Main Nozzels for viper carbs...

MURDER YAMAHA

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OK, so the main nozzels we all know are mostly unavaible anymore.
They are the piece the needle rides in. They are brass, and wear out with miles.
I have over 6500 miles on my Viper carbs and want to replace them.
I have plugged the Yamaha part number 89A-14141-48 into many searches.
I sometimes see a Mikuni P-8 number come up.
Anyone think these are interchangeable?

 

So, further research shows many different "Series" that these could be, such as 159 series, and others.
It appears they list different measurements for the nozzles to help determine which "series" you have.
Will have to measure some and see if I can figure it out. Hopefully one of these series of nozzels will work for us.
Here is the page I have been looking at.
 
I've never heard of anyone wearing out the nozzle. Not saying its not happening. Just never thought about it. Is it wear you can see? I run one step up in size with the 780.
 
I have seen twins with this problem. When my XTC was a 600 twin, it had around 2000 miles on it, and ran great. I had it in getting worked on at the local dealer, and they dropped my carbs, and busted a float stand off. He gave me an identicle set of carbs that he had laying around, and swaped all my jets over, except the nozzles. Ran horrible after that. Always suspected that they may have been a high mileage set of carbs. This Viper is the first sled I have had with this many miles on it, as most of my stuff has a max of 3,000, with most around 2,000.
 
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The one with the small holes is Viper.
Other is carbs 2 &3 on a 700SX
So, if you look at the web page I linked above, looks like the 499 series is interchangeable with the 640 series, and they have the 640 P8 available for the Viper. I don't see the 798 series though for the SX.
 

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Pic on the left is a nozzle with 5000 miles with the factory aluminum needle. Pic on right is a new one. You can see the wear at the top of the opening.
 

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I've never heard of anyone wearing out the nozzle. Not saying its not happening. Just never thought about it. Is it wear you can see? I run one step up in size with the 780.
There are other threads about this, one where I posted a picture comparing new to old.
Not to pat myself on the back, but this was a problem that it took me a while to figure out, and have shared this now with others on this site.
 
Pic on the left is a nozzle with 5000 miles with the factory aluminum needle. Pic on right is a new one. You can see the wear at the top of the opening.
I may have a brand new set that I would sell. Do you have yours out? What are the numbers on yours?
series 499, size P-8?
 
Yes, the Viper ones are 499 P-8
The SX ones are 798 Q-4 & Q-8

Visually, rthe 499 and the 798 are the same, except the Viper(499) has the tiny vertical holes.
From what I have read, the holes are just to better atomize the fuel.
They say the 640 series, which are available in all the sizes, are interchangeable with the 499 series.
And to me, it looks like the 499 an 798 should be the same as well.
So really, we should be able to use the 640 series for all Yamaha Triples?
 
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Yes, the Viper ones are 499 P-8
The SX ones are 798 Q-4 & Q-8

Visually, rthe 499 and the 798 are the same, except the Viper(499) has the tiny vertical holes.
From what I have read, the holes are just to better atomize the fuel.
They say the 640 series, which are available in all the sizes, are interchangeable with the 499 series.
And to me, it looks like the 499 an 798 should be the same as well.
So really, we should be able to use the 640 series for all Yamaha Triples?
I don't know for sure as I've never tried those.
 
Well, Im about to. We will see what they look like when they show up.
More curious than anything. This would be a good resource for folks that need new ones, that Yamaha no longer makes.
 
Thanks for sharing. I have over ten thousand miles on my Nozzles. Im gunna pay attention and look for wear next time its apart. Nice update with pictures.
 
Nozzles wearing out is a real thing. At least on the twins for sure. I replaced nozzels on out XTC 500 with about 11,000 miles on it, Been in the family since New, last year. It became an entirely different sled.
 


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