fuel help

[Swamp Thang]

Hi everyone. This is the very first post ever for me on this forum. I have a 97 standard valk. I absolutely love the bike. I have been from coast to coast on it. I tell everyone this is the best bike I have ever put my a$$ on. I'm not sure yet how to post pics but at some point I will.

I really need some help. Last year while on a trip to yellowstone national park with my father this happened. When I hit the higher elevations it was like someone turned the choke on. Come to find out on the way out of the mountains it quit. It ran fine most of the way home. But since it got much worse. If I am driving below 40 mph it never happens but if I am on the super slabs it now ALWAYS happens. I have gotten to some points where it just quits altogether. So I took the bike to a honda dealer. They stated the carbs needed rebuilt. I had that done. After a couple thousand bucks imagine my surprise when it did not fix the problem. It is hard to explain when it does not do it every time to a mechanic. I am at my wits end at this point.

Should I just start changing out things like the petcock, all throttle linkage, and all of the choke linkage? After rebuilding the carbs I just don't know what else to do. The pipes are completely black and my friends say when we are on the highway when I put the fuel to it I get a huge black plume behind the bike. Any suggestions?


Jay

[Swamp Thang]

Thanks for the info but I have not only done this I carry spare plugs with me on trips and change them often. It is becoming a pain. I have not had to change plugs anywhere near the amount I had to before the carb rebuild. To give you a better understanding it acts as though you are running out of gas but as stated if you were to ride it you would understand it is being choked out. Just to give you another bit of information I have the 5 gal tank and while on the trip to yellowstone there were points where I only got 90 miles on a tank. And one time while in Wyoming I got 60 miles and had to fill. This is driving me nuts.

[Gryphon Rider]

So you've learned the first lesson of Valkyrie troubleshooting; you have a better chance of properly fixing or maintaining your Valkyrie by reading and posting to the VRCC tech forum and shoptalk pages than by having your dealer do it.

The problem that is most easily fixed that matches your symptoms is a kinked or blocked fuel tank vent line (hose).  Had you lifted your tank off the frame before your troubles started?  If so, when you re-seated the tank you may have kinked the vent hose, which doesn't allow air to enter the tank at the rate you use fuel, thus creating a vacuum in the tank and preventing fuel flow.  To test this theory, put a spare key in your gas cap, but don't open the cap.  Get the bike up to speed until the bike starts to sputter, then turn the gas cap key, allowing air to enter.  If the bike quickly recovers, the tank vent is the problem and is easily fixed by removing the vent hose kink.

If that doesn't work, the next likely culprit is the vacuum-operated part of the fuel valve.  There is either a leak in the vacuum hose to the fuel valve, or the vacuum diaphragm in the fuel valve has a tear in it.  In either case, engine vacuum can only provide enough negative pressure to hold the valve open part way, so at higher speeds or in the mountains when you are trying to use more fuel, the carburetors are starved and the bike sputters.  See my post linked here:
http://www.valkyrieforum.com/bbs/index.php/topic,37577.0.html

If both of these check out fine, the next thing I would suspect would be the ignition module, which could be checked by swapping modules with a local Valkyrie rider and going for a test run.  I have no experience with a bad module, so others may chime in about the likelihood of that being the problem.

[Patrick]

How long have you had this monster ??  Do you know the history of this thing ?? I'd like to know what has been done to it before you got it..
Did it start running this rich immediately or did it sneak up on you or has it done it since you got it ??  Has the air filter just been serviced ?? 
You may also have more than one problem.. Which petcock does it have and have any modifications been made to it ??  Do you know if any ignition changes have been made ??
Whenever I hear that the carburetors have recently been cleaned,, I don't pay too much attention since they are not cleaned correctly many times..

[sugerbear]

where are you located, could be someone close to help.

[Swamp Thang]

So thankful I found this board! I am loving this information and I do appreciate it. All will be looked into. Thank you! All of this makes sense. I have worked on many cars. But with the bike I always felt like I wanted a "professional" to do it. I recently lost my personal mechanic. My sister took him halfway across the country. Ugh! Yea she is married to a motorcycle mechanic and they moved 2k miles away. He just recently told me to look at the fuel valve.

To answer your question yes I have had the tank off several times. I installed a CB unit and ran the wires under the tank. It was off again as the CB unit got wet and failed. Then it was off a third time to re-install the CB unit after being fixed. And then off to rebuild the carbs. Any one of those could have kinked something.

[Swamp Thang]

I'm in Elkhart Indiana. I have had the bike for 4 years and well over 20k miles. Never had one problem and the bike gets serviced regularly. This started as soon as I hit Yellowstone and caught me offguard. Has not ran good since. I did not know much history before the buy but bought it from a reputable dealer. Maybe I should go back and ask for more details. I wonder if they know anything years later. And since it started every time we service it the problem actually gets worse. I have made no alterations myself since the buy other than adding a CB. And now having the carbs redone. But those were completely rebuilt by a certified mechanic.

[Swamp Thang]

How do I add a pic?

[Blackduck]

By the clouds of black it is too rich, guess the plugs had plenty of dry black soot.
Too much fuel or not enough air.
Air filter was mentioned earlier, stock or K&N? Last time serviced? Though the dealer should have checked that while attacking the carbs
Hook the #6 vacuum line off and check for fuel in the line, the one going to the petcock.
The next nasty thought is a bad needle and seat allowing a carb to flood.
Don't believe your American bikes have the foam pad in the intake tract, if it had it maybe coming off and blocking the intake.
Does not take much to restrict the standard intake.
Cheers Steve

[Gryphon Rider]

How do I add a pic?

You need to upload the picture to an image hosting sight or other internet location, then link to it using the picture icon when you post your message.  Many of us use photostash or justpics through this site.  Read this:
http://www.valkyrieforum.com/bbs/index.php/topic,856.0.html

[Chrisj CMA]

Its easy to confirm if its a vent problem.  Just run it with the gas cap open (not a full tank) if the situation improves its a venting issue, if it doesnt improve its not.  I think you said its a 97.  If the vacuum lines havent been changed do that.  If it still has a problem, I can almost guarantee its the petcock.

[Blackduck]

The only other thing I could think of and  have never heard of it related to Valk would be a restricted exhaust.
Cheers Steve

[BradValk48237]

Ditto, petcock...

They get a small/tiny hole to start and then can take a while to get big enough to make it so the bike wont run at all..... you get the same symptoms at speed.. will run fine at lower speeds and then act up on the highway.... 

Took me 2 issues to go to full manual......

Brad

[Swamp Thang]

I love it. Ya'll are a vast wealth of knowledge! Thank you!

[whitestroke]

Is the tank clean.  Next time its off turn it over and shake all the gas out.  A clean trashcan lid makes a good catch basin.  I found plenty of crap to clog screen in the tank.

[R J]

 
I'd say without seeing the bike it is an air filter problem.   Most dealers techs wouldn't even look at the filter during a carb rebuild.  The rebuild pays enough to not need extra $$$$ to look at the filter.

[Westsider]

Im going to remove my previous post's on your problem Swamp...Hopfully Valkpilot will chimme in on his exact same situation he had as yours,,, with a quick and EASY fix,,,  Paul...We both learned something today from you...Thanks..


Well I see its the same as GryphonRider,,,sorry again.... Thanks Gryphon Rider...

Thanks everybody.. Valkyries rule..Have a great weekend ride safe....Paul.

It sounds like the oem petcock strikes again,,,another plus side for a pingle to me.

[Valkpilot]

Im going to remove my previous post's on your problem Swamp...Hopfully Valkpilot will chimme in on his exact same situation he had as yours,,, with a quick and EASY fix,,,  Paul...We both learned something today from you...Thanks..


Well I see its the same as GryphonRider,,,sorry again.... Thanks Gryphon Rider...

Thanks everybody.. Valkyries rule..Have a great weekend ride safe....Paul.

I agree that you quite possibly have a petcock problem. 

I've personally experienced some plugs rich, some lean, black smoke, backfiring, and outright refusal to run.  All accompanied by lousy fuel mileage. 

Daniel Meyer explains how the petcock can cause all that in this thread: http://www.valkyrieforum.com/bbs/index.php/topic,27755.msg252626.html#msg252626

[Ricky-D]

Riding from a lower elevation up to a higher elevation will always make a motor want to run more richly.

Having work done on the carburetors by a "certified" mechanic is not a guarantee of correctness.

Attempting to assess a problem without knowing all the particulars is destined for failure.

Can you identify what jets are in the carburetors?

Have you stock exhaust on the bike?

Do you run top tier gasoline in the bike?

Is the bike desmogged?

***

[olddog1946]

I'm thinking a completely plugged up air filter, even a poorly done carb rebuild would have not made things worse each time the bike is run.  I may be way off here, but do the simple stuff first.

[Thunderbolt]

Air filter would be my guess.  Dirty if original filter, too much oil if k&n. 

[Regis]

everybody here has great info , tank vent sounds like a good clue but so does all the other info . All  I can say is that I went to Yellowstone this year from Indiana and got the best fuel mileage in Yellowstone that I ever got . may have been the higher elevation but i got 48+ on 1 days ride .  6 degree trigger wheel and all stock carbs with cobra EXHAUST , and desmogged .
.  keep lookin you'll find it .

[Swamp Thang]

I haven't been online lately but all of this information is fantastic. I'm sure by using it as a roadmap I will find the problem. At the age of 48 and back finishing my college degree I haven't had much time to continue reading this post but I guarantee you when I find the problem it will be posted here for all to see. I will be working on the bike this weekend and next. The air cleaner is a K&N and brand new. It is the onlly filter I use in my cycles as well as my off road jeep. We are going to remove the tank and flush as well as intall a new petcock just for giggles. While I have the tank off we arew going to check out the ventline. I may do as described and run it a little and then open the lid to see if the starving is cured by air. (great advice!) You guys rock!

[salty1]

Hey there Swamp! Just recently did YNP and the only place I noticed the bike laboring (running rich) a little was at the top of Beartooth Pass (10947 ft). I agree with a lot what's been posted here to resolve the rich running condition of your bike. My vote is for bad air filter. Did the "stealer" synchronize the carbs when he was finished? The latter shouldn't be the major cause of your problem. I wonder how many turns they put on your pilot screws? Keep us posted.  

[fon1961]

my two cents, kinked vent hose or petcock...