Bst40's

[manden]

Hello mates.

 

Has anyone ever tried to straighten the needles of their carbs?

I'm thinking about giving it a try, so if it's a bad thing to do them please stop me before I start modding them

[Gixer1460]

Firstly why and how did they get 'bent'? Not sure i've ever heard of anyone bending needles!

Bearing in mind how accurately they are machined / made, any deviation is likely to touch the jet causing increased wear, so i'd probably say no - but you've nothing to lose by trying!

[Gsxrsam]

Tis the plastic piece that holds needle that wears out and tilts needle.....

There is a alloy replacement...

 

[Jaydee]

 

[Baron]

I just cut flat spot to the plastic washers with side cutters. Works like a charm.

[manden]

I'm doing it Tuesday. Happy plinger day

Edited September 5, 2021 by manden

[manden]

On 9/2/2021 at 11:16 AM, Gixer1460 said:

Firstly why and how did they get 'bent'? Not sure i've ever heard of anyone bending needles!

Bearing in mind how accurately they are machined / made, any deviation is likely to touch the jet causing increased wear, so i'd probably say no - but you've nothing to lose by trying!

Standard the needle is angled against the emulsion tube for "silent operation in idle"

[Gixer1460]

8 minutes ago, manden said:

Standard the needle is angled against the emulsion tube for "silent operation in idle"

So the 'needle' isn't bent - its how it is fixed makes it wonky! And i'm not sure anyone was serious when describing that to ensure it was "silent operation in idle"

That's the most BS excuse ever! Everyone since carbs were developed knows the needle should be essentially be centred in the jet. A pretty reliable method just uses a spring behind the spring to hold it down but allow a degree of lateral movement / wobble to account for the slide moving.

[Oilyspanner]

I've spent several years peeing around with the needles, worn needle jets/emulsion tubes etc. My findings back up what G1460 said.

You need spacers that hold the needles central and within spec carb slide guides, mine were worn, too much slop and the needle will be moving all over the place, causing wear and incorrect fuel monitoring.  You'll notice a 0.05 mm difference on the needle/needle jet orifice gap.

[manden]

It's how suzuki describe why they did it.

[manden]

Run these or standard single hole slides?

[manden]

Straight needles now

[Upshotknothole]

On 9/8/2021 at 9:54 AM, manden said:

Run these or standard single hole slides?

Depends on the jet kit, dynojet plugs them, factory pro doesn't.