Does any one have a photo of a Thruxton needle beside a TBS needle?
('03 790cc America)
I have removed all snorks, cut a round 60mm hole in the dividing wall between chambers in the air box, and tuned to 45 pilot, 140 main, TBS with one small shim. It hammers along no worries (and sounds cool too), but is running a little rich even after I have tuned it in for best available('bout 3 1/2 turns from memory) The pipes have black soot after a ride (unlike my mates with the same bikes) and the plugs come out black - but not wet. I've done 4,300kms like this am obviously I'm almost happy enough.
I'd rather rich than lean of course, but would like optimum tuning, for economy (I hate being the first to switch to reserve on our long rides) AND performance.
If I put the 42 pilot back in it backfires through the carbies (too lean) with them in it sometimes idles high for 10 to 20 seconds or so before dropping to a very low rev. (too rich) I really wish I could get a jet BETWEEN 42 and 45. (Incidently I bought another set of 42's and a 0.43mm drill bit and tried to drill them - there is nothing like factory machining - I was not successful!) If I remove the shim I have a small flat/lean spot at about 1/4 throttle (noticable in top gear on the hiway). If I put the original needle back in I have to add 5 shims to remove lean spots at the same throttle position.
Now to my question - does the Thruxton needle profile lie between the standard and TBS, or is it going to provide more fuel than the TBS.
I could buy the needles, remove a TBS needles from my carby and compare all three types togrther - but before I fork out the cash I just thought I'd check with the experience of the BonnevilleAmerica crew.
Like I stated, I'm happy enough and have had it this way for a year or so - just feel like I might start tinkering again for OPTIMUM.
Does it go like this...
790cc America Needle - more fuel - even more fuel
790cc America Needle - TBS needle - Thruxton needle
790cc America Needle - Thruxton - TBS
Anyone know?
Last edited by michael888; 04/20/2007 11:04 PM.
