Pilot Jet Adjustment Screw

[WAC1972]

Hello, I went to adjust my pilot jet screws and found that the previous owner has one of them stripped very badly. I can turn it in but not out. Can these screws be replaced and if so does anyone have a suggestion on how to get it out. It is a standard head screw and the head is in bad shape. Thanks

1998 Royal Star...

[Flyinfool]

Find a screwdriver that has the exact right size blade and make sure that it has nice sharp edges on the tip. Regrind it if necessary to be sure it is sharp. Use a lot of pressure to prevent it from slipping and further damaging the slot. Make sure that you are perfectly square and lined up. If this does not work then it will get uglier fast.

[Marcarl]

Worst comes to worst.

Find a drill bit that is the exact size for the hole, carefully drill off the top of the brass screw being careful not to go too deep. This should leave you a centering spot to use a smaller drill to drill out the brass screw, again careful not to go too deep and make sure you get it lined up square,, good and square. Once that is done use an easy-out to remove. Use lots of air blowing to keep things clean where you can see what kind of 'mess' you are making. Slow and easy is the by-word.

[Flyinfool]

Worst comes to worst.

Find a drill bit that is the exact size for the hole, carefully drill off the top of the brass screw being careful not to go too deep. This should leave you a centering spot to use a smaller drill to drill out the brass screw, again careful not to go too deep and make sure you get it lined up square,, good and square. Once that is done use an easy-out to remove. Use lots of air blowing to keep things clean where you can see what kind of 'mess' you are making. Slow and easy is the by-word.

 

If you are going to drill as Marcarl suggested, get some left hand drill bits. The left hand bits if they catch while drilling will spin the screw out. A standard right hand drill bit, if it catches will ram the needle hard into the seat.

[Neil86]

Not sure if you have the carbs out on the bench now...or on the bike still....can you get some

penetrant like PB blaster into the "well" the screw is in to allow it to flow down the threads?

[WAC1972]

I got it out! Some penetrating oil and an easy out extractor and it came out easily. Now where do I get replacements. Not even sure what the carbs are. I am sure they are original. Where would I find markings on them? Would these adjusting screws come in a jet kit or can I purchase them separately? Thanks in advance for any info.

[Prairiehammer]

The pilot screws can be purchased separately. Part Number 4NK-14923-00-00

http://www.boats.net/parts/detail/yamaha/Y-4NK-14923-00-00.html

[WAC1972]

Thanks I ordered 4 today from Boats.

[WAC1972]

I have been having issues with getting the settings right on the adjusting screws. I put in 4 new screws and I set them with the tach idle method and it ran so-so. I then reset them using my Carbtune doing each one separately and then the whole sync. Once again it ran okay but not great. I have been tweaking it here and there but just haven't found the sweet spots. Just two days ago I reset all the screws with the Carbtune and the bike ran great on my way to work. (bike was warm when setting screws) When I came out 10 hours later pulled the choke out the bike started poorly and wasn't firing on my back left cylinder. After letting it warm up I pushed the choke in and the back left cylinder started to fire and the bike smoothed out. I have a 20 mile ride home and the bike has never run better. Yesterday I re tweaked the back left and once again I had the exact same scenario when I left work. Any ideas why I would be having this issue of the cylinder not firing with choke out but running really well when warmed up? I pulled the plug and it looks good. Thanks

[tz89]

Do you mean it idles really well once warmed up, or it runs at speed really well when warmed up? From what you say it sounds like you need to turn the screws in a bit, but I'm not convinced this is only an idle jet adjustment issue.

 

btw - it would help if you could tell us how many turns out each screw is set. Gently turn in each until it seats counting the turns.

[WAC1972]

It runs really well through all rpms when it is warmed up. I'll count turns when I do another adjustment. It just seems strange because until the other day it ran okay but not great thru all rpms but started perfectly with choke. Now it runs great but that one cylinder won't fire with choke.