Pilot Fuel Screw Success!

[Jon78gs1000]

I won the battle with the fuel pilot screws!
Made 4 blanks and just got the die I ordered,and today I put threads on them and cut screwdriver slots in the little darlings.
Tried them in the carbs and Success! :-D
I just finished dipping the carbs,a complete disassembly and new o-rings.
Next is to set the valves,intake boot o-rings then start her up.
I put a 12* taper on the screws but I think an 8* is closer to factory.
Next set will be 8*. A 12* taper will cause less turns to reach proper fuel
passage.
The die made the threads just tight enough to allow me to not need any springs,which is good because there wern't any on the screws when I first took them appart. So it's a bonus. I'll tighten the die a little for the next set and try to find springs.
I'm having a GOOD day.
\\/ :-D

[BadBillyB]

Now that you are finished with those, how about making some 0-2 needle jets for a GS1000.....Mine are worn out and I suspect most all of them out there are too, to some degree. They are causing rich mixture problems below 3K RPM's and are no longer available except direct from Mikuni @ almost $80 for a set of 4 shipped....After a long decel, there is so much fuel drawn in that I get a hesitation when I re-apply the throttle.......My carbs are perfect except for the needle jets....Mikuni #258 series 0-2 ....These should be easy for you to make. I can provide you with the correct hole size for them if your interested........BadBillyB

[Jon78gs1000]

I think its too narow a taper to do it on a lathe. When the tool cuts the brass the force of pushing into the metal to cut it tries to bend the brass.
But hey i'm game if you are :-D
I need as much dimensions as I can get. My jet needle is a 5dl36-5.
I need a really accurate taper angle or pitch.
The total Length.
The diameter of the straight part that goes into the slide.
The length of straight part from the end where clip groves are to where the taper starts.
The lenght from where the taper starts to the point
# of clip groves.
distance from the end to each grove.

Wow its a lot of dimensions. I can't find a place to get brass, but I'll find some somewhere.

[BadBillyB]

Jon, I really appreciate your enthusiasm. Your thinking of the jet needle...What a bugger that would be to make. Its like a tooth pick. What I am talking about is the "needle jet"....There are 2 pieces above the main jet. The breather pipe is what the main jet screws into. Just above the breather pipe is the needle jet. It is what controls the fuel flow around the taper of the needle when you open and close the throttle up until the main jet takes over. It is only about a 1/2" long and is quite small. It looks kind of like a main jet w/o the threads, and about the same size.....The needle is anodized, the needle jet is not. The jet, being softer, tends to get oval over time from the needle rubbing against it. Mine look like they have suffered from corrosion and are pitted looking.......The difference in sizes are in increments of .001" so the tolerance is pretty tight.....I would be willing to bet that fixing my needle jet problem will increase my fuel mileage at least 5mpg......BadBillyB

[Rock]

Sudco has most parts for Mikunis in stock and will ship them. Also you can find dimensions for the needles. http://www.sudco.com/cat32/52-54.pdf and http://www.sudco.com/

[Jon78gs1000]

Jon, I really appreciate your enthusiasm. Your thinking of the jet needle...What a bugger that would be to make. Its like a tooth pick. What I am talking about is the "needle jet"....There are 2 pieces above the main jet. The breather pipe is what the main jet screws into. Just above the breather pipe is the needle jet. It is what controls the fuel flow around the taper of the needle when you open and close the throttle up until the main jet takes over. It is only about a 1/2" long and is quite small. It looks kind of like a main jet w/o the threads, and about the same size.....The needle is anodized, the needle jet is not. The jet, being softer, tends to get oval over time from the needle rubbing against it. Mine look like they have suffered from corrosion and are pitted looking.......The difference in sizes are in increments of .001" so the tolerance is pretty tight.....I would be willing to bet that fixing my needle jet problem will increase my fuel mileage at least 5mpg......BadBillyB

A bugger it would be to do the needle.:-D
I don't think I can do any kind of accurate job with internal sizes. I don't know where you would get the right drill for the job. Sorry
What if you could find a bit that can drill it out a bit bigger,and drop the needle a notch or 2.It already has a hole so it would line up.

[lennymu]

My pilot screw angle

I put a 12* taper on the screws but I think an 8* is closer to factory.
Next set will be 8*. A 12* taper will cause less turns to reach proper fuel
passage.

I had one good pilot screw out of four. I put mne up on an optical comparator and made all of my measurements. My angle was precisely 6.5 degrees. Made my screws and installed them, and all is well.