carb jets

This bike set since 94. Before I put any cash into this machine I wanted to hear it run. pulled the carbs and dismantled them.soaked them in cleaner for a couple days and ordered gaskets. it was a while before I had a chance to put them back together down loaded a parts list and diagram to do so.put them back on checked the air filter for mice nests and there was none and also found it to have a k&n filter in it. a new battery and a little fuse box problem (replaced) and I got it started. It runs so rich it blows black and will not attempt to idle.
The two jets under the diaphram could I have them backwards? my parts list says they are discontinued so I put the smaller to the front of the carbs.

 

YAMMYLOCKS AND THE THREE JETS​

- A Bedtime Story -​

Main & Pilot air jets use the same size threaded bore hole sizes up on top of the carb body, underneath the slide piston assembly. The main air jet is in the "center" hole and is the lower numbered (smaller opening) jet. The pilot air jet is in the hole closest to the "front" of the carbs, front meaning nearest the cylinder head, and is the higher numbered (larger opening) jet. The rearmost hole is for the cover plate hold-down screw, if so equipped (some model carbs did not use the cover plate nor the hold-down screw).

These positions correspond very nicely, and symmetrically, to the positions of the main and pilot fuel jets down below, in the bottom of the carb body (pilot forward, main in the center).

The passageways drilled into the carb body that the air or fuel takes through such said passages are tiny, and need to be cleaned THOROUGHLY. As in cleaner-than-operating-room-clean, and more like "compter-chip-assembly-facility" clean.

As well as every other orifice, opening, and passageway in the carb body and bowl. Otherwise, they just aren't really clean.........

 

You should have the 40 in the forward location (pilot jet) and the 110 in the rear location (main jet).

 

Robert, actually I think he's talking about the AIR jets up on the top side of the carb. A XJ650H should use a pilot AIR jet of #195, in the "forward" position, and a #50 main FUEL jet in the center position.

TEBO: I think you have your air jets reversed...........

 

Gee, you think the word "diaphragm" would have tipped me off. I'm sorry, I'm in class and not paying total attention.

 

Not paying total attention to this forum, or to your class?

Or both?

 

One word, yes.

 

Thank you all, I thought that was my problem

 

Have you visited yamaha-motor.com and looked up the parts diagram? I'm looking at your exploded view right now and it shows the correct location for each jet for the whole carb.

 

Although these are off a 750 and are different Sized ... You get the idea.

The Main AIR Jet is an AIR Jet.
A Main FUEL Jet would have a larger hole than a Pilot FUEL Jet ...

But, these are AIR Jets.
The Big Metering Port is Pilot Air
The Small Metering Port is Main Air