Which SU Needle?

[chris_bates]

I have recently changed the 1098 engine in my pick up from one with a 940 head to one with a standard head. (The former engine needs a rebuild so the present set-up is temporary). The SU carb is a 1.5in HF4 fitted with an AAS needle. Although it runs sort of ok, the engine doesn't sound quite right and is jerky at certain revs.

What would be a more suitable needle?

Thanks

Chris

[chrisryder]

I ran an AAA in mine with the same set up, with no problems.

[bmcecosse]

AAA for a 940 head - but will be far too much fuel for a standard head. What carb is it - and what manifold?

[chrisryder]

AAA for a 940 head - but will be far too much fuel for a standard head. What carb is it - and what manifold?

He's said it's a 940. And has also said it's a 1.5 inch HF4. Which I presume to be a HS4.

[bmcecosse]

No -it WAS a 940 head, but NOW it's standard....and manifold etc???

[chrisryder]

Oh, you're right. Still, I'm still running the AAA now I've gone back to a standard head. Possibly a little lean at high rpm though. Gets a bit warm above 70mph.

[bmcecosse]

I doubt it is LEAN!

[chris_bates]

Thanks for the replies.

The carb is an HS4, (getting confused with HIFs )

I'll try the AAA needle and see how I get on, although my run today did not seem to replicate the rough running problem so it may be the latest lot of petrol has now worked its way through the system ???

Thanks again.

Chris