?? One Time "Chunk" sound on freeway

[Texas Jimbo]

Recently had carb bank out to replace o rings fixing fuel leak.  Did Cobra Needles/springs Dynojet kit while carbs were off.

Runs good, but noticed on freeway yesterday that I had a one time "chunk" sound. 
Thought I hit something, but rear view mirror didn't show anything. 
Then thought tire, but they're good.
Checked for leaks, NONE
power was fine , ...

what the heck was that "chunk" sound/vibration? ??? ???

 

[Tfrank59]

Well you probably expect us to say not enough information, so I'll say it -- not enough information I have heard similar clunks from my bike, checked the rearview like you did, and kept going wondering what the heck just happened.  I think my conclusion was it was something in the road – at least that's what I choose to believe 

[Jess from VA]

Just a WAG, but a one time chunk should always make you consider that flap of rubber up under the front fender.  It may take higher speeds and bumps to catch the tire... at least until it comes off.

[Texas Jimbo]

 ??? there's a flap of rubber under the fender?

Hrm..  Guess I'll check that with a flashlight when I get home.

I HAD detailed the bike Saturday, so maybe I loosened it up when I was spraying.

Thanks for the idea.

[BF]

Actually, there's two of them....one on each side on the inside of the fender. 

[sandy]

ACTUALLY there are 4 of them. One in front of the fender mount and one to the rear of the mount, on both sides. They muffle harmonics in the metal fender.

[longrider]

What you have experienced is a momentary miss in the engine.  I haven't read about it for awhile but it happens to me once or twice a year.  We've never figured it out.  The motor cuts out for a split second and usually won't do again for some time.  Some think it may be a dirty kill switch, but personally think it static build up at the ICM.   Ride on, no worries.

Warren

[Hook#3287]

What you have experienced is a momentary miss in the engine.  I haven't read about it for awhile but it happens to me once or twice a year.  We've never figured it out.  The motor cuts out for a split second and usually won't do again for some time.  Some think it may be a dirty kill switch, but personally think it static build up at the ICM.   Ride on, no worries.

Warren

Warren's right, this has been discussed before and it happened to me once, way back in 2000.  One time only.

[doubletee]

This is the first time I've heard of others experiencing this. I've had it happen twice in the 12 years I've had my Valk. Glad to hear it's nothing to be concerned about, because it's very disconcerting to hear/feel it out on the road. Thanks for the info.     

[Tfrank59]

I have to admit, I'm a little surprised that with that description you guys are able to nail down what's going on.  Although a couple of you think it's chunks falling out of the fender well, some of the veterans believe it's this one-time event in the motor, but personally I just don't see how you can be so sure.   At any rate, it seems like it's not anything to be too concerned about – after all it's not frequent or recurring – and I've had it happen or at least I think I did to some degree.  Maybe it's one of those things in life that just takes care of itself – we know there aren't many of those! 

[longrider]

IF it is the engine miss as I suspect,  it will happen at random maybe even twice in short order (has happened to me) then not happen again for many months.  I've had it happen twice in one day.  Got my attention and I was worried like you.  It's been 6 months or more since mine has done it.  I just purchased a 2000 with 8700 miles on it.  It will be  my third valk.  125k on the first.  101 on the second.  We'll see if the third does it as well.

Warren

[pancho]

Out drive shafts are spring loaded to keep them seated in the pinion cup as they slide in the splines as the swing arm moves up and down. I believe that under certain torque, road and driving circumstances, the shaft hangs without being bottomed in the pinion cup, then when conditions change, the spring causes the shaft to reseat in the cup and you hear a "chunk"   At least that is what I think is happening with mine when I hear that random and infrequent clunk.

[Tfrank59]

Out drive shafts are spring loaded to keep them seated in the pinion cup as they slide in the splines as the swing arm moves up and down. I believe that under certain torque, road and driving circumstances, the shaft hangs without being bottomed in the pinion cup, then when conditions change, the spring causes the shaft to reseat in the cup and you hear a "chunk"   At least that is what I think is happening with mine when I hear that random and infrequent clunk.

Huh, that's a really good explanation which I think may account for a "random clunk" I have heard/felt on occasion as well.  It also makes me feel better because it's more or less benign

[Eric58701]

pancho I think you nailed it, I actually took my interstate out for the first time this year, I put on 20 some miles riding alone, then the wife joined me for a little road trip , when I was alone all was good, and when she was with I to experienced this clunk n chunk when I would hit the cracks in the road surface, it would chunk a clunk , I stopped to check it all out, though maybe it was the trunk coming loose or something, it was all tight found nothing loose, I was going to post up a question of hearing it here tonite, well now I don't have to,  poncho I think is rite, and just to relieve me some, as the more we both rode together the sound disappeared . all is good, now to just get it to idle better is so rich at idle