Desmog now popping on decel

[Ecmech]

Have a 97 standard, just completed the desmog today using the kit from Red-eye. Before doing the desmog had no popping on decel, but on the first ride after the desmog, I now have a popping on decel on the right side. Is it a coincidence that it started after the desmog or do you think I induced a vacumn leak somewhere? Any help would be appreciated, Thanks

[Bighead]

Don't know but I thought the vaccum lines were removed during a de-smog.

[Ecmech]

Yes I removed all the Pair equipment and lines, just wondering if I need to check all my clamps and exhaust bolts  where I plugged the ports again for tightness? It almost seems like I have a miss now? Thanks for your response

[Hook#3287]

My first check would be the intake caps.

[Ecmech]

You are referring to the 4 plugs I installed in doing the desmog? I will check those first thing this morning and all other clamps, Thank You!

[The emperor has no clothes]

You are referring to the 4 plugs I installed in doing the desmog? I will check those first thing this morning and all other clamps, Thank You!

I think Hook is referring to the caps on the vacuum nipples (on the intake runners)

[Ecmech]

Thanks Meathead, just checked them and they all look like the original caps, small cracks in all of them, didn't notice until I pulled one off! Thanks, I'll replace them

[The emperor has no clothes]

Thanks Meathead, just checked them and they all look like the original caps, small cracks in all of them, didn't notice until I pulled one off! Thanks, I'll replace them

Might take a couple days to get them. But I highly recommend BonS's vacuum caps. Good quality stuff. 

[Hook#3287]

Thanks Meathead, just checked them and they all look like the original caps, small cracks in all of them, didn't notice until I pulled one off! Thanks, I'll replace them

You can make your own with some of the small vacuum hose you removed and some bolts stuffed in them.  That'll get you by for a week or forever.  I've got some I made & put on over 8-9 years ago.

[Ecmech]

Changed the vacuum caps and the hoses to the air cut off valves, at idle I'm still getting popping or a miss on the Right side! Could it be a spark plug wire issue or still think it's vacuum related?

[The emperor has no clothes]

Changed the vacuum caps and the hoses to the air cut off valves, at idle I'm still getting popping or a miss on the Right side! Could it be a spark plug wire issue or still think it's vacuum related?

How is it running on a ride ? Are you getting popping on decel ?

[Ecmech]

Yes, still getting the popping while riding after decel, not sure what to do next? Think it could be running lean in one of the cylinders?

[Hook#3287]

On the intake manifolds there are what's called "Pressure Boost Joints"


#10 here.
http://www.procaliber.com/oemparts/a/hon/506c2e5ff870023420a31aed/cylinder-head

One for each intake.  After de-smog you should have 5 capped and one with a hose to the petcock, if you still use the OEM one.

Is that what you have?

Have you check for spark at all plugs?

[Ecmech]

Yes I have 5 that have new caps, and I have not checked for spark at each plug, but I will do that next, Thanks for your help!

[Hook#3287]

Changed the vacuum caps and the hoses to the air cut off valves

I'm not familiar with Red-eye's kits, I've always left the chrome on and just plugged them.

What do you mean by "hoses to the air cut off valves"?

[Ecmech]

The hoses on the sides of the carbs that goes to the cutoff valves, I just checked spark on the right side cylinders, all is good there, so maybe the idle circuit is the problem? I'm guessing now

[Hook#3287]

Did you check the air box clamps?  Very easy to miss one that isn't set correctly.  I usually use a flashlight and look from one side to the other, very slowly checking that the rubber is not kinked somewhere.  You could also start the bike, let it idle and spray a little engine starter under the air box.  If the idle picks up, you know somethings wrong.

[Ecmech]

Thanks I will try that next, I looked at the pressure boost joints and snugged them up and started it up, the popping was a little less, I noticed that the air box clamps are mostly bottomed out, maybe the clamps are getting worn?

[Hook#3287]

You can over tighten the clamps and they will slip. 

You used a new hose for the petcock vacuum?

[Ecmech]

Yes I rebuilt the petcock and replaced the hose that goes to it last fall, I will check those clamps again, Thanks for your help with my issues, it is greatly appreciated!!

[The emperor has no clothes]

I think you are narrowing it down. When you check your air box boots use a small flashlight from the opposite side and get an up close look. I've got about a 1/4" gap on my clamps. If yours are almost touching there is probably something amiss. I don't think the clamps would stretch that much.

[Ecmech]

Thanks Meathead, I will check those clamps, maybe I have gotten carried away with how tight I'm getting them, do you think doing the Desmog has caused the Valkyrie to run differently, wouldn't I have popping with both sides if that was the case? Thanks again for your time

[The emperor has no clothes]

Thanks Meathead, I will check those clamps, maybe I have gotten carried away with how tight I'm getting them, do you think doing the Desmog has caused the Valkyrie to run differently, wouldn't I have popping with both sides if that was the case? Thanks again for your time

No, it should just fine with the desmog. I'm no expert by any means. But I think you've got a vacuum leak somewhere. Those rubber boots can be a pain the butt. Make sure your other clamps below the carbs are snugged up. They've been known to loosen up a lot on their own. I'm not familiar with the Redeye kit either. Did you plug up the hole in the air box bottom ?

[Ecmech]

Yes the Desmog kit came with a plug for the air box,I will check the security on it again, should I also check the gasket for where the exhaust was plugged, maybe I didn't get the Allen screws tight enough?Hopefully this is nothing more than a leak somewhere!

[Gavin_Sons]

Any time I mess with anything that has to do with the carbs I re sync.  I think a carb sync needs to be done.

[Ecmech]

Yes, I don't know if that has ever been done on this Valkyrie, I need to get a digi sync

[Kep]

I have a Digi-sync up in Logansport if you could make it up this way....plus a nice heated and cooled garage.

[Hook#3287]

I'm no expert by any means. But I think you've got a vacuum leak somewhere.

Neither am I, but I also feel it's vacuum related.

Yes, I don't know if that has ever been done on this Valkyrie, I need to get a digi sync

If you handled the carb bank with caution and didn't mess with the sync screws, I doubt that is your issue.  But, a sync is a good thing and the Digi-Sync is awesome.

I'm not sure this is related or not, but are you confident the air cut off tubes were not damaged on install?

, I noticed that the air box clamps are mostly bottomed out

I'm wondering if these are overtightened and one slipped?

[Ecmech]

I changed the lines on the air cut off valves , I will check them again for condition, as well as the clamps on the airbox, Thanks Kep, I might take u up on that, thanks to all the replies, this forum is awesome

[Kep]

Check my post on either the 1500 tech or General board about Indiana ride-in/tech day/lunch/BS

[clanky]

If I remember correctly one of the benefits of the "smog" system was to eliminate popping upon deceleration.  The "smog" system lets some air into the exhaust piping when decelerating to reduce/eliminate popping.
So popping after doing a de-smog sounds like the normal after effect.

[Fazer]

I did not see where anyone else suggested you check the intake boots where they cover the top of the carb.  They can get folded over when replacing the air box and are difficult to see.  I had a couple like that when I did my desmog.  You can easily check with a dentists mirror and flashlight.  Also, I had to remove the left side exhaust to get to one of the smog "buttons"--I did not do the kit desmog.  I bought 14mm freeze plugs and fabricated covers for the two lines under the bike.  I know that if the exhaust header is not snug, you can experience popping on decel.

[Harryc]

If I remember correctly one of the benefits of the "smog" system was to eliminate popping upon deceleration.  The "smog" system lets some air into the exhaust piping when decelerating to reduce/eliminate popping.
So popping after doing a de-smog sounds like the normal after effect.

Can anyone else confirm this? I was thinking about doing a desmog but if this is correct I will reconsider.

[Ricky-D]

The smog system was there to help insure the engine meets emission standards.

There is no direct benefit derived from removing a properly functioning smog system.

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[The emperor has no clothes]

If I remember correctly one of the benefits of the "smog" system was to eliminate popping upon deceleration.  The "smog" system lets some air into the exhaust piping when decelerating to reduce/eliminate popping.
So popping after doing a de-smog sounds like the normal after effect.

Can anyone else confirm this? I was thinking about doing a desmog but if this is correct I will reconsider.

Wasn't the case for me on 2 different bikes.

[Ecmech]

Thanks Fazer, I did check the boots at the top of the carbs and they look good, I suggested earlier that maybe I'm trying to get them too tight, the one question I still have is why I'm only getting popping on one side? Maybe the smog equipment was masking another problem? Right now at idle I'm still getting a pop from the Right side, it goes away when I ride at speed then comes back when I decel, but it almost sounds like a miss? Thanks for everyone's input, just added some Berrymans B-12 and took it for a ride, acceleration is great and so is the throttle response, so I guess I'm confused

[h13man]

On later VT1100 Shadows adjusting the air screws to 2 3/4 - 3 turns alleviated deaccel popping due to lean setting from the factory.

[Crackerborn]

See if the air cut hoses are cracked (the short hoses on the carbs). If they are original they could be leaking air and causing your pop.

[Ricky-D]

Depending on what you consider "popping" , it could simply be a result of your modified exhaust.  Also, I'd suggest to run some heavy doses of "Berrymans" thru the system since a slightly blocked slow speed orifice can cause "popping".  And finally, a system that is not properly synchronized will also pop a little. Gurgling, popping is all a matter of degree and understanding this, an internal combustion engine with an exhaust will always have some degree of popping/gurgling.

***

[crobii]

Hate to ask, but I didn't see anyone else bring it up....Did you go with new o-rings on the intakes? If you have a leak there, it will cause issues with one cylinder. You can try the starter fluid trick on each of those to track it down if that's the issue. And it goes without saying, but make sure you didn't leave one of those intake bolts loose.