ECM

[bradbates]

I'm getting a lot of directions in which to look to correct my issue.  I think it's really something simple.  Let me bounce this off you folks.  I have a K&N air filter with the foam prefilter.  I got to thinking the K&N may have been restricting my air flow causing a rich mixture in the rpm range I hear the problem so, I pulled the foam pre filter last night, buttoned her up and went for a test ride.  Maybe slightly better but still not right.  I was researching K&N filters and their installation instructions say to remove the two sealing gaskets used with the original filter, one is on the air box side, then the filter and then another in the filter box lid.  I noticed last night my air box top has the rubber gasket in it.  I left it not knowing better.  I have noticed the air box lid takes some effort to get the screws started and I'll bet the bottom gasket is still in there too!  Could I be 180 degrees off and maybe the air box is not sealing properly and instead of rich I'm running lean?  Naw, that can't be it.  The only thing that could effect would be the filtration of the air being sucked in. 

[98valk]

only use an OEM filter.   check/re-tighten all airbox to carb connections and intake manifold to head bolts. New O-rings or old?   how old are plugs? resistant/ohm test each one. even new can be bad. (Had that on my DR once, 700 miles on plug and it went bad.) Test same for each plug wire. corrosion inside plug caps? too much dielectric grease inside plug caps which does not conduct electricity?   its not fuel related, missing, back firing etc., while running down the road is an ignition issue.

[Firefighter]

There you go, pull plug wires one at a time and see if you can isolate which one is your problem!

[bradbates]

I think I may have it figured out with the help of my new friend Attic Rat.  Waiting on the stock air filter to arrive.  It's quite possible I over oiled the K&N, maybe under oiled, who the hell knows!  I DO know that with the K&N installed the original air box gaskets are to be removed, the were not!  I talked with Bob last night and he said try it with the original air filter and see how it does.  He says some Valks, under no load and steady throttle burble some in the exhaust until you either decel or roll on some throttle.  He gave me another tip, why he does not know but, sometimes opening the pilot screw on #3 one full turn will make a difference and even things out.  None of the others, just #3.  No re-sunch, just open up #3.  I'll be interested to see if I need to try that and the results.  Bob says all in all I may be chasing ghosts.  This thing is new to me and I gotta quit comparing it to my '08 Goldwing i sold a couple month ago.  Just a matter of getting used to the new ride.  Nothing a LONG trip won't cure beginning with a buzz down to Tulsa to have The Attic Rat eyeball the old girl and get his hands on opinion.  Thank you each and every one for your replies to my ramblings.  There are a bunch of great tips in my thread that I will save for future reference.  Ride safe!

[dave011182]

He says some Valks, under no load and steady throttle burble some in the exhaust until you either decel or roll on some throttle. 

I haven't been on here in quite some time and don't post much when I am, but this is the exact same symptom I've noticed on my Valk since I got her a little over 6 years ago. Sounds a little sputtery to me almost anywhere between 2 and 3k, more noticeable in lower gears maintaining any speed in that rpm range, any change in throttle load up or down and it clears. Never a performance issue unless I let her sit too long(maybe 2 weeks), then she idles like crap and hesitates until warmed up and run. Stock exhaust, modified exhaust, tune up, carb sync and adjust, stock or K&N filter. Nothing has made any difference for me and I was just starting to research it again when I found this thread. I was getting ready to pull the carbs this winter and give them a full workup, but I guess that's not really necessary after reading all that you've done.

[bradbates]

I hear 'ya Brother!  I have a couple more things to try.  I've been working with Attic Rat and he says pull the K&N filter and put in a stock factory filter.  He says if that doesn't make any difference to turn the mixture screw on #3 carb out one full turn, #3 ONLY!  If neither of those things helps he says there are (for reasons unknown to him) some Valkyries that run like this.  Lower speed, constant throttle, no load on the engine they bubble and blurble.  If the above doesn't work I'm going to keep hunting and in your hunt, if you run across anything please share with me.  I just can't believe there's not some little something causing this issue, trick is finding it.

[98valk]

I hear 'ya Brother!  I have a couple more things to try.  I've been working with Attic Rat and he says pull the K&N filter and put in a stock factory filter.  He says if that doesn't make any difference to turn the mixture screw on #3 carb out one full turn, #3 ONLY!  If neither of those things helps he says there are (for reasons unknown to him) some Valkyries that run like this.  Lower speed, constant throttle, no load on the engine they bubble and blurble.  If the above doesn't work I'm going to keep hunting and in your hunt, if you run across anything please share with me.  I just can't believe there's not some little something causing this issue, trick is finding it.

also try running the front two carbs needles richer than the other four. two same size additional washers if OEM needles.  Marc from FactoryPro recommends this as a result of his dyno work.

[bradbates]

Yikes!  That's probably a bit beyond my current skill set.

[98valk]

Yikes!  That's probably a bit beyond my current skill set.

super easy to do. hardest part is getting the correct washers.

http://www.rattlebars.com/mtz/shims.html

[bradbates]

Hmm, I checked the link you gave me and I may try that after I install the stock air filter and see if it helps that midrange flat spot. It appears I can handle that. In the link it references a modified exhaust can cause the flat spot and I haven't a clue if my exhaust is modified or not as I don't have anything to compare it to but it makes sense. What doesn't make sense to me is putting washers in only the front two carbs rather than all of them.


Thank you.

[98valk]

Hmm, I checked the link you gave me and I may try that after I install the stock air filter and see if it helps that midrange flat spot. It appears I can handle that. In the link it references a modified exhaust can cause the flat spot and I haven't a clue if my exhaust is modified or not as I don't have anything to compare it to but it makes sense. What doesn't make sense to me is putting washers in only the front two carbs rather than all of them.


Thank you.

the front two get their fuel supply from the middle carbs, resulting in a slightly lower float level. lower level causes leaness, higher richness.  FactoryPro site has a tech article about carb tunning, worth the read. Most Honda carb floats are non-adjustable.

[bradbates]

I did not know that. I assumed the fuel ran down the fuel rail feeding each one individually. So you're saying one carb sucks off the next one upstream. I'll look up that article. Thank you.

[98valk]

I did not know that. I assumed the fuel ran down the fuel rail feeding each one individually. So you're saying one carb sucks off the next one upstream. I'll look up that article. Thank you.

middle and rear carbs, fuel supply is btwn them with a tee to feed each one the front ones are connected to the middle carbs.
with my air box mods the slight stumble/roughness whatever u want to call it, was more pronounced. once I richen only the front carbs needles it did run much better at all RPMs. now run FP kit with adjustable needles, front are still richer.

[bradbates]

That makes sense to me now, thank you.