A simple solution to the #98 problem

[Old Fogey]

In Randakk's Technical Tips for the GL1000, he recommends changing the idle air jets (the ones in the brass elbows) to a #98. But.....the problem with that is the Kei-Hin 99164-611-0980 have not be available for a long time.
His solution to that is to solder up the original jet and redrill the hole. That is none too easy, especially for owners who are not handy with tools.

I have found a simple solution, using 99101-393-098 jets. These seem to be reasonably available.
They do NOT screw into the elbows. However, the button head on them is 6mm diameter, which is about the same as the bore of the air pipes.
So there are two easy options, in as much as it doesn't matter which way they are inserted into the bottom of the air pipes, as the rubber holds them firmly in position one it's installed over the elbow spigot.
Alternatively, you can set them up and drill the elbow with a 4.5mm drill and tap the resulting hole to M5. This allows your to screw the jets into place.

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[Track T 2411]

Nice tip! I've avoided doing the soldering thing for my 76, just because it seems kinda fiddly. This looks much simpler...

[redglbx]

Great tip Fogey, personally I don’t recommend drilling jets as it’s a very sketchy process that isn’t very good with variable flows and sizes. Many years ago Holley carbs came out with a paper warning against drilling jets because of the variability with the results. They flow their jets to determine sizing not drill size,, not sure if Keihin follows the same process or not. But I do know that flow is determined not only by the hole diameter as well as the length of that hole and the entry/exit profile. So there’s a lot that contributes to the actual flow besides just the hole size.

With all that said your suggestion is a much better solution imho, Personally I replace the stock #115 air jets with #110’s but the #98 should be fine as the idle circuit fuel #35 (.0135in) is ridiculously lean . Elegant solution there.

[Old Fogey]

A caveat to the article.
In my rebuilds I use the more readily available 6mm bore tubing. That bore can vary in size, it's only rubber after all, so there is a possibility of air leaks around the edges of the #98. How much that may a problem I don't know. The 6mm tube in the photo is a good fit.
You guys in the US using 1/4" should have no problems. That size is also not so readily available over here.
A better solution would be the not so readily available 5.5mm tubing. Honda specify 5.3mm..Hmm...try finding that!

[redglbx]

Old, still a nice alternative!

As an aside, my grand-daughter spent a semester there at Edinburgh last year and she sent us lots of pictures of her travels in Scotland, what a truly beautiful country and what a great history there, and she has commented many times on how great the people were, she loved it there,, wouldn’t be surprised if she moves there at some point,,,,you should be proud !