85 xj700 (non x) primary jet needle halp

Hello! My name is Allen, forgive me if there is already a thread covering this.. This is my first ever forum.

the problem I face is primary jet needle inconsistency.

I have done a lot of reading, on this forum, about identifying my carb type and everything associated with it.


Bike is an 1985 Yamaha xj700 maxim
vin says 1fg00/
Hitachi carbs : HSC33
jet needle :y-20

The problem I found while rebuilding the carbs is that on of the needles. Is not long enough to plug the primary jet. As a matter of fact compared, to the rest of the jets all marked “y-20” it’s shorter. that poses a problem with it sucking fuel below 20% throttle when it’s not in use. Ie causing me to either flood or run extremely rich on that cylinder.

I have ordered an entire rebuild kit and all the needles with the same length as the short one so I didn’t use them.

So instead I ordered a used oem y-20 needle from eBay to replace it and it is identical to the short needle.

mind you.. they are all stamped y-20

I’m really scratching my head and I don’t really know what to do..
Is this a common occurrence?
How should I proceed?
Any help really is greatly appreciated!




I this photo both the short needle and the long needle are installed ^^
close up of the short needle installed
And finally a comparison of the king needle and short needle both stamped y-20
I’ll be returning the short needle due to a damaged tip as it’s the one I ordered from eBay

 

I would like to add that to my knowledge all of the oem jets marked y-20 on eBay or elsewhere are all short like the needle shown on the left of on of the photos. Also that brass insert had fallen down in the pictures but I’m pressing the valve all the way in with my finger representing idled Am I going crazy for thinking that they should be longer? Did they make longer y-20 needles?

 

Crazy little bend on the point of the left needle.

 

I’m aware, that’s the needle I ordered from eBay. I’m returning it today. But it’s exactly like the needle I have that’s short. Minus the bent tip lol

 

Update I pulled a needle out of my xv-1100 donor that has hitachi carbs. Needed in it is stamped y-33. And is identical to the one out of my xj700 stamped y-20

 

2 different needles y-20 and y-33
it is all about the tapers of the needle . the length may be the same but the taper is different

 

A stock Y-20 needle should be about 48.20mm overall (total) length.

 

Update I pulled a needle out of my xv-1100 donor that has hitachi carbs. Needed in it is stamped y-33. And is identical to the one out of my xj700 stamped y-20

why would there be two different size needles stamped “y-20”

 

I checked the difference between the two with a micrometer and they’re nearly the same. However that’s the only tool I have available to me to measure the diameters. I figured with the difference in tapers I could tune out the fuel changes vs the needle not touching the jet whatsoever.

 

1. That short needle doesn’t look good.
2. Needles can look the same, but the ramps and tapers and usually different…….