Carb mixture thumb screw swap

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Leo44
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What Bike or Bikes Do You Own?: Yamaha Tenere XTZ 600 1VJ (1986)
Location: Italy

Carb mixture thumb screw swap

Post by Leo44 »

Hi everyone,

I recently cleaned my carbs and had time today to put them on and fire the bike up, which means mixture screw adjustment came next.
I tried to reach the mixture screw but quickly came to the conclusion that no standard screwdriver could work, I then tried to 3D print some sort of sub-compact handle for a slotted 1/4 hex bit, that made the adjutment somewhat possible, but definitely not easy.

Looking around on the internet, I saw these mixture screws that extend out of the carb recess and act as a thumbscrew, for various carbs. Is there such a thing for our YDIS carbs?

Thanks in advance,
Leo
donnybach
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Re: Carb mixture thumb screw swap

Post by donnybach »

I’m sure I’ve seen some before. If you had a hobby lathe you could extend the standard one with an inserted piece. From when I was chasing carb settings, I carried (still do) a little ratchet with the 6.5mm adapter with a flat blade in. I can squeeze it In between the starter motor and feel and count turns out. The extended version would definitely be a lot easier. Can you compare them in pics?
Leo44
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Re: Carb mixture thumb screw swap

Post by Leo44 »

donnybach wrote: Mon Mar 09, 2026 10:52 pm I’m sure I’ve seen some before. If you had a hobby lathe you could extend the standard one with an inserted piece. From when I was chasing carb settings, I carried (still do) a little ratchet with the 6.5mm adapter with a flat blade in. I can squeeze it In between the starter motor and feel and count turns out. The extended version would definitely be a lot easier. Can you compare them in pics?
I wish I had one to compare, I can search a generic image online, like this:

Image

or this even

Image

I found some online for sale, but they seem like some chinese stuff off of AliExpress, I have no idea about thread size, pitch, o-ring size or if the metering needle is the right size and shape for our carbs
Scumfrog
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Re: Carb mixture thumb screw swap

Post by Scumfrog »

You could always try out one of the above can't be more than a couple of quid off aliexpress.

I got one of these. works ok.

Image
Leo44
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Re: Carb mixture thumb screw swap

Post by Leo44 »

Scumfrog wrote: Fri Mar 13, 2026 4:14 pm You could always try out one of the above can't be more than a couple of quid off aliexpress.

I got one of these. works ok.

Image
Right on Scumfrog, I just finished 3D printing myself one of those angled screwdriver

It’s a bit crude but it should do its job, I’ll test it on the bike ASAP
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