Carb slider needle upgrade

[Alan McLean]

Hi All, was in the process of doing the slider needle mod when I discovered that my needles have 5 slot’s not 3 and that the rear carb was already in slot 3 but the front carb was in slot 4!!! Any suggestions as to what slot’s they should be in and should front and rear be the same?

[♠️ M77]

If 1 needle has 3 grooves –> the other one must be in equal height.  (could be also 4 or 3rd slot)  ,

either way a digital caliper can measure the needle height (AFTER) both are fitted on the black piston slides.  you want both carbs equal in all cases.

middle of 3 grooves is factory. on a factory 3 groove needle.

[Alan McLean]

Marcel, both needle’s have have five ring’s my concern is that one is on the third ring (rear carb) and the other is on the fourth ring (front carb) should they both on the same ring and should it be on 3 or 4 !

[♠️ M77]

Three.

The furthest the needle is out of carb the richer it gets.  You dont want it too rich 😉

[Alan McLean]

[Alan McLean]

I understand that, I was wondering why the two needles are set at different levels one on the third ring and the other on the fourth. You can see the difference in the image’s.

Should they both be on the third ring?

[♠️ M77]

In either case, you want them at equal height 🙂  .

The needles themselves should be equal height on the table.

Then fit on the slides using 3rd or 4th groove to suit the bike.  Test ride. And do the usual plug check for a hint of lean / rich.

[Alan McLean]

Thanks Marcel, I will set them both in the third slot and see how it performs.

[Max]

Hi Alan,

do you remember the result?
My setup was exactly the same, so seems like the carbs will be shipped as you have shown.

I think the reason for the different needles is that the rear cylinder is supposed to run a bit richer than the front one, with the same jetting.

Saludos
Max

[Author]

Posts

[Alan McLean]

Hi All, was in the process of doing the slider needle mod when I discovered that my needles have 5 slot’s not 3 and that the rear carb was already in slot 3 but the front carb was in slot 4!!! Any suggestions as to what slot’s they should be in and should front and rear be the same?

[♠️ M77]

If 1 needle has 3 grooves –> the other one must be in equal height.  (could be also 4 or 3rd slot)  ,

either way a digital caliper can measure the needle height (AFTER) both are fitted on the black piston slides.  you want both carbs equal in all cases.

middle of 3 grooves is factory. on a factory 3 groove needle.

[Alan McLean]

Marcel, both needle’s have have five ring’s my concern is that one is on the third ring (rear carb) and the other is on the fourth ring (front carb) should they both on the same ring and should it be on 3 or 4 !

[♠️ M77]

Three.

The furthest the needle is out of carb the richer it gets.  You dont want it too rich 😉

[Alan McLean]

[Alan McLean]

I understand that, I was wondering why the two needles are set at different levels one on the third ring and the other on the fourth. You can see the difference in the image’s.

Should they both be on the third ring?

[♠️ M77]

In either case, you want them at equal height 🙂  .

The needles themselves should be equal height on the table.

Then fit on the slides using 3rd or 4th groove to suit the bike.  Test ride. And do the usual plug check for a hint of lean / rich.

[Alan McLean]

Thanks Marcel, I will set them both in the third slot and see how it performs.

[Max]

Hi Alan,

do you remember the result?
My setup was exactly the same, so seems like the carbs will be shipped as you have shown.

I think the reason for the different needles is that the rear cylinder is supposed to run a bit richer than the front one, with the same jetting.

Saludos
Max

[Author]

Posts