Very tight JIS screws

I could not get the timing plate adjustment screws loose on my kz400. Not even with my Vessel and Craftsman inpact tools. Just boogered up the heads more.
Back in January, I bought a pair of Vampliers that I never used. They got all 3 adjustment screws out. Great tool.
www.amazon.com/gp/product/B08P64T6NQ/ref...05_s00?ie=UTF8&psc=1

I've heard of them before, but never found anyone who had used them.  Now I'm gonna get me a pair.  

Scotty

I have a 1/2 inch impact gun but for small screws such as what’s on float bowls I use my Milwaukee impact screw gun. The trick is making a standard 1/4 inch hex #2 bit act like a JIS bit. I do this by filing down the end of the brand new #2 bit so that it doesn’t cam out. And it works as long as I hold the bit firmly and square to the work. 

Unless you need the hex driver, there's no reason to buy special jis bits.  They come in practically every Japanese bike tool kit.
Second, internal engine screws most likely have locktite, so use some heat.  The countersunk bearing retainers can be a pain.
Any stubborn screw that you get a hold of, I use a set of battery pliers (see link) that I ground the tips to more of a point.  They grab 10x better than vice grips and the fastener is usually junk after.

STEELMAN 77020 Battery Terminal Pliers a.co/d/dEbGJpq

ckahleer wrote:

I could not get the timing plate adjustment screws loose on my kz400. Not even with my Vessel and Craftsman inpact tools. Just boogered up the heads more.
Back in January, I bought a pair of Vampliers that I never used. They got all 3 adjustment screws out. Great tool.
www.amazon.com/gp/product/B08P64T6NQ/ref...05_s00?ie=UTF8&psc=1

 

We're hopeless tool junkies. 

EDIT: (Well, slmjim is anyway... )

We have a set of three VamPlires. They are some of the highest quality tools we've ever seen.  They are available individually, and also come in a set of three, different sizes & slightly different jaw designs.  If you appreciate very-high-quality tools, you won't be disappointed with any VamPlire tool.

Good Ridin'
slmjim & Z1BEBE

I got them out in the end. I tried the JIS bits on an impact driver, but the screws were so tight the heads just got chewed.
I cut a big, deep slit in them with an angle grinder, then gave them a few more whacks with the impact driver with the biggest flat-head bit. They came out easily. Piece of cake!

Adapt and overcome.   

Scotty