Does the emulsifier tube wear?
Posted February 15, 2007 - 12:36 PM
When I went into the local Yamaha dealer to ask about replacement costs (i've since decided to go with the JD kit after reading posts here) the mech also informed me I would probably need to get a new emulsifier tube.
Is this just a grab for more money or should both the needle and emulsifier tube be replaced at the same time? Does the emulsifier tube (which I must admit to having no idea about) wear as well? Bike's an 02 WR 426.
Posted February 15, 2007 - 01:45 PM
Posted February 15, 2007 - 01:57 PM
Posted February 15, 2007 - 02:05 PM
You may want to search Needle Jet there may have been some discussion on how needle jet affects mixture.
You may also want to search the YZ forum since there has been a lot of talk on the ZIPTY carburetor mods latley (some of which may not apply to your carburetor.
Posted February 15, 2007 - 06:24 PM
I have to admit I have no idea what an emulsifier tube is? What part number is that on the schematic?...SC
It's the first i've ever heard of it as well, which is what's got me stumped. Can't find reference to it in the manual.
Assuming the mech means needle jet, would that be included in a JD jetting kit?
Posted February 15, 2007 - 07:52 PM
Posted February 15, 2007 - 09:03 PM
Symtoms of a worn needle jet are an overall rich mixture, and plug fouling if they're getting really bad.
Hell back in the 80's the 920 and i believe the 750 Virago ran hitachi carbs. When these needle jets wear out you can't get factory replacements and I'm not aware of any from thee aftermarket.
Posted February 15, 2007 - 10:00 PM
I contacted the local dealer who said, based on plug colour and my mid-range problem, that it sounded like a worn needle. He suggested I lean out the needle, so i moved the clip up one position.
It fixed the problem in terms of how the motor sounded and behaved, but the plug still looked a bit rich.
Just last week the bike started running rough again - same thing - moved the clip position and its fixed it, but it's only a band-aid fix. Going to properly fix it now with a new needle.
Posted February 15, 2007 - 10:05 PM
I don't want it happening again in a year's time.
Thing is, I've had the bike since late 02. It did 7000kms before this problem and now it's rapidly deteriorated over the past twelve months.
Posted February 15, 2007 - 11:00 PM
Posted February 16, 2007 - 07:20 AM
Posted February 16, 2007 - 08:31 PM
I'm experiencing the same problem where no matter how lean I went with the carb settings, it was still WAY fat. I've just changed out the tube to see if it fixes the problem, but I haven't ridden the bike yet.
One thing that I believe is the cause is a loose clip. I was using a clip that was extremely loose. I began having the jetting issues when I switched to the new clip. I believe the old clip allowed the needle to move within the jet and wear the jet. But that's just my theory and I have yet to prove that I've solved my jetting issue.
Posted February 16, 2007 - 08:37 PM
The needle jet is what would be called the emulsion tube in an automotive carburetor. It helps the fuel coming up the main jet mix with air to create a fuel mist and atomize as it enters the intake of the cyl. head. How did the jet needle get worn? Was the lock nut above the needle loose? If it was I would guess you need to replace the needle jet as well. First time I've heard of this problem , I must admit. Good luck getting a neelde jet from the dealer. !! WR Dave.
I was able to order a needle jet from my dealer without issue. Part # on an '03 WR450 is 5JG-14947-00-00. My parts manual calls it Nozzle, Main.
Another symptom of mine was very poor gas mileage.
Posted February 24, 2007 - 12:10 PM
I discovered it was running waaaay too rich. I bought it second hand and have been happy with how it's been running (for the past four years) but haven't really messed with the jetting. I wish i had of now, heaps more responsive.
It was running a 180 main jet which, combined with worn needle was why it was running so rich.
Thanks for the advice guys.