HS6 Carburettors- Jet Positioning

[James R]

Hi All

I am hoping someone can give me some information on the position of the jets within the carburettor body at certain points please……just as a check point for me and to allow me to see what I have within my set up…

1. When the mixture nuts are fully wound up, should the top of the jet be flush or proud of the body when viewed with the carb chamber removed?

2. When the the mixture screws are wound out to the 2 full turns (12 flats) as the start point for mixture setting etc, what position should the jet be in again viewing with the chamber removed? I am told that it should be around 1/16th below the body? Sound about right?

I appreciate that this isn’t an exact science but I assume that there is a rule of thumb to work to….

Any information/views appreciated…

Thanks

[triumphdolomiteuk]

https://forum.triumphdolomite.co.uk/vie ... =4&t=33830

[soe8m]

1,5mm below the venturi bulge is a good start. When that is already way too rich at idle it's time to replace the jets and needles first before other attempts are made to adjust the mixture.

Jeroen

[James R]

Thanks

The Jonners article I have but it doesn't contain any details on the questions I have asked unfortunately.

[MIG Wielder]

Hi James, I have the body of an old SU HS6 here so I measured it up.

It is a non-waxstat model though, if that makes a difference.

With the jet fully wound up the top of the jet is above the bridge piece by +0.52 mm

6 flats down measures 0.32 mm below the bridge piece.

12 flats down measures 1.12 mm below.

18 flats down measures 2.27 mm below.

So the pitch of the thread of the adjuster looks like about 0.92mm.

HTH,
Tony.

[yorkshire_spam]

Not sure about HS6, but the starting point for tuning HS4 is the jet level with the bridge, NOT the jet wound fully up.