Bike won't idle below 1700

Alright here's the scoop, carbs clean as a whistle, bench sinked, no air leaks anywhere, tested with propane torch, timming is set, advancer is cleaned and lubed, works fine, like title says bike will not idle below 1700,if I turn the idle below that, hear a small pop then bam shuts off, runs like a top otherwise? Only thing I never checked is valve clearance, not sure if this is related but will never start with e start, one two kicks and it goes, if it is the valve clearance can i buy valve shims at like a auto parts store? Please advise me this issue is got me perplexed, and pissed, thanks a lot. Nathan.

Do you have acces to the mixture screw? Some American models have them capped off if so you can just drill through the cap that's what I did

Yes there three turn out, I keep thinking that's the issue

I'm having the same high idle problem except mines around 4k. Are the diaphragms in your carbs good?

Yep pulled the carbs apart today, clean and no holes or tears

Most likely sounds like pilot jet or path is clogged. They are contained in the float bowl on your carbs. You can soak it in carb cleaner.

BTW: the 750 twins use 32 mm valve shims, they are hard to find.

Last night I pulled the carbs off for the millionth time, stripped them and boiled them, also I now know I'm running stock jets, 45 pilot, 125 main, I have pods and a two into one exhaust system, I would think that would be to lean, yet I'm showing signs of rich, plugs fouling every 100 miles, there black with soot! Anyway it still won't idle low without shutting off, I think it's my crappy eBay coils, the spark is weak, I did the coil mod, have all new 8mm wires, new 5k ohm caps, the spark is weak yellow looking, could that cause my issue? I should note battery is new, my reg, rec, are working properly and charging battery. I love this bike it's a dream on the highway but it scares me in town it will die at a busy intersection,

New 750 wrote: Last night I pulled the carbs off for the millionth time, stripped them and boiled them, also I now know I'm running stock jets, 45 pilot, 125 main, I have pods and a two into one exhaust system, I would think that would be to lean, yet I'm showing signs of rich, plugs fouling every 100 miles, there black with soot!,

are you sure it's not cooked on oil? These are known to have bad valve seals that let oil run down onto the plugs.

And yes, with pods that setup is too lean. I run 50 pilots on mine with stock airbox and pipes.

I don't know how a coil would know to run bad only at lower RPM's. You should check your battery in case the batt voltage is dropping since at lower revs the alternator output is too low to run the system and it runs off the battery.

Is the coil you have new or used?

Also: make sure that "coil mod" isn't killing you. If the electrical system voltage is dropping at lower revs it could be letting the relay open and that would instantly kill the ignition. I would hard wire the coil in as a test to make sure that relay isn't screwing you.

I tested the battery voltage while running in is def in spec, both at idle and at rev, it's a brand new coil from eBay, it was only $20, I thought it could be oil but here is why I suspect it isn't, I can wipe it right off with a rag so I assumed it was soot from being rich, number two I literally use no oil, I run 20/50 Mobil 1 synthetic and change it every 1500-2000 and never need to add in between. Every 100-250 miles bike won't start so I pull the plugs wipe off with a rag and she fires right up! I'll order 50 pilot jets, how far out should my mixture screw be? I'm at 3 out from lightly seated, thanks Nathan . oh could someone point me in the direction of who sells jets, I saw them her. www.dimecitycycles.com/vintage-cafe-race...-jet-50-004-012.html . Are these correct

Have you checked your valve adjustment yet. If not, Why?
Steve

How did you check for air leaks with a propane torch?

First off, check and adjust the valves as needed.

2nd, the bike won't run right with pods and a pipe with stock jetting. If the plugs are black and sooty that has nothing to do with the jetting, and everything to do with a running problem. Running a bike with stock jets and pods will cause the engine to run lean and hot, if it runs at all.

Propane and/or spraying crap on the outside of an engine is an unreliable way to check for air leaks. The high idle indicates the bike is most likely lean.

Poor carb vacuum sync can also cause the idle to be unsteady, as would a variety of other maintenance concerns. I'd go and check all the basics and work your way through all the maintenance tasks. You may fix the bike along the way, and worst case, you will know what the problem is not.