Idle Air screw Driver

[ALBeix]

Idle air screw driver. .jpgAs others have observed getting into the space under the carbs to adjust the idle air screw can be a challenge. There does not seem to be any commercially made screwdriver small enough to fit. At discovering this for myself I decided to make what I needed. The bit is a small slot screw driver with a six sided shank designed to be used in a drill or impact driver. The nut is one I had in my nuts and bolts collection as it happened it is a nut with a cast in washer, which turned out to be helpful as I will explain in a moment.

As found the bit would not fit into the threaded hole but I figured that with some judicious hammer work I could make it fit. Drove it in by placing the nut washer side down on my vice set such that the bit would go through the hole starting with the blade. Once I had it driven through enough I cut off the remaining shank with a cut off wheel.

I tried it out and it works a treat but I had no real sense of how far I was turning the screw so this is where the built in washer on the nut became important. In order to get the necessary tactile feedback I filed the round washer into a four sided square with slightly rounded corners. Now I can tell when I have turned it every quarter turn.

I now have a custom made motorcycle tool in my bike tool kit at a cost of Zero dollars Cdn (US dollars at par - with no penalty in this case)

[stl360+450]

That's pretty cool. I've seen another solution, but I don't know if these are available for all carbs (probably not). Basically it's an extra long replacement mixture screw with numbered sides that you can turn with your fingers.
Screenshot_20211109-182223.png

[ALBeix]

That's pretty cool. I've seen another solution, but I don't know if these are available for all carbs (probably not). Basically it's an extra long replacement mixture screw with numbered sides that you can turn with your fingers.
Screenshot_20211109-182223.png

That is indeed cool. but I suspect more expensive than my little mini Screwdriver.

[stl360+450]

That is indeed cool. but I suspect more expensive than my little mini Screwdriver.

I would have to agree with you there! Looks like those screws go for about $8-10 US if you can find one that fits your carb.

[LongDistanceRider]

I would have to agree with you there! Looks like those screws go for about $8-10 US if you can find one that fits your carb.

Unfortunately the VB series carbs mixture screw faces straight down with @4" of clearance to the top case.

[ALBeix]

Unfortunately the VB series carbs mixture screw faces straight down with @4" of clearance to the top case.

Precisely the reason I came up with my little screwdriver thingy it is only about 1/2" long in total.

[Richard Pitman]

I bought one of these Morgan Carbtune bevel drive screwdrivers to adjust the mixture screws on the four carbs on my Hornet. Also worked well for removing float bowls in situ on that bike, 4 JIS screws on each float bowl.

For some reason, it's no longer listed on the Morgan website. Useful tool but a bit pricey.

[ALBeix]

I bought one of these Morgan Carbtune bevel drive screwdrivers to adjust the mixture screws on the four carbs on my Hornet. Also worked well for removing float bowls in situ on that bike, 4 JIS screws on each float bowl.

For some reason, it's no longer listed on the Morgan website. Useful tool but a bit pricey.

I do have a bevel drive screwdriver but I fine it awkward to use whereas my DIY solution is very easy to use. It would be even easier of the screw had either a JIS/Phillips or a Robertson head that would capture the bit as opposed to a slot that the driver can easily slip out of.

[Yakeye]

Idle air screw driver. .jpg.

I now have a custom made motorcycle tool in my bike tool kit at a cost of Zero dollars Cdn (US dollars at par - with no penalty in this case)

Love it !!!!....as they say "necessity is the mother of invention"

[deckeda]

Here's mine, a 1/4" "long" socket (1/4" drive) and a flat blade tip.

IMG_3680.JPG



I need the length because the screw on mine is ensconced up in a channel formed by the edge of the float bowl. For gription I doubled over some painter's tape to make it double-sided sticky.

Of course, these driver bits cost nearly nothing. If I was smarter I'd J-B weld one to the screw and leave it hanging there forever. Why? It would be easier to have the socket find the bit than the bit to find the screw slot, especially when the bike it running and vibrating and I'm trying not to get burned against the cylinder head. My bike has the added challenge of navigating against a large plastic ("phenolic resin?") heat shield also.

Maybe the $20 replacement adjuster isn't such a bad idea in that context.