Bonneville America Forums Forums Technical Forums Performance Mods Anyone ever figure out the Tbird Sport needles?

I think I remember someone talking about using thruxton or Tbird Sport needles in their carbs. Anyone do that?

I put the TBS needles in my america. The dyno dude says they are slightly rich but they really fixed a big flat spot I had at around 3000rpm. I'll give 'em the thumbs up!

benny,
I have the TBS needles. They improved the throttle response, IMO. I think it was Dinqua who was researching the Thruxton needles.
The TBS needles have a definite taper to them while the stockers look like finishing nails.

I put them in DanB's Speedy and he tells me they work great. He was already jetted up for his aftermarket pipes, too.

I'm surprised that someone with a micro-lathe hasn't made some custom ones yet, either from scratch or by modifying original stockers.

Would anyone have a part number for them. I'm doing a little work on my Speedy and want to try them?

Jango

TBS needles are N3RF and the Thruxton neddles are NBZT.
Hope this helps!

Benny,
I currently run with the TBS needlse, Triumph part #T1241024.
I have a set of the Thruxton needles I am going to try if the snow ever melts away.
I Will get the part# tonight when I get home if you want it. The needles are about $6 each so no biggie.
The main difference is the taper on these needles. Our stock needles are basically nails with straight sides and minimal taper to them. The TBS needles are slightly longer but have a very definite taper to them. I ran a dyno and got a minute dip in the 3500-4k range and them put in the TBS needles to eleviate this. It feels way better and actually may be running a tad rich now. I am going to go the big bore route next month whilst laid up for the ice age and will then try the Thruxton needles with that setup. They seem to be a bit slenderer with similar taper compared to the TBS'ers, which appears they will give even more gas. I will keep ya posted to the results after this is all done. I will have to let it break in first then get it dynoed again for poops and grins.
Sigh, only 6 more months of winter here in the great white north. 3' of snow, my snowplow guy coming by everyday now and sometimes twice, -5°F, but hey, the suns actually out today and it's gonna warm up to 9°F by this afternoon! Yahoo, a heat wave, lets go swimming!

Thanks for the reply guys!! I figure I'll be re-jetting with my K&N's and pipes anyway... It'll be a good excuse to swing by the dealer and check out some shiny bikes. Sounds like they will run a wee bit rich, but at the same time fixing the weak link!! Thanks guys

Benny

You must try to match your inflow with your outgo, grasshopper.......

Yes Sensei. My outflow and inflow will be in harmony.

Here is the link to my original post about the TBS needles.


I had helped a friend put a FactoryPro jet kit in his 1998 TBS and had the needles laying around so I figured why not. It was the best thing I ever did to my bike short of buying it in the first place!


TBS Needles

thanks Deuce!

Just thought I'd add that I installed the TBS needles as well, and it cured my flat spot (3K-4K rpm roughly). I believed I was a bit lean to begin with, so I didn't make any other changes. I really can't be sure where I am at now, though, it may be a bit rich, just don't know. But, I know it runs far better than it did stock...

I finally dug out the Thruxton needles, the Trump Part number on the bag says T1245031 and they are stamped NBZT with the B being a weird little B with a line in the front of it. The B is half the size of the other letters as well.
If you order them, go by the trump part number anyway, most shops will give you a blank stare if you ask for a NBZT needle jet. And don't forget to get 2 of them, one for each carb eeh?

So Pat, seems like everyone loves the performance, but they are running a little rich with the needles. Is a slight rich condition an OK compromise to smooth power delivery?

Dunno about running rich. The plugs look just about right, still a tad lean if anything. This may be one of those cases where different bikes in different areas with different setups are all going to respond ... well, a little differently!

Ok, so where does one get their hands on these TBS needles? Dealer only?

Well, Dinky, it's a month later. Do you have your big bore kit yet? (The snow plow man brought it, right?)

And a sure cure for a slightly rich condition is a killer electronic ignition and wider spark plug gaps. Makes more power, too! Hmm, that gives me an idea for a new thread....

Benny,
Sorry, a little slow on the follow up. But, yes, running a little on the rich side is way better than the lean side. The richness will cause the plugs to be a little darker, burn more fuel but it also keeps the motor a tad cooler. Not a big deal unless it gets too rich, kind of a fine line there.
With my current setup; freak/160 mains/42 pilots/Tbike pipes /TBS needles it is a tiny bit too rich. The Thruxton needles would necessitate dropping the mains down about 3-4 steps due to the big increase in WOT fuel from the Thrux needles (even more taper and fuel flow than the TBS needles).
The better taper will increase the fuel flow at the WOT point which is also the same as the mains jets.
Now, After I do the Big bore I will most deffinetly use the Thruxton needles and drop the mains down to about 130's again. Then do some plug checks and some dyno runs after a breakin period.
I'll keep ya posted.

So you're saying tbs needles unless I go big bore, which I'm not...

No, that's not what I meant to imply. The TBS needles are richer than the stock, the Thruxton are even richer. This is due to their tapers and length. It's like changing needle clip positions (shims in our stock setup) and they allow you to "adjust" the point of rise and flow of the fuel in differnt throttle positions. The EPA made this necessary by having trump put the nails in the stock carbs. They just downright suck in my opinion. (The needles and the EPA)
The main benefit would be the elimination of the mid range waver in hp. The Thrux are more extreme than the TBS. It's kind of a shell game. Try them and see which ones work best for your particular bike. Since there seems to be huge variations in these carbs and setups on eveyone's bikes, you should try both to see what is best for you.
If you get too rich, you can play with the main jets to dial the needles in better too. There are a lot of good references out there that show exactly where the needle taper comes into play. If you find the TBS are better for you, or vice versa, then I'm sure you would have no problem selling the other needles here to get your money back.
Mind you, all this is mostly for the really anal tuner, you can get your ride to run just fine without all this dicking around too. I just like to play, I know how to, so I do. Just a personal thing.

Ok thanks Pat. I guess why I keep asking simple questions is that I will be doing the whole Freak/K&N thing soon, and while I have the carbs out I would like to do the needles and jets at the same time. Rather have a one shot deal, ya know? So I think I'll start with the TBS needles, and hey if I have to adjust the jets or shims or something, then so be it. I have the good carb screws, so removing the bowls and what not isn't that big of a deal.

Here's a graph showing the pilot/needle/main relationshiop. I think I've posted this already in another thread, but adding it in here should benefit the discussion.



From what I've read in the various forums, the Thruxton needles seem to be best suited for those who've taken out the airbox, and the TBS needles are good for those who've removed the snorkel(s). Of course YMMV.

Thanks Sal, that's exactly the chart I was thinking of. Clarifies this discussion quite nicely.

Hi,
My only problem with changing over to TBS needles is finding them. No dealer stocks them and it takes a week to get them, so plan ahead. I called 7 dealers and was willing to drive 120 miles to just pick up a set. No! They are not stocked and I almost got in an argument with the closest dealer parts manager. He said he couldn't believe I wanted to modify anything on an America. I told him Triumph engineers had a great design, but it needed a little adjusting and the bike is anemic and constipated to Brit riders of any age. He said he'd order them but was sure it would void my warranty. My warranty's been dead for nearly a year.
Dennis

Yeah my warrenty is way gone now too.

So i've been reading this thread, and being new to customizing, i'm a little confused.....

I have a speedmaster, that thanks to Brent... I've decked out with alot of Newspeedmaster parts...(mostly cosmetic)

(performance wise) I have put on an 18 tooth front sprocket on and NGK Iridium spark plugs. i also have a Freak airbox removal kit coming.

So here are my questions, with the freak on the way i want to change out the needles since i have to re-jet anyway. I was orginally going to go with TBS needles with .33 shims, but now with all the talk of Thruxton needles i'm not sure. What is better for my speedmaster? If i go with Thruxton needles do i need shims? and what main/pilot jets do i use with them?

Current setup:
'04 speedmaster
AI removed
Stock Pipes
Stock Carbs
Stock airbox (for now)

not sure about your question chuck, but get rid of those pipes before doing everything else, with the stock pipes you will not get nearly the performance with a nice set of aftermarket ones.

Frank

I have the Triumph off roads, 125 mains and the air box snorkel removed. Can I just put in the TBS needles without any more adjustment?

Geez, give me a break: How the heck would a dealer know the carb needles were changed. I've only been in one shop that might remotely even check. Someone just posted their dealer replaced his wiring harness to discover a fuse was blown. Yeah, these guys are real sharpies....

Hey Chuck, I think nobody has actually done and tested the thruxton needles yet except maybe Pat. But I think your idea with TBS needles and shims should be a pretty good starting point...

Well i really don't have the money right now to change out hose stock pipes... I figured tearing out the airbox and putting in new jets and needles would be good till the riding season goes into full swing.

So does anyone else agree with Benny, that a good starting point for me would be with the TBS needles and shims? Or go with the Thruxton needles?

I'll bring all my needles down to Georgia this May. They take about 5 minutes to swap out. We can let people try the different ones and see what we get.

oooo sounds like fun:) So Pat you do all your re-jetting with the carbs on the bike? I have the carb screw kit so it shouldn't be a problem...

These are just the needles, just requires popping the tops off the carbs, 5 minute job.
Besides, my carbs are sitting on my bench right now so they're prettye asy to get to. I will also take the time to remove that nasty little T filter in the fuel line. I'll go ahead and add one of the purty inline ones like Gary James has.
Still working on the Jimmy from my brother. It's about a 99.9% certainty now, looks good. So it will be me and my girlfriend, (most likely) you and room for another. I will get the 12 foot open trailer to save on gas. It should hold 4 bikes easily. Just chip in a little for gas and trailer rental? My GF smokes so we'll probably take a lot of breaks along the way. Most likely take the slab too.

Oh yeah, needles in the top... Jets you need to take the float bowls off tho right? A little trickier...

As for the trailer, sounds good to me man. Happy to chip in some gas/trailer money. When the time comes closer we'll have to figure out a meeting point somewhere a long the way. Thinking of riding to Deleware to a friend's place after work one night, meet up along the way the next day somewhere.

I am, this week putting the Thruxton needles in my TBA. Will be dyno tuning and I will let all of you know how that goes.

I have the Freak w 160s (may have to change these) 42 pilots, Bub Slashcuts, Iridium plugs.

Should be interesting...

"Hey Chuck, I think nobody has actually done and tested the thruxton needles yet except maybe Pat.'

DanB on this forum has had them in his Speedy for a couple months now (I put them in, in fact). He's got Bubs and a modified air box. The carbs were rejetted by the selling dealer over in Cal. in conjunction with the pipes installation, when he bought the bike in Dec. '03,

The needles got rid of the mid range bog that had existed since day one.

Matt... adding the TBS needles to you setup should be about perfect. I've got 128 mains otherwise our setups are the same. I just adjusted my cam shims and had the plugs out and after about 10000 miles with this setup they look perfect. You'll love the change!

Hey Dean or DanB, do i need to put shims in with those Thruxton needles..?