN
    1991 Yamaha Phazer ST
    1992 Yamaha Venture TF

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