Originally Posted by porterdog
OK, here's a tough (I think) app for you...
What should I use to hold the needle-jet holder in the stock carb on my XR650R?
The needle jet holder screws into the carb body (obviously, theres plenty gasoline about) and then the main jet screw into the bottom of that. IF I could lock my needle jet holder down I could change my main jet simply by taking the big cap off the bottom of the carb. What USUALLY happens is that when I try and extract the main jet the NJ holder also spins free, and by virtue of the fact that there's an... anti-slosh cup? trapped between, the entire assembly will NOT come out the bottom so I have to take the bowl off....
You'll likely need to remove the needle jet holder in the future, plus, these are small parts with relatively fine threads, so using a red threadlocker would be prudent at this here juncture.
Then, you'll be fiddling with the main jet-installing and uninstalling periodically which as you install and tighten that main jet you very well may exceed the breakloose torque of a low strength 222 threadlocker if it were applied to the threads of the needle jet holder. So, I think 222 is out as well.
Get out your trusty old blue threadlocker, start off with clean dry threads, apply some blue to the bottom 3 or 4 threads (one free falling drop would be too much, so be careful) to the needle jet holder. Spread the threadlocker around the needlejet holder and make sure to get the material in the 3 to 4 threads all the way in the thread roots, then gently blot with a paper towel. don't blot off all of the blue, just blot to the point you can see roughly half of the thread depth. We blot because we don't want any squeezeout to go where it shouldn't. Install to the proper depth and let sit overnight.
Now you'll be able to swap mains and not have to worry about spinning the needle jet holder.
This very application is similar to installing studs. You use a high strength threadlocker (with a higher breakloose and prevailing torque) to hold the stud in place, then you use a medium strength threadlocker (lower breakloose and prevailing) on the nut. This way, upon removal, the nut can be removed from the stud without the stud turning in it's hole.
Don't forget carbs are chocker block full of tiny passeges, so don't go banana's with the amount of threadlocker.
Don't drive like my brother.