Chris59 Posted November 7 Report Posted November 7 (edited) Hello, I'm playing with SU carbs on a 74 standard US TR6 (they were already fitted, I haven't got the Strombergs). The actual needles (fixed) are "ST" : I'd like to find fixed needles with a similar profile to BAM (who are "floating" needles), but it's impossible to tell if a needle is fixed or biased by using Mintylamb website. Who can help me ? ? Cheers, Chris Edited November 7 by Chris59 Quote
BlueTR3A-5EKT Posted November 8 Report Posted November 8 Why not remove the top hat bit off a floating needle? It is only pushed onto a knurled surface. This removal can be done with a dremel or careful filing. I’ll poke about in the garage to see if I have a pair of BAM needles Quote
Chris59 Posted November 8 Author Report Posted November 8 2 hours ago, BlueTR3A-5EKT said: Why not remove the top hat bit off a floating needle? It is only pushed onto a knurled surface. This removal can be done with a dremel or careful filing. I’ll poke about in the garage to see if I have a pair of BAM needles Hi Peter, how are you ? To be fair, I never thought if it can be done 🤫 ! It's seems to be worth checking on a old floating needle, it might work. Quote
BlueTR3A-5EKT Posted November 8 Report Posted November 8 Pete Cox got a batch of SM needles produced with the top hat so they would fit in modern HS6 carbs that had bias needle pistons. That was to service the TR market in the 1970’s. Quote
DRD Posted November 8 Report Posted November 8 16 hours ago, AJAS said: Try Burlen fuel systems They also have a really good needle comparison tool in the technical area on the website. Quote
Chris59 Posted November 8 Author Report Posted November 8 (edited) 2 hours ago, BlueTR3A-5EKT said: Pete Cox got a batch of SM needles produced with the top hat so they would fit in modern HS6 carbs that had bias needle pistons. That was to service the TR market in the 1970’s. SM needles seems to have an interesting profile, Peter. I might have a set in my spare needles' box. "DRD", my computer can't open Burlen comparison tool. Edited November 8 by Chris59 Quote
BlueTR3A-5EKT Posted November 8 Report Posted November 8 BDB was the. Standard needle for Triumph 2500TC and S which had twin HS6 carbs on essentially the same engine as yours, including the cam. (311399) Compression ratio would have been near 9 to 1 as against wherever the American spec was in 1975. 8 to 1? Your TR exhaust is twin down pipe, the saloon car had a single pipe, same as pre ‘72 TR6. No emission stuff on the saloon engine.. Quote
Chris59 Posted November 8 Author Report Posted November 8 It might be a bit rich for this engine, as, you are right, the compression ratio is rather low. I had a quick look since your previous message : I've 2 sets of SM needles, who have the advantage to be fixed. BAE (biaised) seems to be also an interesting profile, they might be the one I've got in one of my TR6s (ex 2500 PI saloon engine with 2 SUs from a TR7), I'll check this Monday. Quote
DRD Posted November 8 Report Posted November 8 3 hours ago, Chris59 said: SM needles seems to have an interesting profile, Peter. I might have a set in my spare needles' box. "DRD", my computer can't open Burlen comparison tool. I found it worked OK in Chrome. Quote
Chris59 Posted November 12 Author Report Posted November 12 I get a reply from Burlen (nice guys btw !) : they think it's worth trying SK needles. That's the route I'll follow if SM are to rich. Quote
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