That may be it GalvTex. If the vented gas cap is made to allow air in to prevent a tank vacuum, it had to have been positive pressure. When I loosen the cap the first time, it may have been air blowing out. Then that is the question, What causes high positive fuel tank pressure ? I need to check TC's. Thanks all. Bob

 

I've had EITMS disabled.
But, my bike since I've had it ( 1 year) does a kinda strange thing. When coming to a stop, I'm usually in second with the clutch pulled in. The bike will be at normal idle, but when the bike stops moving with the clutch pulled, the idle always surges up a couple hundred rpm's, then ramps back down to idle. Is that normal >

 

My 20 Sport Glide does that at stops just a little. Always has done it, I pay no attention to it, the bike runs great, now at 25.000 miles.

 

Hey CoolBreeze, found # 7 valve, fuel. I couldn't pull air thru it at the front of the rear where hose # 19 exits. Unhooked hose # 18 at the top of # 7, and can draw air thru the valve at exit of hose # 19. I hook to hose # 18 (at the end where it had hooked to # 7 valve) that runs to the fuel tank, and cannot draw air from the fuel tank. Should I be able to draw air from the fuel tank at hose # 18 ?

 

hey rcpbob....... I have 2023 fatboy and had that idle surging issue since new.. brought it back to
dealer 3 times, complaining that it can't be right. Was told repeatedly that it's normal for newer harleys.
Posted somewhere on this forum and had several replies saying it's normal, and is a safety feature to
prevent stalling at slow speeds.
I think you can get rid of it with a tuner, at least I would hope so.

 

I have a Stage 1 tune, still have the SE PST, don't know how to remove the idle surge at stopping. Bob

 

One problem solved, kinda' long explanation to follow. l think I've found the problem of idle surging up and down (super low 100 rpm to 1800 rpm), with lots of engine knocking. A year ago when I brought the bike, it already had SE Ventilator Air Cleaner installed. So I thought I'd take the Air Cleaner apart and see if anything was wrong. Well there was a problem, Screamin' Eagle AC instructions say to remove the stock induction module support bracket (see attach). It had not been removed on the initial install, so I remove the bracket. It now idles normally, throttles up and down without knocking and trying to die. Thanks to all who gave advice.
I will have to see if the gas tank over pressure happens again. It has a vented gas cap that I believe allows air into the gas tank, which it seems to do. Can anyone check that out ?
The hose the ends up in front of the rear tire, down low near the swing arm pivot point, I think is where the overflow of gas drains, when you over fill the gas tank. If this is blocked some where, would that allow over pressure to build up as engine heat soaks the gas tank ? Any ideas ?
Again, thanks for all your help everyone. Ride On ! Bob