Anyone have experience with carb update jetting for Phazers?

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Brettm57

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Sep 28, 2003
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I just found that in '96 Yamaha offered a jetting kit to cure the midrange lean condition on the Phazers. It doesn't seem to be well known, at least not in this area. A buddy of mine that used to work for a Yamaha dealer told me about it. Does anyone here have any experience with this kit, what does it consist of, and did it cure the problem? I've got an '88 Phazer (yeah I know, I should trade up!) with an Aaen pipe that I burnt up three sets of pistons last winter due to a midrange leanout that I can't get rid of. I'm hoping this kit will cure my problem, pistons are expensive! Not to mention the inconvenience of having my sled quit in the middle of nowhere.
 
Yes there is a old service bulletin from around 1996 I believe. Basiclly you can change the primary and main nozzles for a richer mixture. The primary nozzle part #80L-14489-00-00 has two .9mm holes as opposed to the stock nozzle's one 1.0mm hole.
There are at least 3 different main nozzles

Part #8Y2-14941-3A-00 is STD. has an OD of 6.5mm, ID of2.2mm and 12 0.7mm air bleed holes.

Part # 8Y2-14941-1A-00 has an OD of 5.5mm, ID of 2.2mm and 10 0.7mm air bleed holes.

Part # 8Y2-14941-2A-00 has an OD of 5.5mm, ID of 2.4mm and 10 0.8mm air bleed holes.

A smaller OD will richen the mixture at snap throttle and lean it at mid to WOT during steady throttle.
A larger ID will richen the mixture at mid to WOT condintions
Fewer and larger air bleed holes will richen the mixture at mid to WOT conditions.

You can use any combination of the listed nozzles for a wide range of mixtures, depending if you want to richen the mixture during snap or steady throttle condintions.

Full rich, at steady mid to WOT would be using the 80L primary and 2A main nozzle. Leanest would be STD primary and the 1A main nozzles.

For quick snap throttle conditions, richest would be 80L primary and 2A main nozzles. leanest would be STD primary and STD 3A main nozzles.

There is a chart that lists the calibration options from lean to rich in the service bulletin. Also the hole in the STD primary nozzle must face towards the air box.
 
Yamaha came out with the different nozzles starting with the 1995 Phazer model year.

Most people just change the primary nozzle to enrichen the midrange. I have seen a few people try the 8Y2 14941-2A-00 main nozzle, but it didn't help and caused a bog off idle, I think it was a little too rich for the mid elevations around here 3000-6000 ft.

With pipes the primary nozzle is the fix everyone around here has done to fix the lean midrange.
 
What jets do you have in that thing ? I ran a Aaen pipe on a 85, 86,87 Phazers with 147.5 jets for years. Wide open across 10 mile lakes, roads and trails and never a problem. :?: Nothing like the light weight of a Phazer to throw around. Loved those sleds. There are different causes to piston failure than just lean. Where are you currently on the carbs ? 8)
 
Jetting

Right now I've got 150 mains in my sled. But I also installed a set of Wiseco pistons with the boost ports in them. Apparently they draw enough more air that I need to richen it up more yet. The engine really breaks up at 1/2-3/4 throttle.... but wide open, does that thing ever go!
 
Sounds like you definetly need to do some mid-range tuning. Start with checking your carbs to see if it still has the standard nozzles. You can jet that thing very fat, and still have a part throttle burn down. If your cruising along at half throttle, the main jets do not even come into play untill aprox. 3/4 or more.

Mr. Sled, I sent out the copies today.
 
I just put a new Aaen pipe on my 85 Phazer today. I put 148 mains in it to start with. I ran it for a few min. on the stand and it sounded good but we don't have any snow to test it yet here in SW lower MI. After reading all this I am getting worried about this lean midrange condition that I hear can effect Phazers. What primary and main jets do you think I should start with so I don't burn this old girl down? If you would give the part number of the primary jet because I don't want to make a mistake. I would be greatful for the advice. The Phazer is all stock otherwise.

Thanks!
 
Change the primary nozzle to part no. 80L 14489-00-00. This nozzle has a thru hole which allows the nozzle to draw more fuel in the midrange operation of the carb. A different main nozzle part no. 8Y2 14941-2A-00 may also be put in but I found it to cause a bog off idle as Kgmz stated but the elevation we ride at is from 4000 to 6500 feet. It's purpose is to enrichen the carb just off idle somewhat. I think this mod is not required for the normal 485 cc stock engine especially at higher elevations although you may need it for lower elevations. I would leave the main nozzle at the standard which is 8Y2-14941-3A-00 for now to see how it performs. I doubt it would cause any harm to the engine as it is just to provide more fuel off idle when the throttle is snapped open. As far as main jets go up two jet sizes from the stock setting for your altitude as a starting point and then jet down as required.
 
Bad news......Using 148 mains and the 80L 14489-00-00 primary nozzle she burned a piston down after six miles. :( I checked the plugs twice in those six miles too. They looked paper bag brown both times. But when it quit the plug looked pretty white with specs of aluminum on it. I ordered my parts to the tune of $150. What would you guys try next? The 8Y2 14941-2A-00 main nozzle? 150 main jets? Larger pilot jets? Or all te above?

By the way. I was only goin about 10mph when it burned down
 
If she burned down at lower speeds, I would try the 80L primary and 2A main, and go up a couple of sizes on the pilots also. Its best to start out to rich and blubbery, then work your way leaner if required.
You may also want to check the pilots for dirt and varnish, sometimes those low speed curcuits with their small passages will plug easily.
 
I called Aaen and talked to a mechanic. He told me to go up 2 sizes on the pilot jet. He said to try a 100 or 105 up from the stock 95. These are hard to find but I ordered a 105 because I figured out that it is stock on an old Exiter. He also said to use both the 80L 14489-00-00 primary nozzle which I already have and the 8Y2 14941-2A-00 main nozzle along with the larger pilot jet. Has anyone on here tried a lager pilot before?
 
Another Idea

I posted on the other board, but I've got an '88 Phazer that I just bored .020" with the matched set of Wiseco pistons, polished ports, milled the heads .020", and a DG pipe. I've also got an '87 Phazer my son rides we did the same thing to. We started both sleds out with 150 main jets, and stock metering tubes. After our first test run a couple days ago, the boy's sled had just a little leanout noise (ping) when you first crack open the throttle, and my sled knocked intermittently no matter where the throttle was. After thinking about why my sled knocks so much worse than the boy's, I decided that maybe the spark timing was too advanced. So I pulled the engine and retarded the stator plate 2 degrees. Now my sled runs just like the boy's. I'm going to experiment with the meter tubes next, which I think will cure the low end problem.

Anyhow, long story short, you might want to play with your ignition timing. There's a way to check it with a timing light according to the manual.
 
And....

....I can verify what Mtnviper about cleaning the carbs, and have the melted pistons to prove it! My problem was belt dust had plugged some of those little tiny holes in the meter tubes of one of the carbs. Now I run a toothpick into each one of those holes as part of my carb cleaning routine.
 
Thanks for all the input! I have the 2A main nozzle ordered and also a set of 105 pilots. I will clean the carbs completely again. I usualy run a wire thru all holes in all jets and nozzles. I am also going to switch from 148 mains to 150.
 
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