High Speed Stall

[Ride Wild]

Hi Everyone. New member here from San Francisco!  Its a 99 Tourer with 24k on her. I bought her in LA and rode up to SF this weekend.  I know zip about mechanics and encountered two isses. Choke doesnt seem to have an effect (yes i pushed down all the way) so ended up hard starting her. The second and more life threatening was the stall at 75mph. Had no prior indication or warning had been smooth all the way 350 miles. Zipping along at 75 when there are two loud backfires and she cuts out..i clutch in and just managed to get off the busy SF highway without being hit. Sit for a while and then she started right up and i got her home. Ive tried to search for similar on the forum and didnt find anything. Im sure bike has sat but dealership told me the cleaned the carbs. Bike seems to idle and rev fine. Thanks for any help you may have on this!

[old2soon]

You didn't state how much fuel was in the tank. A stock fuel valve has a screen over the dip leg inside the tank. If this screen has gunch/mooky/kaka-ALL technical terms-on the screen it impedes fuel flow. Also our Valkyries-stock-have a gravity fuel feed. On the choke/enrichener cables and slides might need some lube. RIDE SAFE.

[hubcapsc]

old2soon might be onto something... if your petcock doesn't
flow right (a fairly common problem) you could get what you
described. They have petcock rebuild kits... they call them
"cover sets", honda part number: 16953-MBZ-B51

-Mike

[Daniel Meyer]

For the stalling, check petcock for proper function (do a vacuum leak-down test) and check the tank vent hose. May also pay to check the battery condition and connections.

On the choke, you can look down at the choke sliders just on top of the carbs and see if they move when you move the lever. That last 1/4 can be hard. If not moving you're not pushing the lever far enough or the cable is broken.

[Bagger John - #3785]

For the stalling, check petcock for proper function (do a vacuum leak-down test) and check the tank vent hose.

Had my Tourer's petcock go bad on a 75MPH, long uphill climb back in May while riding home from work. Leaky petcock diaphragm will eventually shut you down you every time at high speed, though you might get enough flow to operate the engine at 35-45MPH. (Luckily, I did.) Mine didn't "stall" - it progressively lost power if the throttle was held open. Upon returning to idle the bowls refilled and I was able to continue home via back roads.

Per the bolded item: Upon arriving home, the petcock vacuum line was removed from the #6 intake runner and checked with a hand-held vacuum pump/gauge.. Of course, the petcock wouldn't hold vacuum. A rebuild kit fixed things and I was back on my way.

[Marinakorp]

sounds like a clogged or malfunctioning gas tank vent tube (could be other things too as described)

next time... try leaving the gas cap open (vented) for a bit... if it doesn't come back, then that is the culprit.... don't use a full tank of gas obviously...

[old2soon]

Thanks for the input. So probably a fuel delivery issue vs carbs. With the gunshot backfire i was thinking carbs but as i mentioned i know jack. I will have my shop install the part mentioned by Mike. THANKS.

      If I might make a suggestion. Our M/Cs are getting older everyday and the mechanics appear-to me anywho-to be getting younger. AND most if not all of the maintenance on our Valkyries needs to be done RIGHT. You do NOT need a mechanical degree to do the work BUT you DO need common sense. A good repair manual some hand tools and the ability to read PLUS the archives in the tech section of this board PLUS the members of this board and getting over the initial fear of-I CAN'T do this cuz you CAN do this. AND do you REALLY want to make your mechanics Corvette payments??? RIDE SAFE.

[signart]

Y'all could be right, but the backfire at speed doesn't sound like fuel delivery problem to me. Sounds electrical or at least a vacuum leak.

[longrider]

I'm with signart on this one.  We all know when we run out on the main and switch to reserve the power loss is gradual as not all the carbs cut out at the exact same time unless prohutchinson didn't realize he had slowly been increasing throttle and she finally leaned out enough to backfire. 

prohutchinson,  did you have to wind her over for some time before she fired up?  It takes awhile for fuel to fill up the bowls when they are dry.  If it fired right up it should be electrical.

Check your battery cables and ground,  bank angle sensor or kill switch (did you happen to touch it as you were cruising along) as I'm leaning to electrical.

[hubcapsc]

kill switch

That's a good call... it is possible to rock the kill switch to
somewhere in the middle... not really on... not really off...

I did it once while doing some maintenance right before a ride,
didn't notice it.

I got about 20 miles down the road and my bike mysteriously
cut off...

-Mike

[Jess from VA]

Reaching out for the lever or mirror or throttle lock it is easy to hit the kill switch by accident, and on the freeway, when you rock it back on you get a big backfire.

[da prez]

Pro, there is help near you. Just ask. Dealers are expensive to use. Most work can be done with a little reading and common sense. If you can read, you should be able to work on your bike. The last bike I bought was dealer maintained and was a disaster. I am not saying all dealers are the same , but remember , mechanics work on f lat
 rate pay and use shortcuts.
             
                     D a prez

[Moonshot_1]

Few weeks ago I had the backfire. I did rock the kill switch and thats what caused it. Great big gun shot.

For you, this seems, at the moment, to be an anomaly. Maybe you hit the kill switch, maybe something along those lines happened (electrical).

In any event, I'd just keep riding it and wait till it does it again. Now that you are aware of it having done it, if it does it again you will likely be more aware of what you were doing or not doing immediately before.

Checking out the kill switch function wouldn't hurt either.

[Rio Wil]

There is a phenomena common to many Valks where about once a year or two the ignition will die completely for a quarter to one half second when tooling along at freeway speeds.  It is so fast that one blinks and says what the hell was that.....   Then it won't do it again for months or years. Mine has done it 4-5 times in 6 years. If this is a longer version of that phenomena then it might not happen again for months-years....

Yours sounds like an electrical failure, the petcock issue is similar to running out of fuel....happens kind of slowly compared to an electrical issue 

[Firefighter]

I agree with electrical, the spark was turned off and then on. I some how turned off my kill switch one time and when I turned it on I experienced a sonic boom. Not saying you turned it off only that it did stop sparking momentarily. Unless it stays off you will have to check everything related not knowing what is wrong unless you find something obvious.

The main fuse/start solenoid is know to burn up and cause trouble. Strange nobody is reporting that they have had the same problem. Let us know , good luck.

[gordonv]

There is a phenomena common to many Valks where about once a year or two the ignition will die completely for a quarter to one half second when tooling along at freeway speeds.  It is so fast that one blinks and says what the hell was that.....   Then it won't do it again for months or years. Mine has done it 4-5 times in 6 years. If this is a longer version of that phenomena then it might not happen again for months-years....

Yours sounds like an electrical failure, the petcock issue is similar to running out of fuel....happens kind of slowly compared to an electrical issue 

+1

You said nothing about the carbs loosing fuel and start to sputter to a stop, but an instant off. This is what happened to me once in the 6 months I road my IS for. If it doesn't happened enough to trace it to a problem, then don't worry about it. Yours is the 1st time I heard that a bike actually died and coasted to a stop (maybe the quick clutch work?). Most have the bike keep rolling on.

Besides that, Hello! Enjoy and start reading. Look up on hydro lock, and rear wheel maintenance. Don't be a stranger, or afraid to ask questions. Search is you friend.

[Rio Wil]

One other thing......there is a big green connector that plugs into the top of the starter relay, located under the right side cover. Sometimes that connector corrodes and does odd things.....worth taking a look at.

[Lyonardo]

Whenever I hear a huge backfire, I assume that the cylinders are actually full of excess, unburned fuel that finally goes off with a big bang.
If that assumption is correct, I'd go with the folks who say this is a spark problem as opposed to fuel supply.
I'd check everything in that circuit: from the spark plugs and wires, to the battery connections.

Did you notice if your indicator lights blinked out too?
A while ago, my bike went dead for a couple seconds on the freeway. I went into neutral to coast to a stop, but it restarted when I went back into gear and I kept going.
Once I got home I found that the bolt for my battery cable was slightly loose.

[Bighead]

I have had my 97 backfire at hwy speeds 4-5 times since new but it never died. Just a backfire and go. Never thought too much about it just kept riding.

[longrider]

Rio Will brought up the subject of a momentary miss at speed.  This has occurred to me on all 3 of the valks I have owned.  It is not unusual to have it happen two or three times a year.  I believe it may be caused by a static build up at the ecm or pickups. 

[chris1998]

Check the kick stand switch. It may be defective or just loose. Look under left side. The kick stand spring connects to a peg at the switch. It disables starting with stand down. Also, I would take engine up to the revs where it would be at 75mph. See if it stalls while revving stationary verses on road speed. It's a lot easier to diagnose a stationary bike!! 

Also, The bank sensor (Small black module, Under seat front of battery near seat lock mecanism) will disable ignition if bike is laid down.) It may just be loose.

Oh yeah. Also get a Honda manual for 97-03 valks. Just some ideas before you spend a lot.

Good Luck,
Chris