Feels like its starving for gas.

[DavRed]

Got on the Valk today after a 2 month period of time of not riding. I keep it on a battery tender. So the battery was strong. Took a while to crank up. I just figured that might be because the fuel bowls had dried out. But once she started it seemed fine. Once I started riding I noticed it seemed like it was starving for fuel. I could apply the gas a little. But when I gave it medium throttle. It just bogged down and had no power. Full throttle was the same. I went ahead and rode it up to the auto parts store and added a half of bottle of STP Carb cleaner. Then went to fill it up with new gas. It had about a half tank already. I rode it around for aver an hour. No change. Any Ideas?

Things I tried while I was riding was turning the gas to the off position. Yup she ran out of gas in about a mile or so. Tried both on and reserve. No change.

Thanks in advance.

[Toledo Mark]

Check the vent tube?  Maybe a spider crawled up and made a web?

[DavRed]

How would one go about testing that?

Never mind that question. I pulled it off from the rear of the tank and was able to blow through it with no problem...
I also hooked a hose up to the tank and blew through it with the cap closed and Open. Hmmm starting to think its petcock related...

[custom1]

A couple things to check for the petcock. It may not be getting enough vacuum to hold it open the whole way.

Look at the vacuum line that goes from it to the #6 carb. Check for cracks.

If you have a mighty vac or some way the apply vacuum to that line (with a gauge) and see if it holds vacuum or leaks down. The petcock may need a new diaphragm inside.

[Fla. Jim]

You might try this product. Sure helped me with my carb ill's after sitting a spell. you can read about my trevails here.

PS As an aside after cleaning 15 years of crud out I went from 34 mpg average to 40 mpg. The last tank was 41+ around town....Never thought i would join the 40mpg club.
 
http://www.valkyrieforum.com/bbs/index.php/topic,45784.0.html
                                           And VRCC And Members

[John U.]

DavRed, will the bike idle smoothly? Will it run better with the choke on? Usually, non-use of a Valk for  more than a few weeks, sometimes less, will cause problems with slow jets. Even though it initially started and seemed fine, crap from "ethanol enriched" gas can clog things up. You did the right thing adding some carb cleaner.
I like Techron, which is fairly strong, some use Berrymans which is even stronger. Give whatever you use some time to work. If the problems don't improve it's time to clean or replace your slow jets.

Open the carb bowl drain screws one at a time to be sure you have fuel flow to all the carbs. You could have one or more stuck float valves, or a clogged petcock screen.
On the other hand, if it idles and starts well then the starvation problem could well be the petcock as mentioned.

[Patrick]

From your post it appears you have a fuel delivery issue which can be a defective #6 vacuum line or petcock diaphragm.. The classic symptom of plugged low jets is poor running below 3K and good running above..

[DavRed]

Thanks for all the suggestions guys. I will check some more tomorrow morning. I did not get a chance to look at the #6 vacuum line. Yes it seems to idle just the same as it always has. and ticking the throttle seems the same. It is only under a load when it stumbles...

[DavRed]

Today I got the full tank of gas off the Valk.
I have a hand vacume pump. When I squeeze it with the petcock opens and gas flows for just a bit. The vacume does not stay. So fuel stops flowing quickly. I was gona drain it with the vacume pump with the fuel line open. I don't have that much hand strength to constantly pump the vacume pump 6.7 gallons of gas.  
2 Questions...
1: Is it normal for the petcock to close quickly and let the vacume bleed down?
2: What is the best was to open the petcock with out vacume? So I can drain the tank.

Thanks

[custom1]

The vacuum bleeding off means there is a hole in the diaphragm labeled #3 in the diagram below. If you are sure your hand pump is not leaking down, it should hold the vacuum. I can't think of an easy way to get it to stay open so you can drain it. Maybe someone else has a trick I am not aware of. Messy way would be to just remove the petcock. If you can get some gas out then stand the tank on it's nose the gas should be lower than the petcock opening. If your cap seal isn't sealing good it will come out there though.

If it is dripping gas from the vent hole that means the other diaphragm (#2) is bad also. If you are going to rebuild it you get both diaphragms in the cover set.

[DavRed]

Thanks,
I guess that is good news anyway. I have a new petcock on it way.

By the way. There is no smoking in my back yard....

Glad I live in the middle of the desert...

[sugerbear]

set the tank on a table syphon from the fill hole into a container on the ground.....

[DavRed]

Got the new petcock installed and all put back together.  Now the petcock holds a vacume.
So I was hopefull. After putting fresh gas in and taking it for a little ride. Still running bad. Full throttle its just bogging down. I pulled the plugs thinking that the starving of gas might have done something to them.
Here is a pic ot them.
The 3 on the right came from the right bank and the 3 on the left came from the left bank.

I plan of getting new puggs tomorrow.

Not sure why the 3 on each side look so differant.

[Valkpilot]

Got the new petcock installed and all put back together.  Now the petcock holds a vacume.
So I was hopefull. After putting fresh gas in and taking it for a little ride. Still running bad. Full throttle its just bogging down. I pulled the plugs thinking that the starving of gas might have done something to them.
Here is a pic ot them.
The 3 on the right came from the right bank and the 3 on the left came from the left bank.

I plan of getting new puggs tomorrow.

Not sure why the 3 on each side look so differant.

A failing petcock can cause uneven gas flow to the carbs.  They might have been so fouled because of this that they're still in that condition.

I've been through the same thing, and if I recall it was the left bank that fouled.  New plugs were the final step in the repair.

[sugerbear]

are BOTH sides of the choke turning all the way off?
looks like the three black ones are too rich.

[Gryphon Rider]

I wish I had read this thread earlier.  The symptom of idling fine but instantly stumbling when you twist the throttle is NOT a petcock issue, although it sounds like your petcock needed attention anyway.  This sounds very much like a carburetion issue to me, but since I haven't had this problem, I can't get more specific than that.  When I searched "stumbling" in this board, I came up with the following which most closely matches your problem:

http://www.valkyrieforum.com/bbs/index.php/topic,7595.0.html
Problem:
Now the bike runs fine up to about 1/2 to 2/3 throttle, but beyond that it stumbles, and at WOT it actually backfires.  I have been over it thoroughly looking for leaks and found and fixed a few things.  Made some progress on the stumble, but it is still there, and the backfiring is actually getting worse.
Solution:
Well, after doing everything else I finally pulled the mains jets on the sputtering side.  As it turns out I had 2 mains partially clogged.  Even though I had cleaned them with carb cleaner and blew them out with air, I hadn't actually inspected them before installation.  With a magnifying glass I could see some crap plugging the jets.
I tried to clean them out with a sewing needle (those holes are small) and dumped a bottle of Techron in the tank.  Running (almost) like new now!  Getting better every time I ride.

[DavRed]

I wish I had read this thread earlier.  The symptom of idling fine but instantly stumbling when you twist the throttle is NOT a petcock issue, although it sounds like your petcock needed attention anyway.  This sounds very much like a carburetion issue to me, but since I haven't had this problem, I can't get more specific than that.  When I searched "stumbling" in this board, I came up with the following which most closely matches your problem:

http://www.valkyrieforum.com/bbs/index.php/topic,7595.0.html
Problem:
Now the bike runs fine up to about 1/2 to 2/3 throttle, but beyond that it stumbles, and at WOT it actually backfires.  I have been over it thoroughly looking for leaks and found and fixed a few things.  Made some progress on the stumble, but it is still there, and the backfiring is actually getting worse.
Solution:
Well, after doing everything else I finally pulled the mains jets on the sputtering side.  As it turns out I had 2 mains partially clogged.  Even though I had cleaned them with carb cleaner and blew them out with air, I hadn't actually inspected them before installation.  With a magnifying glass I could see some crap plugging the jets.
I tried to clean them out with a sewing needle (those holes are small) and dumped a bottle of Techron in the tank.  Running (almost) like new now!  Getting better every time I ride.

Thanks,
Gryphon Rider
I replaced the plugs tonight and got the same problem. Now my question is. Do I have to remove the carburetors to clean this main jet? I am not sure I am willing to take that on if so.

I am looking at the manual on page 5-12 and it looks like they have to be removed and taken apart.

[Ricky-D]

It's easy enough to remove the intake risers to gain access to the carburetors.

Dropping the float bowls will give access to the jets.

Have to be careful in many ways to avoid problems that can crop up quickly.

***

[DavRed]

I am starting to think that this is not gas related at all. At about 3000 RPM it starts missing and the missing gets worse as I open the throttle. Keep in mind this is happening on the kick stand in the shop.
Sorta seems like it is spark related. ECM maybe... Any way to test that guy?

[Ricky-D]

Well that will explain the inconsistent look of the plugs.  Left bank to right bank.

***

[DavRed]

Thanks for all your help guys.
BigBF is gona take it on, from here.

Dont want to do any harm running it, with it missing and such....

Thanks Bill.

[salty1]

DavRed be sure and let us know what you find out that's causing your bike to run so poorly.

[BigBF]

Thanks for all your help guys.
BigBF is gona take it on, from here.

Dont want to do any harm running it, with it missing and such....

Thanks Bill.

No problem... See ya sometimes first week of Oct.
BigBF