Choke partially stuck? The poor mileage saga

[Hyde]

Back again, just spitballing ideas on you guys since it's quite a ways below freezing here and I don't have a garage at the moment! Thought about selling the bike and moving to something fuel injected but I just love the feel and the sound

I read that partially stuck choke plates could cause some of these concerns, I've used the choke so I know it does move but I've never needed it to start the bike even around 25F.

I've been chasing some poor mileage and power concerns on my fat lady for a while now. I've been getting 20-25mpg at 70-80mph, lost a ton of power at elevation going over the Continental Divide, and the bike falls on its face at 95-100. Sound like it would be worth looking at the choke?

I'm also going to check and make sure the needles weren't shimmed by a previous owner. I pulled the carbs and re-sealed fuel tubes last year but dummy me didn't look at jet sizes while the carbs were out

Background, I have a Pingel petcock, dan-marc shutoff, R&M belly tank installed so I don't think fuel delivery should be the issue. It's smog deleted, I have the intake boots on correctly.

[The emperor has no clothes]

When you say you don't need the choke to start it at 25*, does that mean it will idle after starting ? I think you have something wrong with the carbs or air filter. I've been at high elevations with little loss of power. And I've been over 115 with ample left.

[sandy]

 partially stuck choke plates

These carbs don't have choke plates. Choke is the wrong term as well. Valks have fuel enrichment valves. You can see if the valves are working when you operate the lever and follow the cable to the carbs. Poor mileage has many reasons. You're right to check the needles for shims first.

[WintrSol]

partially stuck choke plates

These carbs don't have choke plates. Choke is the wrong term as well. Valks have fuel enrichment valves. You can see if the valves are working when you operate the lever and follow the cable to the carbs. Poor mileage has many reasons. You're right to check the needles for shims first.

On each set of carbs there is a bracket that slides when the lever is pushed to the 'choke' position, #20 on this: https://www.partzilla.com/catalog/honda/motorcycle/1998/gl1500ct-a-valkyrie-tourer/carburetor-assy. The cable from the lever moves one bracket, and a cable from it goes over to the other side to pull the bracket there. Those brackets pull the enrichment valve in each carb; they look like fairly large brass rivets. When the lever is pushed back to the full off position, those valves should slide back into the carb bodies, as the brackets slide to the off position.
If you remove cover plates #22 and #26, you should be able to see them operate, and the cable adjusters.

[Hyde]

When you say you don't need the choke to start it at 25*, does that mean it will idle after starting ? I think you have something wrong with the carbs or air filter. I've been at high elevations with little loss of power. And I've been over 115 with ample left.

No matter what temp it is I have to crack the throttle to start then it will idle fine as long as it's not super cold. Then I will bump the "choke" for a minute. Also air filter is good

I've had this bike over 120 (on a closed course of course) and the only change since then is significantly larger bags.
Now I can be less barely crack triple digits and my Harley buddy goes snickering past me. I've also had it over some pretty tall passes but last time she was a blubbering mess.

Also as far as the choke plates, duh I can't believe I didn't remember that, I've had the carbs off before! Thanks for jogging me outta that brain fart. Just trying to brainstorm things to check when the weather warms.

[Brian]

If you are not the original owner and having issues like this, I suggest you go back thru your carbs and restore them to the OEM set-up. You did not mention any modification to your exhaust system and do you know if the trigger wheel has been replaced? I do recommend you replace the jets and clean out/rebuild your pilot valve ports. Then after you have it back running, synchronize the carbs. Just my two cents.

[Hyde]

If you are not the original owner and having issues like this, I suggest you go back thru your carbs and restore them to the OEM set-up. You did not mention any modification to your exhaust system and do you know if the trigger wheel has been replaced? I do recommend you replace the jets and clean out/rebuild your pilot valve ports. Then after you have it back running, synchronize the carbs. Just my two cents.

Exhaust was stock when I got it, I did a glasspack mod. It got poor mileage with the stock exhaust as well. I did pill the timing cover and belt last year to check the timing wheel it is stock. I did do an ECT mod, that should not affect anything at cruising rpm from my understanding though

[The emperor has no clothes]

When you say you don't need the choke to start it at 25*, does that mean it will idle after starting ? I think you have something wrong with the carbs or air filter. I've been at high elevations with little loss of power. And I've been over 115 with ample left.

No matter what temp it is I have to crack the throttle to start then it will idle fine as long as it's not super cold. Then I will bump the "choke" for a minute. Also air filter is good

I've had this bike over 120 (on a closed course of course) and the only change since then is significantly larger bags.
Now I can be less barely crack triple digits and my Harley buddy goes snickering past me. I've also had it over some pretty tall passes but last time she was a blubbering mess.

Also as far as the choke plates, duh I can't believe I didn't remember that, I've had the carbs off before! Thanks for jogging me outta that brain fart. Just trying to brainstorm things to check when the weather warms.

Yours starts and runs completely different than both of mine. Neither likes ANY throttle as I start it. When it’s cold they both require some choke to idle. Being that your bike ran good before, I would suspect something with the carbs. What exactly I don’t know. I think I would start with removal , cleaning, and inspection of the various circuits. Something I haven’t dealt with but others have reported issues with is the air cut off valves.

[WintrSol]

Have you checked the plugs? Your symptoms (low mileage, poor performance at elevation) say rich. Are all 6 plugs covered in carbon, or just some?

[RWhitehouse]

These things aren't fuel sippers but 20mpg is definitely way below average for normal 75mph highway riding. low 30's seems to be more the average, maybe upper 30s if you really baby it. 100mph should be effortless as well, I've had mine up to about 130 with both bags packed to the brim.

If you're curious about the choke sticking, remove the two decorative covers on the carbs, one per side. There's three philips screws that hold it on, with it out of the way you can see the choke linkage and the choke plungers. Verify neither one of the sides are sticking and that the plungers are returning to fully seated (try to push each one in with a flat screwdriver, you shouldn't be able to move it). If anything is sticking, clean/lube it up. Not a bad idea to lube the cables as well.

Check if you have aftermarket needles. Pull the CV caps and take a look. Stock needle is non-adjustable and should have one (and only one) washer under it. If there's more washers, or the needle has an adjustable clip, remove the extras or try moving the clip one notch toward the flat end and see if things improve.

If that doesn't help, time to get into the carbs. Any number of things can cause a rich condition and subsequent poor MPG, too many to detail. I'd just go through and rebuild the lot of them, checking to see if a previous owner may have put bigger jets or an aftermarket needle in

[MarkT]

Fuel starving can cause the high speed cutout.  Though I would look at the plugs first to see what burn you're getting.  I have a belly tank (though plumbed as gravity feed), desmog, Pingel and a Dan-Marc.  Desmog and Pingel won't be the problem.  I had starvation issues that caused high speed cutout (though not THAT fast). Towing a Timeout camper to Morgantown.  You could have more than 1 problem like starvation at high demand with a too-rich condition.  The poor mileage, starting w/o choke, and problems going over the pass implies exacerbated too-rich, as it gets richer as you go higher. Though I concede most problems have one cause.  Anyway, check you don't have dips or rises in your fuel line in addition to the other fuel system checks mentioned.  A partially pinched tank vent hose can cause fuel starving both completely and at high demand only.  As well as the fuel filter R&M provides, isn't clogged.  And your pump isn't failing - that has failed for several friends I could mention - some suspect that's from heat.  I went to the larger 1/4" orifice Dan-Marc.   I also added a heat shield between the pump and the right side header pipes.