Bonneville America Forums Forums Technical Forums Performance Mods NEEDLE FOR CARBS

I HEARD SOME STORYS ABOUT SOME PEOPLE PUTTING NEEDELS IN FROM THE THUXTRON CAN ANYBODY TELL ME HOW IT WILL HELP MY BA I HAVE 2 SHIMS ON MY CARBS NOW AND 130 MAINS AND 1 STEP OVER ON MY PILOT JETS.

WELL, THE NEEDLES...oops sorry, I was yelling.
The needles have a big effect on the flat spot in the mid throttle position a lot of us feel.
It also depends on what year and engine your bike has. If it is an 865cc model, it's already a Thruxton needle in the carbs.
It's kind of a hit and miss thing as the carbs vary from bike to bike too, some like the different needles, some don't.
You can slways start with the TBS needles and then try the Thruxton ones and see what your best seat dyno says after trying all three variations.
It is a quick easy job to swap the needles, just pull the gas tank and the tops off each carb. be careful ewith the rubber diaphrams and make sure they go back on nice and square.
My site has a lot of info on this - check out the shim part, shows it pretty well eevn though it i a slightly different mod. Dinqua.com

I REALY DONT HAVE A FLAT SPOT I JUST THOUGH I COULD GET A LITTLE MORE PERFORMANCE OUT OF IT I HAVE A 02 BA CAN YOU TELL ME HOW TO KNOCK THE BAFFLES OUT OF MY STOCK MUFFLERS I HAVE D@Ds ON IT I REALY DONT LIKE THE WAY IT SOUNDS AND ONE SIDE HAS A GOLD TINT TO IT

Can't help with the D&Ds, sorry, sopmeone else should chime in though.
Sounds like you need to sync the carbs after you set the pilot screws using the turn as it idles method.
Start the bike, set the idle a little high (1200) adjust each pilot screw until the idle starts to drop a little, then back it off a pubimeter, do other side the same. Then sync carbs.

Dinqua's the expert, but I thought I would add this:

A lot of guys have switched needles, but whatever you do I would recommend getting a dyno run including fuel mixture measures before you start.

I had the TBS needles in when I went to get my dyno and it turns out I was WAY rich - I don't remember the ratio, but it was bad. The taper seems to have a lot more effect than a shim or two through a certain part of the throttle position range.

I ended up dropping back to stock needles and adding a shim - I did have better response w/ the TBS needles in but I would rather get another 6-8 MPG and be closer to the ideal mixture ratio.

NOTE 1: I think part of my problem is that I can't get enough air though the mod'd airbox and unifilter - I think that's my current bottleneck but don't want to spend the money for the Freak.

NOTE 2: Jacking w/ your carbs and air intake system is the probably the most time consuming and frustrating task you can do on this bike - there are a LOT of variables that come into play. Again, recommend putting some $ aside for dynos, and finding a good dyno technician and use his advice as a starting point before you jump into anything yourself. (the chart will tell the people who can help on this forum more than just what you feel or suspect)

Let me add some more info:


Which comes from this web site for CVK carb tuning.
The carbs on this site are CVK40, which are identical except for throat size to our stock carbs.

Use the throttle position with tape and marks and you can quickly dial your carbs in lickity split. Sorta like tippity tapp tapp.

About the D&D's. I had them and didn't like the blapblap sound either- I thought I was the only one. I bought some America pipes. they came withthe two end baffels removed and the other two baffels drilled with three 3/8" holes. the performance was noticibly reduced. I removed the remaining baffels- but left the difussers in. Performance is not comprobable to the D&D, baybe just a little less. To remove the baffels, I just took the pipes off the bike, acquired a long steel pipe that fit inside the exhaust, and a 3lb hammer. I'll tell you, there has got to be a better way. Every whack made me cringe and I am suprised it came out all right. Then there is the whole geting the bent up baffel out of the exhaust. It's not fun. I didn't tear anything up, and I couldn't be happier about the sound. I get tons of comments about the sound of my bike. The only bummer is the 07's swapped pipes between the SM and the AM. I had a one off... for about 3 months. The baffels are a round solid plate welded to the exhaust pipes with a 4-6 inch 3/8"(est) tube throught them, and the tubes are staggered/offset from one another. And yes, my bike is loud, but not as loud as the D&D's, but just by a hair (choose your favorite one).

I KNOW ABOUT TRYING TO GET THE BAFFLES OUT I BEAT MY GUTS OUT TRYING TO GET THEM OUT I JUST THOUGH THEIRS GOT TO BE A BETTER WAY

Dude, we can hear you! There's no need to shout.

(aka, turn off your cap locks!)

Ok, folks -- maybe this is a stupid question -- where can one get the TBS needles? Is there an online site? If so, what's the part number?

--Jaeger

Your local Triumph Dealer should be able to order them for you...part number I cant remember but its in the "Tech Vault"

Got it. Thanks!

--Jaeger

For all my stuffing around with std needles, std needles and shims, TBS needles, TBS needles and shims, main jets, pilot jets.....I reckon a 43 or 44 pilot would suit my bike just fine - they don't make 'em! After all the above, I'm CERTAIN that an inbetween size from the std 42 to the first available size of 45 would be BRILLIANT.
My ten cents.
Irrelevant to original topic. Sorry.