18 MPG.... Yuck.. 1985 Vt1100

[Dartmech]

Ok my fuel problems have been confirmed. At first I thought the gas gauge was bad on my 1985 VT1100. I saw it drop drastically after 35 miles and when I got home with 46 miles on the trip (Most all highway) I was able to put 2.55 gallons in. There is definitely something wrong here.
She's got no pull, I'm wide open and 75 is all she'll do. I figured with a 1100 it would pull strong no matter what so now I'm thinking there's a mix problem somewhere. Its just me on the bike (190lbs), I bought it with a Jardine exhaust already installed. I'm wondering if it wasn't jetted or something? But that would make me think lean.
Any help here guys would be awesome. I'm trying to avoid a shop visit.

[still.southern]

Does it bog on the last quarter of the throttle?

Also what do the spark plugs look like?

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[Dartmech]

I haven't had a chance to pull the plugs. It runs great around town, but ya it kinda bogs when full throttle. It sometimes feels like when I let off slowly to decelerate she'll get an extra boost.

[still.southern]

Originally Posted by Dartmech

I haven't had a chance to pull the plugs. It runs great around town, but ya it kinda bogs when full throttle. It sometimes feels like when I let off slowly to decelerate she'll get an extra boost.

Assuming this is a "new to you" bike and not a problem that has just shown up, I'd actually think it's running too rich. I accidentally jetted mine to rich and I got the exact same symptoms, including half of the proper gas mileage. Do the pipes have baffles? You might be jetted for straight pipes.

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[Dartmech]

Ya I just got the bike, and I knew after the first few highway rides that something was wrong. Today I was able to confirm anything. It has to be rich I would think, filters and other items clogging would just make it lean out which would not suck the fuel down. Dang I guess i'll have to get somebody to check the carbs. I don't have a garage, but I am a mechanic. How complex is that process? something for the weekender in a parking lot, or would it be best to just have a shop do a good once over?

[still.southern]

Originally Posted by Dartmech

Ya I just got the bike, and I knew after the first few highway rides that something was wrong. Today I was able to confirm anything. It has to be rich I would think, filters and other items clogging would just make it lean out which would not suck the fuel down. Dang I guess i'll have to get somebody to check the carbs. I don't have a garage, but I am a mechanic. How complex is that process? something for the weekender in a parking lot, or would it be best to just have a shop do a good once over?

I haven't done it on a VT1100, but on my VT500 it's pretty easy. A good shop manual would help with getting the carbs out, but generally it's pretty self explanatory. Mine takes a phillips head screwdriver and a 12mm wrench or socket along with a pair of pliers. I usually just run the carbs dry and then open the drains into a towel before removing. Shouldn't be too bad in a parking lot...though admittedly I swapped a V6 Ranger engine on a gravel driveway in college, so I may be a little skewed. Once you have the carbs out just open the fuel bowls and check the jetting vs. the standard jets. Takes about an hour to two hours for me depending on how far I go into the carbs. Also make sure the choke is disengaging and nothing else looks torn or punctured. Beyond that I'd better let the VT1100 guys jump in.

Hope that helps!

[Canyon]

Go to my Garage site for the manual of your bike....
Click the pages link.
(Also in the manuals stickie but the description is wrong - thread locked so cannot be edited by members)

[dgraves49]

One quick check prior to pulling the carbs would be to look at the air filter. If it is real dirty or has a rodent nest in it, it would be like running with the choke on.

[John Hopkins]

18 mpg is about half what you might expect so are you running on one cylinder...

is your bike a California model..easy to spot by the beer barrel under the radiator..if it is don't attempt to remove the carbs without taking all round photos of the carbs and the pipes going to them at every stage of removal.

before you touch the carbs check the exhaust headers as soon as you start it next time, put your hand on them, if one is hot and the other is cold only one is working..

John.

[Dartmech]

Thanks for the help guys.
When I bought it I put my hand over each pipe and felt pulses from both. I wouldn't imagine it would run as well as it does around town on one cylinder.. but..I don't know for sure. ( my first v-twin ). I have a infrared thermometer I can take with me and catch the pipes right off the highway.
I will check on how to get to the air filter and check it. It did come from a dusty, country town so that is definitely a possibility.