Going Crazy - Can't Stop Left Side Popping

[morrism1]

I've read the previous posts but I can't quite find what I need.

I have a 2000 Tourer with 16k miles. It used to run very well but it has developed a strong gasoline odor in the left side exhaust along with popping on decel and at low rpm. Everything I've read suggests that it is an intake side leak. The bike runs great when at higher RPM.

I replaced the rubber intake boots along with new o-rings. I installed the red Eye Desmog kit and a new air filter. I turned the idle down to about 600 (not sure why it was high), new copper crush washers on the left side, and new NGK plugs. The plug on cylinder #4 had a bit of oil on the thread but otherwise looked normal.

I ran a can of Berryman B12 through the tank and then re-filled it with fresh, ethanol-free gas. As far as I can tell all of the carb adjustments are original. All six exhaust outlets are hot.

The gas exhaust odor is much lower new as is the popping but the popping is still there. I small squirt of starting fluid on the intakes boots speeds up the rpm but the two clamps are as tight as possible.

My next step was to install new idle jets. I have no experience with carb syncing or air cut-off vales so I'm nervous about messing with those.

Can anyone help me out here?

[Valker]

Can’t help with the rest, but Valk idle speed should be 900 .

[Chrisj CMA]

Can’t help with the rest, but Valk idle speed should be 900 .

Yep idle 900-1000 may sound high because of six cylinders. But even 1000 is lower than most bikes.

[Jess from VA]

And it does not even charge at 900.

Could this be a poor airbox reinstall issue?

[Rollerman Dan]

Had the same issue on my 2001 IS after rebuilding carbs. FYI if carbs were find before this its probably not them.
I found a vacuum or vent tube/ plug  for desmogged version, had come off the bottom of front left carb. Causing the popping or backfire on that side. Reinstalled and all was well.

Hope info helps.

[agrady1995]

Had same issue with my IS. New intake boots too. Ended up with a SS hose clamp on the upper clamp location (carb output to boot) and that did the trick.

[Jersey]

You can try a Smoke Test (not sure what others call it).  Get a Propane tourch, the normal kind you use with basic plumbing.  After the bike is started turn on the propane and run the tip around all of the connection points on the bike where air can leak in.  The idea is the propane will get sucked in and cause the RPMs to change.  This is one way of finding leaks.  Take your time if you do this.

Hope that helps.

Jersey

[morrism1]

I used starter fluid with the thin red nozzle that comes on spray cans. The RPMs go a bit higher when I spray the new inlet boots but I have both clamps as tight as they will go. 

[Valker]

I used starter fluid with the thin red nozzle that comes on spray cans. The RPMs go a bit higher when I spray the new inlet boots but I have both clamps as tight as they will go. 

Make sure a piece of one isn't folded under with the clamp totally missing it.

[Gregory Scott 16248]

Get a small inspection mirror and check the back sides of the intake boots. Sounds like you have a rolled end of the boot not seating correctly. If your RPM'S go up using starting fluid or propane, that's where your leak is. Just because the clamp is as tight as it will go doesn't mean it's sealed.

I got these to reach around the back side of the intake boots, mini pick 90 deg. hook and use a mirror. Cheap and works good.
Harbor Freight, Mini Pick And Hook Set,  https://www.harborfreight.com/mini-pick-and-hook-set-63697.html?_br_psugg_q=pick+set

[rug_burn]

   That advice from Greg Scott, above is good, I find mirrors indespensible dealing with those clamps.
   Another thing that causes that popping is a crack or hole in those vacuum lines roing to the nipples on the back of the intake tubes.     I had holes in mine from either bad gas or one of the many gas additives I tried to cure another problem.