stupid question needle jet related

[waktaylor]

If I want to enrichen my mid range do I need rich needle AND needle jet or just richer needle?

Around 6k rpms cruising my EGT went to 1250 real quick so I let off. Main seems just a size too large for max power and low end is great.

EDIT:
VM30 with 159-p-5 needle jet and 6F5 jet needle in richest position.

[Czakky]

I believe the jet effects more higher up on the throttle but I'd personally move needle clip first. Then go up on jets as needed.

What carbs are you using?

[waktaylor]

VM30 with 159-p-5 needle jet and 6F5 jet needle

6k rpms is pretty high in the rev range and I have the clip in richest position.

I believe the jet effects more higher up rev range but I'd personally move needle clip first. Then go up on jets as needed.

What carbs are you using?

[Czakky]

Sorry I was doing eight things at once. I edited my original response. I meant higher throttle position.... which is a strange way of putting it. But either way. Needles are way less linear how they are designed/shaped. I would play with needle jets first, but there are many smarter folks on here than me.

[Alain2]

If you are lean at 7/8 throttle coming off a rich main you need a richer nozzle.

If you are lean 1/2 throttle you probably need a richer needle.

[quocle603]

Drop a notch to rich your mixture. Raise a notch to lean it out. A lot of people start at the middle.

I was struggling with tuning my carbs, could not make it to the main jet. I kept on fouling plugs before getting to WOT and found that the remedy was to go up a notch from the 4th position (second from the bottom) to the 3rd (middle) position. Then I was able to properly jet to get to WOT.

[teazer]

If you are lean at 7/8 throttle coming off a rich main you need a richer nozzle.

If you are lean 1/2 throttle you probably need a richer needle.

Are you sure that's correct.  Larger needle jet has a proportionately larger effect at small throttle openings because the annular orifice is so small there and any change has a big effect whereas at WOT, the change in area is small compared to the baseline.  That shows up on the Mikuni handbook as maximum impact at 25-30% throttle with zero effect at WOT.

Change in clip position has impact at slightly higher throttle "peaking" at 50% and still some impact almost all the way to WOT.

What I think the OP needs is a different needle with sharper second taper to richen up the 1/2 to 4/4 throttle. 6F5 is quite a lean top end.  Try a 6F9 and see if that helps.  It's a single taper but might get you close enough.  If not, try 6DP1 which is much richer.

[Alain2]

If you are lean at 7/8 throttle coming off a rich main you need a richer nozzle.

If you are lean 1/2 throttle you probably need a richer needle.

Are you sure that's correct.  Larger needle jet has a proportionately larger effect at small throttle openings because the annular orifice is so small there and any change has a big effect whereas at WOT, the change in area is small compared to the baseline.  That shows up on the Mikuni handbook as maximum impact at 25-30% throttle with zero effect at WOT.

Change in clip position has impact at slightly higher throttle "peaking" at 50% and still some impact almost all the way to WOT.

What I think the OP needs is a different needle with sharper second taper to richen up the 1/2 to 4/4 throttle. 6F5 is quite a lean top end.  Try a 6F9 and see if that helps.  It's a single taper but might get you close enough.  If not, try 6DP1 which is much richer.

Let's try this:
If you are lean at 7/8 throttle coming off a rich main you need a richer needle .

If you are lean 1/4 - 1/2 throttle you probably need a richer nozzle.

Sorry about the confusion

[waktaylor]

Fellas my question was far more rudimentary and I think I've assumed the answer.

Let me ask a different way.

Do you change jet needle and needle jet in combo or can I simply swap jet needle only? Probably a stupid question that I believe I've found the answer to.

[Alain2]

You can change them individually.

[teazer]

Alain2 is right. 

Change just the needle if that's the change you want.  If you don't have needle dimensions, PM me and I may have the spec's here.  But try a 6F9 with your current needle jet and see how that changes things.