This is new... Surging

[lucky_1_chris]

On my way to work this morning the bike started surging a little bit at lights. After exiting the freeway, it hung at 1500 for a bit before returning to idle, then at the next light it started surging up to 13-1400 for a few seconds then it'd return to normal idle, and idle fine til I stopped at the next light. No popping.

Any ideas? Vac leak?

Edit: It's never done this til this morning. I got the bike in late Feb., so this may be the coldest I've ridden it in. Maybe the colder air is exaggerating a symptom I just haven't noticed before.

[olddog1946]

my vote would be Vacuum leak..

[Patrick]

How are the throttle cables ??

[Ricky-D]

Yep, first thing would be to lube the throttle cables and then spray the linkage with ample amounts of lubricating spray.

Need to eliminate any possibility of a sticking throttle assembly or sticky parts.

***

[lucky_1_chris]

my vote would be Vacuum leak..

Hope that's all it is. Is there anything else that could cause it?

[lucky_1_chris]

How are the throttle cables ??

Plenty of play in the sleeve. Snaps back quickly. Can't feel any hangups. I'll do the recommendation in the post above this one tonight to rule them out.

[Earl in Pensacola]

In-as-much-as your cables "snap back" and you can feel no hang-ups and you still have surging, then go with the "olddogs" suggestion--look for a vacuum leak!

[Ricky-D]

Although the ability of the throttle to snap back can be an indication of workability, I want to add that there is more to it than just that!

The linkages under the carburetor rails, where the springs and connections are all located also need lubrication periodically. Usually a spray lubricant generously applied is all that is needed.

I think when the motor starts over-running, like you describe it can sometimes be from a single carburetor not fully getting to "idle position".

I am not discounting the possibility of a vacuum leak. The only reason I mentioned doing a lubrication was that the over-running was reported as an intermittent thing and I feel a vacuum leak would cause a constant over-running of the motor at idle.

Over-running at idle and the failure of the motor to quickly get back to idle after closing the throttle can usually be attributed to a synchronization problem.

I'm not taking a hard line on any of this and simply am trying to suggest a line of action with the simplest and easiest things to do first.

I think looking for vacuum leaks is also one of the first things to do and should not be dismissed out of hand, which I am not doing.

***

[lucky_1_chris]

Although the ability of the throttle to snap back can be an indication of workability, I want to add that there is more to it than just that!

The linkages under the carburetor rails, where the springs and connections are all located also need lubrication periodically. Usually a spray lubricant generously applied is all that is needed.

I think when the motor starts over-running, like you describe it can sometimes be from a single carburetor not fully getting to "idle position".

I am not discounting the possibility of a vacuum leak. The only reason I mentioned doing a lubrication was that the over-running was reported as an intermittent thing and I feel a vacuum leak would cause a constant over-running of the motor at idle.

Over-running at idle and the failure of the motor to quickly get back to idle after closing the throttle can usually be attributed to a synchronization problem.

I'm not taking a hard line on any of this and simply am trying to suggest a line of action with the simplest and easiest things to do first.

I think looking for vacuum leaks is also one of the first things to do and should not be dismissed out of hand, which I am not doing.

***

My mind went to vacuum leak first, but I wanted to get an idea of what else may cause this problem. It has never held a perfect idle, but it's not surged like this (3-400 RPM) since I've owned it. When I got to work this morning I left it running while I went inside to open the ramp door, and when I came back out it started surging again for a few seconds before I got back on it. Cracked the throttle a few times after it returned to normal idle and it acted like normal. Something's up, and I'll look into all possibilities. I hope it's something simple and that I'm not experiencing the beginning of carb problems.

[Farther]

Look at removing excess play in the throttle cables too.

[Ricky-D]

Was it idling enough for the fan to come on?

Hot can cause some funny stuff.

***

[lucky_1_chris]

Was it idling enough for the fan to come on?

Hot can cause some funny stuff.

***

Not yet, but by the time I putted it to my parking spot on the dock it'd come on.

EDIT: It wasn't hot when it was surging at the stoplights, either.

[lucky_1_chris]

Look at removing excess play in the throttle cables too.

It's just enough play to jiggle the sleeve back and forth a little bit, nothing excessive.

[Grandpot]

Spray some carb cleaner or ether on the vacuum lines and air intake runners.  If the RPM changes, you found a vacuum leak.

[Ricky-D]

Look at removing excess play in the throttle cables too.

It's just enough play to jiggle the sleeve back and forth a little bit, nothing excessive.

That's good!  You need some play to allow it not to bind when turning the bars right to lock.

That is the way to adjust the cables also. At the lock position to the right.

***

[Challenger]

Pull the vac line off #6 carb and see if there is fuel in it. a pin hole in the petcock diaphram can let gas into the vac line.   

[lucky_1_chris]

Pull the vac line off #6 carb and see if there is fuel in it. a pin hole in the petcock diaphram can let gas into the vac line.   

Hadn't thought of that. Recently rebuilt the petcock...it's possible I damaged it maybe.

[Chiefy]

I've had funky gas cause that.  Rule out iffy gas first.

Check that your choke linkage at the carbs aren't sticky, bent, or something else.  Been there, done that.   The fastest way to see if the choke is causing this is to reach in and push on the linkage.  If it slows down, you've isolated the problem.

[lucky_1_chris]

What's the black box behind the ignition switch?

Just fired it up to head home from work, and I can feel air blowing from this box. Dunno if thats good, bad, or what... Is this part of the pair system? I'll investigate further when I get home.

[YoungPUP]

Check to make sure that the hoses going from it to the airbox are connected.

[Chiefy]

What's the black box behind the ignition switch?

Just fired it up to head home from work, and I can feel air blowing from this box. Dunno if thats good, bad, or what... Is this part of the pair system? I'll investigate further when I get home.

It's the storage tank for the crankcase breather.  I'm not sure exactly how it works.  However, at some point it must (??) be putting air/fumes back into the airbox.  So if you feel pressure, you might have a disconnected hose, which I suppose would cause a vacuum leak to the airbox.

[lucky_1_chris]

What's the black box behind the ignition switch?

Just fired it up to head home from work, and I can feel air blowing from this box. Dunno if thats good, bad, or what... Is this part of the pair system? I'll investigate further when I get home.

It's the storage tank for the crankcase breather.  I'm not sure exactly how it works.  However, at some point it must (??) be putting air/fumes back into the airbox.  So if you feel pressure, you might have a disconnected hose, which I suppose would cause a vacuum leak to the airbox.

Everything is connected, there are no open spots. Both lines are connected to the bottom of the air box. Maybe the air wasn't coming from that box, can't be sure, but it was coming from that area. I didn't feel any air coming from that area when I got home... I'll check again in the morning when it's cold like it was earlier. Dunno. I'll have a little more time and daylight then.

Snooping around I did notice a pretty strong gas smell coming from the front right of the motor, behind the pod. I pulled the pod off and got a flashlight to look for leaks. The vacuum cap on the front right intake was wet with gas. It was cracked and hard as a rock. May not be all of my problem, but there's a definite vacuum leak there  . I replaced it with some AutoZone caps, but I'll order the OEM caps tomorrow. The other 2 were cracked, too, so I replaced them, but they were holding cuz I got a little hiss when I pulled them off.

[Ricky-D]

Has your Valkyrie been desmogged?

***

[lucky_1_chris]

Well, I thought that maybe the bad vac plug solved the problem til I got to work. No surging at lights, but the rpm's did jump a little when I put it on the sidestand, and dropped when I picked it up. From 1000 to 1100, then back down once it picked it up. Still have the gas smell from the front right side behind the pod. No smell from the left side.

It has not been desmogged.

[Chiefy]

Well, I thought that maybe the bad vac plug solved the problem til I got to work. No surging at lights, but the rpm's did jump a little when I put it on the sidestand, and dropped when I picked it up. From 1000 to 1100, then back down once it picked it up. Still have the gas smell from the front right side behind the pod. No smell from the left side.

It has not been desmogged.

I sure don't know what to tell you.  But...... I have extra running lights I installed on the bike.  When I turn them on or off, the rpms change by 100.  You may want to look at things like a loose connector making your headlight, or other lights go in and out.   Might sound crazy, but it IS easy enough to check.  Hmmmmm maybe your fan is cutting in and out, and you didn't notice it when you left because the engine was cold?

[lucky_1_chris]

Well, I thought that maybe the bad vac plug solved the problem til I got to work. No surging at lights, but the rpm's did jump a little when I put it on the sidestand, and dropped when I picked it up. From 1000 to 1100, then back down once it picked it up. Still have the gas smell from the front right side behind the pod. No smell from the left side.

It has not been desmogged.

I sure don't know what to tell you.  But...... I have extra running lights I installed on the bike.  When I turn them on or off, the rpms change by 100.  You may want to look at things like a loose connector making your headlight, or other lights go in and out.   Might sound crazy, but it IS easy enough to check.  Hmmmmm maybe your fan is cutting in and out, and you didn't notice it when you left because the engine was cold?

It may have always done this... I was paying close attention to it this morning and was hyper aware of every little sound it made. I'll go through everything above this weekend. Don't know what the gas smell is... Looked for a leak last night and found nothing but the cracked plug soaked in gas. No other leak or sign of gas. It didn't hang up or surge at all on the way to work this morning. I heard some popping under the tank last night on the way home, and no sign of that this morning, either.

[Chiefy]

Well, I thought that maybe the bad vac plug solved the problem til I got to work. No surging at lights, but the rpm's did jump a little when I put it on the sidestand, and dropped when I picked it up. From 1000 to 1100, then back down once it picked it up. Still have the gas smell from the front right side behind the pod. No smell from the left side.

It has not been desmogged.

I sure don't know what to tell you.  But...... I have extra running lights I installed on the bike.  When I turn them on or off, the rpms change by 100.  You may want to look at things like a loose connector making your headlight, or other lights go in and out.   Might sound crazy, but it IS easy enough to check.  Hmmmmm maybe your fan is cutting in and out, and you didn't notice it when you left because the engine was cold?

It may have always done this... I was paying close attention to it this morning and was hyper aware of every little sound it made. I'll go through everything above this weekend. Don't know what the gas smell is... Looked for a leak last night and found nothing but the cracked plug soaked in gas. No other leak or sign of gas. It didn't hang up or surge at all on the way to work this morning. I heard some popping under the tank last night on the way home, and no sign of that this morning, either.

Well, my moto is "keep it simple."  The 100 rpm difference between the side stand and pulling it up could be something as simple as a sluggish throttle cable being disturbed as you wrestle the bike around.

[lucky_1_chris]

Well, I thought that maybe the bad vac plug solved the problem til I got to work. No surging at lights, but the rpm's did jump a little when I put it on the sidestand, and dropped when I picked it up. From 1000 to 1100, then back down once it picked it up. Still have the gas smell from the front right side behind the pod. No smell from the left side.

It has not been desmogged.

I sure don't know what to tell you.  But...... I have extra running lights I installed on the bike.  When I turn them on or off, the rpms change by 100.  You may want to look at things like a loose connector making your headlight, or other lights go in and out.   Might sound crazy, but it IS easy enough to check.  Hmmmmm maybe your fan is cutting in and out, and you didn't notice it when you left because the engine was cold?

It may have always done this... I was paying close attention to it this morning and was hyper aware of every little sound it made. I'll go through everything above this weekend. Don't know what the gas smell is... Looked for a leak last night and found nothing but the cracked plug soaked in gas. No other leak or sign of gas. It didn't hang up or surge at all on the way to work this morning. I heard some popping under the tank last night on the way home, and no sign of that this morning, either.

Well, my moto is "keep it simple."  The 100 rpm difference between the side stand and pulling it up could be something as simple as a sluggish throttle cable being disturbed as you wrestle the bike around.

True... I've got an aftermarket brake light and I sometimes notice the rpm's drop a bit when I squeeze the brake. It's entirely possible that paranoia is making me make a mountain out of a mole hill over the slight difference in rpm this morning...   It did run better this morning than it did yesterday morning and last night. I've only put 30 miles on it since I noticed the surging. Prolly need to ride it around some more to get a better picture.

I am going to thoroughly check the cables, linkage, etc., and after seeing how bad those vac caps actually are it's prolly a good idea to go ahead have a good look at the rest of the vac lines. Also need to find out what's causing the gas smell. It could be residual from the vac cap leaking.

[Chiefy]

Sometimes the petcock can leak out the bottom, and it's on the right side, just not near the front, worth a peek.

[YoungPUP]

Check the band clamps for the carbs and airbox, as well as look for staining around the bottom of the chrome intake tubes at the Cyl. Head.

[Challenger]

Check the fuel rails between the carbs for your gas smell, o-rings get old and will leak fuel, It will run down on the inside and lead you to believe it is the carb leaking.  YMMV.

[lucky_1_chris]

Sometimes the petcock can leak out the bottom, and it's on the right side, just not near the front, worth a peek.

No leaks from the petcock.

[lucky_1_chris]

Check the band clamps for the carbs and airbox, as well as look for staining around the bottom of the chrome intake tubes at the Cyl. Head.

I changed the intake o-rings in September due to some leaks. Dunno why I didn't check/replace those vac caps then.

[lucky_1_chris]

Check the fuel rails between the carbs for your gas smell, o-rings get old and will leak fuel, It will run down on the inside and lead you to believe it is the carb leaking.  YMMV.

What's the size of these o-rings? Can they be changed with the carbs on the bike? If I can't get these locally I'll wait to pull the air box til I have some in hand. Don't wanna do it twice, and don't wanna put it back together if I know they're leaking. The Valk is my daily transportation so i can't really  tear it down and leave it waiting for parts. If i can get them at Napa I'll go ahead and look today. The gas smell is coming from somewhere...

[lucky_1_chris]

Put some miles on the bike yesterday, and experienced zero surging. For now I'll assume that the surging problem was the cracked vac cap. It was nowhere near as cold yesterday as it was when the problem began, so I'll keep an eye on it. Still need to find where the gas smell is coming from, though. Is it possible I'm smelling the vent, and not an actual leak?

[salty1]

Get your parts from Rich - better than OEM. He has the vacuum caps, hoses, etc. You might want to consider installing one his desmog kits too. I think Challenger could be right on the fuel rail(s) being the gas smell source. Rich also has those O-rings. His website is shown below:
http://redeye.ecrater.com/

[lucky_1_chris]

Answered my own question about whether the carbs have to come out to change those o-rings. Hope I don't find any leaks...

[Valkpilot]

Put some miles on the bike yesterday, and experienced zero surging. For now I'll assume that the surging problem was the cracked vac cap. It was nowhere near as cold yesterday as it was when the problem began, so I'll keep an eye on it. Still need to find where the gas smell is coming from, though. Is it possible I'm smelling the vent, and not an actual leak?

Chris, when did you last drain the Dragon Drool?  It's the drain line on the  bottom right side of the bike that has the plug in it.

When mine start smelling gassy, that's usually the resolution.

[lucky_1_chris]

Put some miles on the bike yesterday, and experienced zero surging. For now I'll assume that the surging problem was the cracked vac cap. It was nowhere near as cold yesterday as it was when the problem began, so I'll keep an eye on it. Still need to find where the gas smell is coming from, though. Is it possible I'm smelling the vent, and not an actual leak?

Chris, when did you last drain the Dragon Drool?  It's the drain line on the  bottom right side of the bike that has the plug in it.

When mine start smelling gassy, that's usually the resolution.

I drained it at the last oil change, early October maybe 2k ago. I will drain it again before I go any further to rule it out. Would never have occurred to me...

Saturday after next my brother and a friend of mine are gonna pull the tank and airbox and look hard for leaks. Gonna swap vac lines, carb drain hoses, and sync the carbs at a minimum, and maybe pull the carbs to fix leaks if we find any. 4 of six drain hoses are cracked, vac plugs were cracked, I can only imagine what the rest of the rubber under there might look like.

Are you going to the WP next weekend? If I'm able to make it maybe the guys there get a whiff and see if they think the smell is normal or if it's something to worry about. I tend to be a little paranoid side...   I'd like to hear some other opinions.

[Ricky-D]

I think a lot of the reaction that you formulate ought to relate to the totality of the smell.

Like for instance if the gasoline smells considerably strong and persistent that would be a real concern and need immediate attention.

While on the other hand if the gasoline smell is just occasionally sensed and is wiffy like when you pass a gas station at times, well, then that is a different thing.

I on occasion get a gasoline smell and attribute it to the gas cap and seal which is probably not perfect but there has never been an instance where gasoline has escaped past the cap. So I don't worry about it!

How you approach this dilemma should have input from what you sense is the problem.

If you cannot see any gasoline dripping or leaking, the problem is seemingly, not big time serious, and should not encompass any large mechanical foray.

***