After our 2021 WCC run this past weekend I now fully believe that the whole idle circuit needs to be cleaned before you can call it clean. Before the cruise I had removed the idle jets and used carb cleaner and a wire to clean them off and I put them back in. The car was running okay but it seemed like it was still a little rough. I had asked for and received advice on cleaning the whole circuit but I've been so dang busy I hadn't a chance to do the whole process.
During the WCC I was getting a soft backfire on deceleration. I called it "chuffing" because the backfiring seemed to be very soft and not like the backfire that set my air filter on fire several years ago. Anyway, to help stop the "chuffing" I just put the car in neutral during the long downhill sections and drove like normal during the level parts. I was quite disappointed in myself for not handling it before the event.
I have no transport jobs this week so I have plenty of time to get things done. I have concrete to remove, a fence/gate to demo, a load of rocks to rake up from my house and take to my daughter's apartment, replace the kitchen faucet, change out the pool lights, a few repairs I need some trades people over here to get done, and lastly some things need to be done with the Speedster. I need to clean the whole idle circuit, set the valves, change the oil, order some Cocomats, and get the car detailed as I've let it sit for too long with the cover off of it.
The first thing I did today was clean the whole idle circuit. I removed the air cleaners and filters. I took off the velocity stacks and the bottom plate. I took out the mains, the idle jets, and the idle mixture screws. I cleaned all of the parts with some carburetor cleaner. I used thin/stiff wire to make sure there was nothing sticking inside the mains and the idle jets. I used carb cleaner on the idle circuit using the included flexible house to spray cleaner into all of the openings. I let it sit for a minute and then I blew air into all of the openings as well, including the thin brass rods coming out of the top of the carbs. Once I was satisfied the whole circuit was clean I put it all back together. What a difference that made. I will no longer consider the "circuit" clean until and unless I do what I just did today.
Even with the JayCee idle jet holders (IJH) on my Webers it is a little difficult to get the idle jets out so I modified some tools to make it easier. I took the correct size allen wrench for the IJH and cut it short enough to fit in them and not hit the side of the engine bay. The allen wrench needed further modification so I took a Dremel and put most of the shaft on a diet by grinding out the portion of the key that doesn't go in the end of the IJH. If you need a little more leverage to tighten it up you can slip an extended socket over the end of the key to get some grip on it. Just don't crank on them too much, it isn't necessary. I also took a stubby flat blade screwdriver and cut off a significant portion of the handle and epoxied the blade back in the handle. The cut down stubby screwdriver made it easier to count the turns while backing out the idle mixture screws after seating them upon install. I couldn't see the IMSs at the back of the carbs so I just felt for the correct position of the blade while backing each one out.