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Jre257
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« on: May 10, 2020, 08:52:34 AM » |
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Hello.I know that this topic is covered in a variety of areas in forum,but it is easier to ask due to my particular issyes.So u recently did a PAIR valve removal.All went well.And the bike popped on decel before and after.So my thoughts are: Air screw mixture set,( and where exactly is that screw? Can you adjust easily? Next I think I need to do a carb balance.I dont have a balance kit,I know you can make one.And I take it you need to balance all 6 at one time?Lastly,the pop in decel means the bike is too lean? Which means it is fuel lean? And you need to adjust the air screws to cut down on air? That has always been a little fuzzy.
Thank you!!
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da prez
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« Reply #1 on: May 10, 2020, 11:19:45 AM » |
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Go back to basics. Be sure the exhaust is properly tightened. Check all vacuum lines , better yet , replace them. Check the intake runners. Did the air box get properly installed. Do a shout out for someone in your area. There is a digisync near you. If you are not in witness protection , help is near.
da prez
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WintrSol
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« Reply #2 on: May 10, 2020, 01:09:18 PM » |
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Pop on decel is an indication of the engine going lean (too little fuel in the air). Since it was happening before the desmog, clearly the problem is not the result of your work. You could have failing air cut-off valves, which cut the air during high-vacuum operation (engine braking), leaking O-ring seals on the intake runners at the cylinder head end, cracks in the rubber boots between the runners and carbs, or, yes, the pilot screws (not air screws, BTW) could be set too lean, the pilot jets somewhat clogged, or the header seals leaking. There are vacuum lines to the cut-off valves that can crack and leak, too. These bikes are old enough that any, or all, of those things could be present.
The pilot screws are on the bottom of the carbs; if you use a mirror and bright light, you can see a little D-shaped brass head, inside a cast collar. Of course, you need a special to to fit them. They don't control the amount of air, per se, but the amount of enriched fuel/air mixture through the idle jets. Some of that mixture bypasses the throttle plates to provide enough fuel when the throttles are nearly closed. If the pilot jets that provide the fuel to this mixture are partially blocked, you will get a lean mix when the throttles are nearly closed.
Simplest thing to start is treat a tank or two with your favorite fuel system cleaner, like Berrymans B12, Seafoam, etc., which should clean up the jets.
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98 Honda Valkyrie GL1500CT Tourer
Photo of my FIL Jack, in honor of his WWII service
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rug_burn
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« Reply #3 on: May 10, 2020, 01:29:33 PM » |
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The same thing happened to me- and it was on cyls #3 and #4.
After a little investigation, I found I had some small holes and internal thinning on the two vacuum lines going to these cylinders. The popping was mainly on decel when there was high enough vacuum to suck in a lot of air, making it run lean, and misfire, until it built up enough unburned fuel in the muffler and backfired, fairly loudly.
This damage to the hoses seemed to have happened when I had some gas go bad, and I was using a lot of additives to try to avoid the inevitable: having to pull the carbs and clean and rebuild them... (which I eventually did)
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...insert hip saying here..
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Jess from VA
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« Reply #4 on: May 10, 2020, 01:44:09 PM » |
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After desmog, my bike backfired (not poped) on decel because the caps on the intake nipples failed (blown clear off and cracked).
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..
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« Reply #5 on: May 10, 2020, 02:44:43 PM » |
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9Ball
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« Reply #6 on: May 11, 2020, 03:40:45 PM » |
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After desmog, my bike backfired (not poped) on decel because the caps on the intake nipples failed (blown clear off and cracked).
I had that happen once...it woke me up! |
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VRCC #6897, Joined May, 2000
1999 Standard
2007 Rocket 3
2005 VTX 1300S
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Jess from VA
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« Reply #7 on: May 12, 2020, 03:05:06 AM » |
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After desmog, my bike backfired (not poped) on decel because the caps on the intake nipples failed (blown clear off and cracked).
I had that happen once...it woke me up! Yeah, on the way home from the last Asheville Inzane on the freeway, it also woke up all the nearby cagers, who were certain they were being fired upon. I had no idea what was causing it, only that if I avoided sudden throttle drops, the gunfire was greatly diminished. At 70+mph, it was a fair imitation of a .38/.357. |
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shadowsoftime
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« Reply #8 on: May 12, 2020, 06:27:59 AM » |
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replaced all 20 year old vacuum lines, no more decel popping.
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Jim in Idaho
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« Reply #9 on: May 13, 2020, 08:29:08 AM » |
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My bike was resolved COMPLETELY with desmog and new crush washers on the exhaust headers; so I'd go after a new set of copper crush washers for the exhaust mount.
FYI: Cobra 6into6
Jim in Idaho
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Jre257
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« Reply #10 on: May 15, 2020, 11:05:32 AM » |
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Thank you all of you! You have given me great direction I will check it out and get back to you
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