There are a few economical options out there to get the job done.
What you are looking for is something with "Single D" in the title.
is a socket that works.
Here is a hand tool that also works.
You can make a version of the 2nd link by taking a used .22 bullet casing and flattening one side of it. Others have claimed it works great. I tried it just for fun and it was jut OK IMO.
I am mentioning this one very cautiously. One other thing you can do that I personally did when I was trying to get the job done with the tools on hand was to take a thin, very fine tooth hacksaw blade and CAREFULLY saw a slot into the head of your needle. You then have something with which you can use an offset straight-slot screwdriver.
Attempt it at your own risk though because if you screw it up, you are really messing things up. It does work function very well though.

At the end of the day, the job is simple, but it is not easy due to the confined, very hot space.

I do go back to my original question, when you synced your carbs, what method did you use?

 

Yeah I have the first bit that you linked . I like the idea about the hacksaw blade. If I had just a tiny bit more room I'd be okay lol I have a carb sync tool.

 

Cycle Gear has Keihin FCR carb air/fuel mixture screws that have *****. Previously I literally took the carburetors off repeatedly until the gauge read the correct rpm. The included spring doesn’t fit require the oem pilot screw spring not the spring included and the washers and o-rings fit.

 

Oh yeah I've looked at those but couldn't find one that fit . I'll look at this brand see what happens ,that would for sure. Make life easier trying to dial the carbs in correctly. I have pilot screws between 1.75 and 2 turns out and it seems to enjoy it . But you can hear it jumping a little bit and I want it spot on haha

 

i
Used a digital tachometer gauge from Amazon and was able to dial in all of the pilot screws this way.

 

I have an older analog Actron dwell and tach meter but the point is still the same. The bike tach is not accurate enough for this work.

 

alright! See I was thinking that bike tach isn't gonna show 50 rpm drop like manual says so I was puzzled, when it said to hook up a tach. Where exactly does the fighting even go into , to show rpm on a cylinder?is it the little intake vents that you'd use to sync the carbs. ? I appreciate the info though! I'll for sure get that tach and those dang pilot screw and I'll be able to get this thing. Going the way it's supposed to be . I gotta say through currently this thing is running pretty dang good at what it's at. But idle is the only thing I don't like about it, all that jumping around bothers me . Thank you !

 

You’ll need to remove the front fairing. The tach will connect to two screws on the back of the instrument cluster.
its a really easy process, removing the fairing is the worst part.