84 GL1200 standard getting Very, very bad fuel mileage


Information and questions on GL1200 Goldwings (1984-1987)
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G-Wiz
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Joined: Wed Jun 15, 2016 11:31 pm
Location: Blaine, Washington
Motorcycle: 1984 GL1200 Standard

84 GL1200 standard getting Very, very bad fuel mileage

Postby G-Wiz » Wed Oct 05, 2016 9:34 pm



So this will be my first post ever. Yay. So, about 4 months ago I bought my grandads 84 GL1200 standard with 22k miles on it. The bike had been parked for roughly 5 years. I towed it home as it sill had the origional timing belts and tires not to mention it was parked for 5 years. Stripped it down in my garage. Replaced tires, timing belts, spark plugs, removed, drained, and thoroughly cleaned fuel tank, vacuum lines, fuel lines, fuel oil and air filters, rear diff\final drive oil, flushed all brakes and clutch, fuses, repaired short to ground in taillight and installed a new agm battery. I think the only thing that wasnt touched was the fork seals which I will be doing this weekend as the weather here in WA is starting to turn. I noticed after a couple of rides that the fuel mileage was horrible and there was a strong smell of fuel after a ride. So, I ordered a K&L rebuild kit as Randakks was out of stock and still is. I did notice that someone had already been in there somewhat recently because all of the carbs and jets were pretty well new and clean. One of the diaphrams on the carb slides was folded in which i assumed was the cause of the poor fuel economy. Put everything back together and synced correctly and have been riding all summer. Have put about 600 miles on the bike and still have horrible mileage. I am averaging about 15-17 mpg in town and 20-25 highway. I have changed spark plugs twice, oil 3 times, re lubed choke cable, brakes are free and no drag. I dont know what else to do. I am planning on pulling the carbs again to check the float levels again for a third time but not sure what else to do. I filled my tank again today after work with 51 miles on the trip meter and 3.3 gallons of gas which is pretty consistent. Am I overlooking something? What could be causing the poor mileage? Any advice would be more than appriciated as I would like to put some miles on this thing next summer.



sportsfreaked
Posts: 219
Joined: Fri Mar 13, 2015 7:23 am
Location: Independence, MO
Motorcycle: 1981 Honda Goldwing Interstate GL1100I
1985 Honda Goldwing Limited Edition gl1200

Re: 84 GL1200 standard getting Very, very bad fuel mileage

Postby sportsfreaked » Thu Oct 06, 2016 4:39 pm

Is fuel leaking into the crankcase at all? Do you still have the smell of gas when shutting off? It's obvious that you are losing gas somewhere. Just throwing this out there but have you checked the shut off valve to make sure it's not leaking. How about fuel filter? Just throwing some things out there to think about.
Thanks to all who answer and help. It is greatly appreciated!
Ed

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G-Wiz
Posts: 4
Joined: Wed Jun 15, 2016 11:31 pm
Location: Blaine, Washington
Motorcycle: 1984 GL1200 Standard

Re: 84 GL1200 standard getting Very, very bad fuel mileage

Postby G-Wiz » Thu Oct 06, 2016 6:48 pm

I did have fuel getting in the crankcase before the carb rebuild but not after. I am getting a very faint fuel smell every so often after shut off but not as bad as it was. Petcock and fuel lines are not leaking. I check everything over before and after every ride just to be sure. Fuel filter still appears clean. I replaced it with a clear filter so that I could monitor it. I am planning to change it again this weekend however just for good measure. Plugs are not fouled. I do get the typical smoking on cold startups but smells of oil, not fuel. I am at a loss as to where the fuel is going. I feel I should say that most of my rides are just to and from work which is only 2 miles down the road I normally take a longer route of about 5 miles so that I hear the fan kick on before im at my destination. Im sure the short trips are contributing to the poor mileage but 16-17mpg still seems wrong.

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G-Wiz
Posts: 4
Joined: Wed Jun 15, 2016 11:31 pm
Location: Blaine, Washington
Motorcycle: 1984 GL1200 Standard

Re: 84 GL1200 standard getting Very, very bad fuel mileage

Postby G-Wiz » Fri Oct 07, 2016 8:34 pm

So I rechecked everything after work today and found the vacuum line to the advance box was pinched. Also ordered a new air cutoff valve that should be in next week. Gonna take apart the carbs again this weekend and re measure everything just to make sure. Also since I will be replacing my thermostat I plan to recheck the timing belts. If anyone has any advice on what else to check while I'm in there please let me know.




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