'78 Kz1000, had to drill out stuck pilot air screw

8x 1.5mm would be a Coarse thread. More like 8x 1.0mm or 8x .9mm would be a fine thread.
Got any pictures of how big the piece that is left looks like? I got one out by heating the body around the screw hole carefully with a small butane torch and soaking with PB Blaster. Took a while but it cam out. First drilling with a small drill, tried the left handed but it didn't do it. Then carefully using my smallest extractor. Pain In The A** for sure.

Motor Head wrote: 8x 1.5mm would be a Coarse thread. More like 8x 1.0mm or 8x .9mm would be a fine thread.
Got any pictures of how big the piece that is left looks like? I got one out by heating the body around the screw hole carefully with a small butane torch and soaking with PB Blaster. Took a while but it cam out. First drilling with a small drill, tried the left handed but it didn't do it. Then carefully using my smallest extractor. Pain In The A** for sure.

Good deal, I haven't ordered yet, I will order the 8mm x 1.0 then. The only one at the hardware store is 8mm x 1.25.


I have run through the easy-outs and drilling -- tried a small hole drilled and small easy out, nothing. Drilled a bigger hole, bigger easy out, nope. I'm out of brass now almost, there's enough material to drill then tap it.

It's all an experiment now, because the chance that the pilot air screw's function will be correct now is 'up in the air' so to speak -- I would need better tools and a bench press to correctly re-drill the pilot air screw hole and get it to match the factory hole there. But I'm anxious to try it.

My plan for this bike is to get it running first, get it road-worthy, then tear it down and repaint/etc. all the cosmetic stuff, and I'll probably have to swap in a new carb #2 carb body at that time, not sure yet.





My first task is to get it to start after sitting on the seller's back porch, close to the ocean, since 1984, 29 years of sitting. Big job here.

Could try various size taps in a good pilot hole in one of the other carbs.

Of course, be gentle. The correct size tap will easily and readily screw into the hole, just like the pilot screw does.

A metric thread gauge is a handy inexpensive tool.





Good Fortune!

Motor Head wrote: 8x 1.5mm would be a Coarse thread. More like 8x 1.0mm or 8x .9mm would be a fine thread.
Got any pictures of how big the piece that is left looks like? I got one out by heating the body around the screw hole carefully with a small butane torch and soaking with PB Blaster. Took a while but it cam out. First drilling with a small drill, tried the left handed but it didn't do it. Then carefully using my smallest extractor. Pain In The A** for sure.

Well I figured it was the finer of 2 options I had offered anyway! :woohoo:
Is it possible for the average shmo to even buy a tap that fine?
I can take an empty carb bodie to my tool/die guy tomorrow and ask him what the thread is and where to get one

If you can get one of the others out, then use a thread pitch gauge to find out what it is. Or maybe someone here can do that for you. Better to find out the size, then order the Tap. Ace Hardware has a good selection of Metric screws, taps and dies, etc. If you can get one out, they should be able to set you up with a Tap.

Did you spray in through the Air Horn/ Air Jet with penetrate? So the tip of the screw is soaked?

Motor Head wrote: If you can get one of the others out, then use a thread pitch gauge to find out what it is. Or maybe someone here can do that for you. Better to find out the size, then order the Tap. Ace Hardware has a good selection of Metric screws, taps and dies, etc. If you can get one out, they should be able to set you up with a Tap.

Did you spray in through the Air Horn/ Air Jet with penetrate? So the tip of the screw is soaked?

wireman thanks for your offer of help, patton I had never seen a thread pitch gauge I'll go buy one at Ace tomorrow:


Lordy I'm there man
driving to the big Ace Hardware near me, they have them online maybe in the store too
www.acehardware.com/product/index.jsp?pr...8450.2628076.2629205

That will without a doubt tell me which tap to buy, I'll bring a good pilot air screw with me tomorrow, measure it on the spot then buy the right tap.
+
MH I did spray into the pilot jet hole and the pilot air intake hole to soak the tip side of the stuck pilot air screw to no avail. It's probably a combination of the salty air, 29 years of sitting, and the oring around the inside of the pilot air screw creating friction

Okay I got real lucky, went to my tools, a metric tap/die set I had, what's left of it, had one of those thread gauge tools, the pilot screw threads are --

0.75


Sheesh. So here's my question, I took my caliper and read 6.92mm in approximate diameter of the pilot air jet's threads -- do I thus have

7mm x 0.75 pilot jet?

My tape measure doesn't have that small of lines on it! :woohoo:

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