Only getting around 20MPG


Information and questions on GL1500 Goldwings (1988-2000)
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kyleboedeker
Posts: 28
Joined: Mon Apr 08, 2019 9:48 am
Location: St. Louis, MO USA
Motorcycle: 1988 GL1500 Aspencade

Only getting around 20MPG

Post by kyleboedeker »



Hey guys,

I recently picked up an 88 Gl1500A and have been trying to do all the maintenance. So far i've done engine oil, coolant, timing belts, spark plugs and a full bottle of seafoam through the gas tank. But I noticed that my gas mileage has been pretty poor. Only around 20mpg. Note, I mostly ride around the suburbs, so I know i'm not going to be getting 40mpg + like some of you. But I'm wondering if there is anything I should look at to improve the mpg. Sync the carbs? Rebuild the carbs? I'm not super knowledgeable about working on these bikes - the timing belt change was the most intense mechanical work i've done, so if that's the case, should I take it to a mechanic to try to sync or rebuild the carbs? Or is it feasible to do myself? Or is there something else I should be looking at?



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RBGERSON
Posts: 3233
Joined: Tue Mar 09, 2010 7:57 am
Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: Only getting around 20MPG

Post by RBGERSON »

Start with easier stuff first check teh plugs how do they look? light tan or fouled???
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

kyleboedeker
Posts: 28
Joined: Mon Apr 08, 2019 9:48 am
Location: St. Louis, MO USA
Motorcycle: 1988 GL1500 Aspencade

Re: Only getting around 20MPG

Post by kyleboedeker »

RBGERSON wrote:
Mon Apr 22, 2019 1:24 pm
Start with easier stuff first check teh plugs how do they look? light tan or fouled???
So I just replaced the plugs a couple weeks ago. Should I pull them again and look at them now?

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bluthundr31
Posts: 561
Joined: Tue Jul 11, 2017 11:43 pm
Location: Morgan Hill, CA.
Motorcycle: 1991 GL1500 Interstate (Cinnamon Beige)

Re: Only getting around 20MPG

Post by bluthundr31 »

If your new ride had been "sitting" for awhile when you bought it, it would take 4-8 tanks of gas (with Seafoam ofcourse, mixed at about 2 oz/gal) to clean up those carbs. You want to clean up your idle jets so keep your RPM's around 2K in city driving. Freeway riding is "flow-of-traffic" obviously. Those carbs were never meant to work with corn (ethanol crap) and they HATE being ignored for awhile. Be patient, those carbs will clean up and your mileage should quickly increase into the mid-30's. If the bike doesn't idle smoothly, it'll smooth out soon and your mileage will become more "normal".

kyleboedeker
Posts: 28
Joined: Mon Apr 08, 2019 9:48 am
Location: St. Louis, MO USA
Motorcycle: 1988 GL1500 Aspencade

Re: Only getting around 20MPG

Post by kyleboedeker »

bluthundr31 wrote:
Mon Apr 22, 2019 3:57 pm
If your new ride had been "sitting" for awhile when you bought it, it would take 4-8 tanks of gas (with Seafoam ofcourse, mixed at about 2 oz/gal) to clean up those carbs. You want to clean up your idle jets so keep your RPM's around 2K in city driving. Freeway riding is "flow-of-traffic" obviously. Those carbs were never meant to work with corn (ethanol crap) and they HATE being ignored for awhile. Be patient, those carbs will clean up and your mileage should quickly increase into the mid-30's. If the bike doesn't idle smoothly, it'll smooth out soon and your mileage will become more "normal".
Yeah, the guy I bought it from only put about 100 miles on it during the year he had it and apparently he got it from a dealer. So who knows how much it sat over the last few years. I will stop and get some more sea foam and keep running it through and see how that does. Thanks!

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AZgl1800
Posts: 2417
Joined: Thu Oct 30, 2008 2:46 pm
Location: Lake Oologah Indian Territory USA
Motorcycle: '02 GL1800
2009 Piaggio MP3 250cc

Re: Only getting around 20MPG

Post by AZgl1800 »

I bought a '94SE in Glendale, AZ that had been sitting up for 3 years.

It ran like crap, but, as I was a working guy, and made a 36 mile 'round trip everyday, I decided to just Sea Foam it.

Took about 3 to 5 months, but it did the job, and ran smooth, idled correctly, and I never opened up the carbs.

I did patch/replace some vacuum lines, including the big one under the rubber diaphragm.
that one, I sealed it off with some rubber cement instead of replacing it.....


~John

'02 GL1800
2009 Piaggio MP3 250cc

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