Which Stromberg Needle?

[Mileso]

Hi,
Had my S4 on twin Strombergs engine rebuild late last year. Goes really well but very rich when diving keen - to the point of being nausiating on times! (fine at lower revs). Engine builder reckoned needles were at end of adjustment so I guess they could be worn and need replacing?

Question is what should I have - would they be marked? I think I have overhead balance pipe so should be B2AR from manual extract below?
Your expertise appreciated.
Miles

[m750rider]

Yes, needles can wear and will need to be replaced.

Yes, they are marked, relatively simple to pull it out by removing the carb top to get to the needle and mounting, and you will see what you have.

FWIW I use a fixed B1Y in a 69 S4 SE with slight upgraded cams. It would be leaner at low throttle and richer at higher throttle than a B2AR.

Give Ken Gray a call at Dave Bean Engineering for his advice - he's really good.

[tonyabacus]

Miles
Check on the forum for”Stromberg damper spring differences” posted Jan 2019, which contained some useful information. I don’t know how to show the link.

Also it may be worth talking to one of the Triumph suppliers such as Rimmer Bros as Triumph were a big user of these carbs, the supplier may be able to supply a needle chart which will show the differences along the length of the needle, so you may be able to find a more suitable needle. However the best way of course is on a rolling road, but again find one that is used by the Triumph boys, only because the operator is likely to be more familiar with the vagaries of these carbs.

I think there is also a conversion kit for these carbs which allows more variable adjustments, again talk to a Stromberg supplier.
Tony

[Mileso]

The plot thickens. It appear I have B1DK needles so not sure what's going on. If I read i the charts right then b1y etc would make it even richer as mine are 'fatties'.

[m750rider]

Dave Bean catalog indicates that the B1DK needle is for the 907 emissions engine, not yours. And it could be worn - have you measured it to check?

Based on my experience with a 69 Stromberg engine I would just go with the non adjustable B1Y.

[RogerFrench]

M750rider, your Federal car is a very different kettle of fish from the UK car in question. Fixed needles and adjustables are not a direct swap.
Don't forget that jets wear too, OP!