Idle problem hit "out of the blue."

[John Schmidt]

Was going to meet some other Valk folks today for lunch about 40 miles away, so cranked up the Valk to roll out about 10:45am. The old girl seemed a bit cranky when starting and kept dying on me as I backed out, acting sorta cold blooded without using a choke. As I rode down the street and shifted at low RPM as I approached a stop sign, about then it died again. Whoa....not normal. I went another 3-4 miles and it wanted to quit at every light or stop sign unless I kept the throttle slightly open. Otherwise it simply idled so low it would quit. I finally turned around and headed for home, if I hit the throttle real good it took off like a bandit, just would't idle.

When I got home I fiddled with the idle adjust but it had not effect. I finally got it to idle up some but if I held the throttle at a constant 3k for a few seconds and released it, the throttle snapped back as always but the rpm slowly dropped, and then only dropped to something well over 1k. I fiddled with the throttle cable adjustment at the grip but without any change so put it back where it was. About two months back I did some maint. that involved removing the tank and airbox. But, I've ridden it a number of times since and it ran fine, has me scratching my noggin. I have three one-way valves used in my cruise control, located between the intake runners and the vacuum box. I'm wondering if a bad one-way valve could cause such a problem. I hate jumping in and trying all sorts of remedies, but the darn thing so far hasn't given me any clues....other than suddenly it won't idle. 

[Daycruiser]

I'd guess a vacuum leak or ignition coil gone south or disconnected since you had the tank off you may have knocked something loose.

[Attic Rat]

John ck the drool tube at the T

[John Schmidt]

John ck the drool tube at the T

Did it, got a tea spoon at the most, doubt that's enough to create a problem. Relaxing today, will address the problem tomorrow, want to isolate the cruise vacuum reservoir and everything that goes to it. Easy stuff first.    Pretty sure it's not plugged slow jets, simply because when I move the throttle to 8-900rpm manually, it runs smooth as silk without choking. Plugged slows won't do that.

[Attic Rat]

John the T on the drool tube behind the alternator sometimes get disconnected causing a vacuum leak not the end where the plug is.

[John Schmidt]

John the T on the drool tube behind the alternator sometimes get disconnected causing a vacuum leak not the end where the plug is.

Oh my, I just reread your first suggestion.....brain fart!    I'll take a look and let you know.

[Firefighter]

Mine did that once and it turned out to be a bad ground between the battery and the frame, check battery voltage, make sure it's charging and then check for same voltage between battery positive and the frame. I ran a extra ground between battery ground and the frame and everything was good.

[John Schmidt]

I've checked for vacuum leaks, found none. Checked the one-way valves for the cruise control....are OK. Pulled plug wires one at a time, all drop the RPM as expected. Checked engine/frame ground....clean and solid. As of Sunday evening it still didn't want to run at idle unless I cranked the idle speed way up, and then when I let off the throttle the RPM didn't snap back as it should, just slowly drop. When it was dying due to slow idle, I could hold the RPM at about 800 and it ran smooth without choking so that didn't sound like jets to me. I had to leave it alone Monday due to other responsibilities, so this morning I decided to dig into it. I was ready to pull the tank and airbox and try to pin down the source, but something told me to start it and let it run. Soon as I hit the starter it took off, really fast idle so the next few minutes was spent bringing it down to just under 1k. I set the throttle cables at the grip on the same setting as before, and then held the throttle at 3k RPM for a few seconds. I let go and it dropped like normal. Try as I could, I could not get it to act up, it sat there and ran like it always has so I slapped on the helmet and went for a short ride. Runs great, just like before. When I got back I dumped in a can of B-12 just in case but this has me mystified, could it have been some bad gas that got into the system and after all my tinkering it just finally got burned through? I doubt that was the problem, otherwise it wouldn't have run right at highway speed even though it wouldn't idle. Has me spooked now, wondering if it's safe to take a ride for any distance. Over 13 yrs. and the bike has never let me down, I'm not use to this on this bike.

Any thoughts or ideas, love to hear them.

[Lyle Laun]

John:
I've had something similar happen about 1500 miles in to a ride. I put in a can of fuel cleaner and everything was fine the next day. Rode it another 2,000 miles trouble free. I figured something went through the gas.

Lyle...

[John Schmidt]

Lyle, I hope you're right, sure acted like it. Can't help but wonder why it ran great at highway speed when it wouldn't idle. Maybe the fuel flow at speed was able to overcome the junk....if that's what it was.

[Wewaman]

Mr. John,
 
As in tune as you are with your Valk and all things mechanical for that matter,  I "Believe" that you were not supposed to ride that day 

Tony (aka Wewaman)

[Crackerborn]

I had similar symptoms last year. I never did figure out what the cause was but when I drained the bowls, the problem went away. I was on one of the two unplanned rides to the Sunshine State at freeway speeds so if it was trash in the lines, it may have been sucked through and I never noticed. Northern AL at the end of July sitting on asphalt draining the carb bowls ...... yep, memories. Got the Lady back on the freeway and by the next gas stop she was once again idling properly.

[John Schmidt]

Mr. John,
 
As in tune as you are with your Valk and all things mechanical for that matter,  I "Believe" that you were not supposed to ride that day 

Tony (aka Wewaman)

Tony, I wouldn't be a bit surprised. The route I would have taken has a lot of construction going on, very rough, lots of fools cutting in/out. Lanes are changing back/forth while the construction continues, it's on SR 50 (aka Colonial Dr.) going east out of Orlando. I found it very trying even in the car a few weeks ago.

[Steve K (IA)]

I've checked for vacuum leaks, found none. Checked the one-way valves for the cruise control....are OK. Pulled plug wires one at a time, all drop the RPM as expected. Checked engine/frame ground....clean and solid. As of Sunday evening it still didn't want to run at idle unless I cranked the idle speed way up, and then when I let off the throttle the RPM didn't snap back as it should, just slowly drop. When it was dying due to slow idle, I could hold the RPM at about 800 and it ran smooth without choking so that didn't sound like jets to me. I had to leave it alone Monday due to other responsibilities, so this morning I decided to dig into it. I was ready to pull the tank and airbox and try to pin down the source, but something told me to start it and let it run. Soon as I hit the starter it took off, really fast idle so the next few minutes was spent bringing it down to just under 1k. I set the throttle cables at the grip on the same setting as before, and then held the throttle at 3k RPM for a few seconds. I let go and it dropped like normal. Try as I could, I could not get it to act up, it sat there and ran like it always has so I slapped on the helmet and went for a short ride. Runs great, just like before. When I got back I dumped in a can of B-12 just in case but this has me mystified, could it have been some bad gas that got into the system and after all my tinkering it just finally got burned through? I doubt that was the problem, otherwise it wouldn't have run right at highway speed even though it wouldn't idle. Has me spooked now, wondering if it's safe to take a ride for any distance. Over 13 yrs. and the bike has never let me down, I'm not use to this on this bike.

Any thoughts or ideas, love to hear them.

Do you have the OEM petcock?  That's how mine was running and it turned out to be a tear in the diaphragm. 

Found out when I was going to use my Digi Sync.  Trying to get a vacuum on the petcock vac line and no go.

[John Schmidt]

No Steve, have a manual Pingel with an inline filter and DanMarc elec. shutoff. Been trouble free for years, recently replaced the filter with the same type even though the old one was still good. I've put a bunch of miles on it since I did that so don't feel that had anything to do with the problem.

[Ricky-D]

It is good maintenance to occasionally spray a lubricant on all the carburetor linkage to keep everything working in good order. It certainly is needed due to the

complexity of all the connections, springs, adjustments and stops.

***

[Wewaman]

Mr. John,
 
As in tune as you are with your Valk and all things mechanical for that matter,  I "Believe" that you were not supposed to ride that day 

Tony (aka Wewaman)
[/quote]
Tony, I wouldn't be a bit surprised. The route I would have taken has a lot of construction going on, very rough, lots of fools cutting in/out. Lanes are changing back/forth while the construction continues, it's on SR 50 (aka Colonial Dr.) going east out of Orlando. I found it very trying even in the car a few weeks ago.
[/quote]


I drive a Tractor trailer on that road everyday delivering Duke Energy materials: IE ; Transformers, wire and the other things that make the lights work when we flip that little switch in our homes. 

Always idiots on the road.