running lean/popping-neede expert advice

[rocketray]

My bike sat for awhile--3 months--and the carbs set up--I took the bike to the local Honda shop in Mckinney Tx for a rebuild--picking it up today it pops badly on the decel after revving it up---the bike has the Viking headers and needles and has always run great--while it was down and I did get the headers ceramic coated ..? would the ceramic coating make the headers flow that much better to do a rejet?? of if rejetting up to what and which jets??

[98valk]

idle mixture screws are too lean. open them up 1/2 turn at a time until the major popping goes away. will never be 100% unless way too rich.

[big poppa pump]

When was the last time you checked your vacuum tubing? I had popping on decel back in 2013 when I first got the bike and I traced it to rotting vacuum caps.

[PharmBoy]

Also the gaskets between the heads and the intake manifolds may be leaking and causing a lean mixture because they were not changed. With the enging warm and at idle, spray propane fuel or starting fluid around each manifold/head connection. An increase in RPM will indicate a leaky gasket...Jim

[old2soon]

Look at the carb clamps. 18 of them NEED to be snug. IF yer mech wasn't a Valkyrie mech he/she could have not done or forgotten "things".  RIDE SAFE.

[salty1]

Time to desmog? ???

[Bigwolf]

Be sure to check the cut valves and the tubing connected to them.  The cut valves are there for the sole purpose of eliminating decel poping.  5 of the 6 were bad on my bike at 25k.  I think most people overlook these when trying to fix decel popping.  Pray that you don't have to replace any of them.  They are quite pricey.

[Roidfingers]

  CA, when you say idle mixture screw, is that the same as pilot screw? Also I'm only idleing at about 500 rpm, could this be an issue to with popping? doesn't pop at idle just at decal and mainly in lower gears.

[salty1]

Deceleration popping is a lean condition. Many suggestions have been made to minimize it. An idle setting shouldn't cause your problem. These beasts tend to pop some.

[Roidfingers]

So you adjust this with the idle mixture screw ? or is that the same as pilot screw? The "D" shaped one?

[98valk]

CA, when you say idle mixture screw, is that the same as pilot screw? Also I'm only idleing at about 500 rpm, could this be an issue to with popping? doesn't pop at idle just at decal and mainly in lower gears.

yes.
needs to idle 900-1000, any lower less oil pressure to cams and esp alt is not providing power to electrical system, its about 700-800 rpms its all battery.

[Challenger]

All good suggestions above, but just to throw another scenario out there. I have redone the carbs on two different Valks that came back from a Honda dealership after carb cleaning work with the same symptons as you describe. After removing the slow jets I found them to be plugged. It took about 15 to 20 minutes each with an injector tip cleaning tool to unplug them. Standard carb cleaning soak would not do it.That is why some folks just opt to replace them rather than clean them. Also both of these bikes needed choke (enriching) to start even at 65°. After cleaning they would both start at 45° with no choke. Without being super vigilant they might not have gotten them clean.

[The emperor has no clothes]

Be sure to check the cut valves and the tubing connected to them.  The cut valves are there for the sole purpose of eliminating decel poping.  5 of the 6 were bad on my bike at 25k.  I think most people overlook these when trying to fix decel popping.  Pray that you don't have to replace any of them.  They are quite pricey.

I don't have the decel popping, but I'm not familiar with the cut valves. What are those ?

[Roidfingers]

So, I adjust the normal idle with the big fat grey knob correct? then make an pilot screw adjustment of 1/4 turn on all carbs ? Help Please.

[longrider]

Pilot jets should be set at 2 1/4 turns open after the jet has been seated.  Then reset the idle to 900 to 1000

[Roidfingers]

So longrider.  Which turn. left or right seats them and then turn back the other way 2 1/4. Then adjust my idle?

[98valk]

righty tighty, lefty loosey.

set your idle first. then off. VERY LIGHTLY seat the idle mixture screws. with the viking pipes and stock 35 pilot jets 3 turns out will be about right. if one size larger PJ, then 2 1/2 out. start, warm up, short ride, reset your idle to 900 rpms.
I have viking pipes, air box mods, etc., and have done much tuning.

[Bigwolf]

Be sure to check the cut valves and the tubing connected to them.  The cut valves are there for the sole purpose of eliminating decel poping.  5 of the 6 were bad on my bike at 25k.  I think most people overlook these when trying to fix decel popping.  Pray that you don't have to replace any of them.  They are quite pricey.

I don't have the decel popping, but I'm not familiar with the cut valves. What are those ?

Air cut valves - Number 24 on this parts diagram.  http://www.hondapartshouse.com/oemparts/a/hon/50541208f870021c54bee64e/carburetor-components

The air cut valves shut off some of the air to the idle circuit when you let off the throttle.  This causes a rich idle mixture at decel  but returns to it's normal lean idle mixture when the engine vacuum returns to it's normal operating range.

Actually, this is the best price I have seen for these.  When I needed mine, the best price I could find was $78 each.

[Attic Rat]

Best Prices I have found
http://www.procaliber.com/oemparts/a/hon/5054120bf870021c54bee658/carburetor-components

[Bigwolf]

Best Prices I have found
http://www.procaliber.com/oemparts/a/hon/5054120bf870021c54bee658/carburetor-components

Thanks Bob
I had those guys in my parts bookmarks but my computer crashed so I am working from a tablet now.  No bookmarks.

[The emperor has no clothes]

Be sure to check the cut valves and the tubing connected to them.  The cut valves are there for the sole purpose of eliminating decel poping.  5 of the 6 were bad on my bike at 25k.  I think most people overlook these when trying to fix decel popping.  Pray that you don't have to replace any of them.  They are quite pricey.

I don't have the decel popping, but I'm not familiar with the cut valves. What are those ?

Air cut valves - Number 24 on this parts diagram.  http://www.hondapartshouse.com/oemparts/a/hon/50541208f870021c54bee64e/carburetor-components

The air cut valves shut off some of the air to the idle circuit when you let off the throttle.  This causes a rich idle mixture at decel  but returns to it's normal lean idle mixture when the engine vacuum returns to it's normal operating range.

Actually, this is the best price I have seen for these.  When I needed mine, the best price I could find was $78 each.

Thanks, never knew about those 

[Attic Rat]

I spend a lot of money  with those guys each month. most of the time it is 40% off with free freight and no taxes plus they go off true list not inflated list price like most dealers do

[Roidfingers]

Ok CA, so start the bike, and set my idle. Turn it off. Then close/seat/ screw by turning right till it barely touches. Then turn out/ left +- 3 complete rotations of the screw. Do all 6, then start and warm up and then reset idle. Correct?

[longrider]

Some may disagree here but I have seen first hand that it is be possible to run very rich if the pilots are opened too far. Fuel mileage drops dramatically.  So CA is right  with the Viking pipes it may be 3 turns but if you have an extreme raw fuel smell at idle you may want to trim them back 1/4 turn or more  as no two motors are the same.  And these settings are with 35 lows.  It would change if 38 lows are in there

[Roidfingers]

I have cobra 6 x 6 and no baffles. Stock carbs. So maybe just 2 3/4 turn to start. Also when you say turn you mean a complete rotation?

[rocketray]

thanx everybody for contributing to the thread----is it possible the jets weren't completely cleaned in the soaking solution?? but if they were slightly clogged with varnish it would have been popping BEFORE the rebuild right?-not just after--- So then back to all the vacum lines and all?Thanx again all--I have been riding  the wife's  Honda VTX1300R which is actually a relaxing low centered cruiser--it certainly slows a fella down compared to the Valk and her new Indian Cheiftain-good torque --great big fairing w/adjustable  windshield/Great Long travel suspension--the ride makes the Valk seem cheap-- but it just  doesn't have  the Valks power/scream and howl.....