Bonneville America Forums Forums Technical Forums Performance Mods Carb Help Please

I have an '05 with those stupid little d-adjusters on the mixture screws. Can anyone tell me what size threads those needle screws have? They look like they are an 8mm fine thread but I really need to know. Thanks in advance ---

You can take them out with a pair of hemostats and cut a screwdriver slot in them and re-install. Problem solved. You can also flatten one side of a piece of brake line to make a D tool. As far as the thread, I never measured it. You can also get thumb adjustable mixture screws here.

If you were looking top repair the threads due to a boo boo can't help you at the moment I would have to go out and find the extra screws I have and measure the threads.

Yes, Thank YOU! -- that is exactly what I purchased but the threads are stripped an I will need to put in a helicoil for the ****** thing (or get an ebay used carb).

I have to ask...how did you manage to strip those threads?

If you stripped the threads buy bottoming it out then the seat is screwed too. You have to be very gental when closing those, the tip of the screw and the seat are very easily damaged.

I may not make any friends with this post but.... Mike's ad for those screws says "Straight from the Harley world".. if in fact those are HD thumbscrews there is a good chance the taper is different from ours. HD's have a single, larger carb feeding 2 cylinders, thus the difference in taper. I had HD screws in my carbs for awhile til I realized that they provided little to no adjustment. There was a thread or two about this many moons ago complete with pix and it ended with Brent at newspeedmaster.com making thumbscrews with the correct taper for our carbs.
Now, I know Mike (Racedweeb) at BellaCorse knows his stuff, and the "Straight from the Harley world" might just be wording in the ad, but I would check the taper of the needle end of the thumbscrews compared to the d-screws you remove from the carbs just to be sure. I'm just putting this out there as an FYI.. I'm not looking to step on anyone's toes. But I been there, and done dat.
Here's a pic.

[image][/image]

Brent's thumbscrew and stock screw on the left. HD thumbscrew on the right...

These could use a good cleaning but at $200 aren't such a bad deal...
http://cgi.ebay.com/ebaymotors/Triumph-A...#ht_4325wt_1930

13,000 isn't too many miles either, those carbs should go a while. Maybe Mike will see this and chime in to enlighten us as to weather they are actually HD or not. I remember that thread about the 2 different tapers I just cut slots in the OEM D head screws.