The Davinci mod has nothing to do with the Thunderjet. As stated, the Thunderjet is an add on fuel circuit and would have nothing to do with the high idle problem. The high idle is being caused by excessive air most likely from misadjusted cables.
To answer the OP about the extra lines, the curled up line in the picture is a bowl overflow line that just runs overboard normally below engine.
If it won’t run without the enricher, you need to remove the bowl and intermediate jet and ensure it’s not clogged.

 

Ok...so the consensus thinks that it's most likely my throttle adj. I'm pretty sure the throttle plate is opening 90 degrees (WOT not my prob) it's difficult to see the stop plate. To me it looks like it does not fully close. Looks like it's open by a few mm. I'll try and adjust the play on that cable. I'll try and see if I can find which mod it is. I assumed that was an overflow line cause I jerked the bike while trying to adjust something and a good amount of fuel was discharged... is that normal? I mean it's hanging not too far from a hot exhaust pipe. Ka boom. My 1st and last ride. Also...I bought the bike on the cheap(so I thought 1000 bucks) non running and was mostly concerned whether or not the engine was locked up or siezed but considering it runs I'm good as far as that goes. Correct? Thanks for all the input. V

 

yep left out a word "to"
a source of concern on butterfly carbs is the butterfly shaft and the carb body. there is usually no bushing there to replace. one of the mods is to reduce shaft size, a reason why i mentioned checking for that modification.
once you start passing the 3k range, that thunderjet starts coming into play. all said and done, mikuni hsr42 would do nicely.
why put on a band-aide when stitches do better.
divide and conquer as the saying goes, remove the cables and see if you can get normal idle.

also of note that some air cleaners will block the bowl vent so s&s has an aux vent you can use. if the bowl goes +/- in pressure, will cause issues like excess fuel or starvation. should not be effecting your issue though.

 

Fuel leaking from drain is not normal. Sounds like it needs a carb rebuild and proper adjustment of cables.

 

Hmmm....well maybe I should get a rebuild kit for the carb and remove the mode. From the looks its original. Any thoughts on how great or not the modification is ? V
Or is that not possible....looks like the mod mills new ports in the carb. Ugh...

 

No need to remove the Thunderjet. If you don’t want to use it, you can just plug the jet with a toothpick. It’s under that knurled **** on top.

 

ok, you've got an S&S carb, most likely and E, with a thunderjet. the thunderjet is a great piece and once tuned in correctly does lots of good things
the Tjet is not your issue, make sure that the throttle plate is fully closed. take off the air cleaner, and look at the plate in the carb throat, operate the throttle and watch the plate open and close.
as long as that appears ok, now check your cable adjustment, there needs to be some free play, twist the throttle to all the way, WOT, and see if the throttle plate goes horizontal, thiss is all the way open,
let the trottle go and make sure that the plate closes and hits the idle speed adjument screw. if all that is good, amke sure that you dont have something binding the enrichner valve open, its iits own little fuel circuit as well.
you should probably remove the floatbowl and make sure everything is clean and clear and remove the slow jet an clean/clear it as well and re-install.
let us know.
m

 

Thanks Marcodarq...will do.
Yes SS super E. Well maybe I'll rebuild and keep the Tjet.
Any thoughts on the knockoff kits for 16 bucks. I mean they're brass and metal screws and springs.

 

you most likely wont need anything but a bowl gasket and maybe the accelerator pump kit. again with the ac off, twist the wick and see if there is a nice spray of fuel from the pump, if so, leave it aline and just open it up, clean the jets and passages, make not of the installed jet sizes and re-assemble......lots of times the bowl gasket can be used several times, they are pretty durable and if you are careful and a little razor blade, you can get it off clean and re-use it. if the pump shot sucks, there is a rebuild kit just for it alone, not the whole carb kit.
report back when done please.
m

 

Imho, the only thing that would result in that high of engine speed is a stuck or held open throttle. Remove the ac and look inside and see if the stbrottle is closed. If not, disconnect the throttle cable and see if it then closes.