Help with a vacuum leak


Information and questions on GL1500 Goldwings (1988-2000)
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eekster
Posts: 10
Joined: Wed Nov 16, 2022 9:39 pm
Location: United States, Tucson - AZ
Motorcycle: 94 Helix, 06 Burgy 400, TW 200, R80G/S, 94 G/W 1500SE

Help with a vacuum leak

Post by eekster »



I just recently acquired a 94 with 28K on the clock. I knew there would be some issues to deal with for a bike with low miles at this age.
When I drove it home, I noticed the fuel gauge had dropped noticeably on a 45 mile drive, I didn't drive it after that due to the front tire being extremely wore out/bad.

Things I noticed. Idle was off/amiss...couldn't quite place any real solution just yet. Also, when checking bike out originally, bike was outside in a pole frame tent with tarp. Exhaust pipes where pointing out "door" one side of tent was partly rolled up. On cold start to fully warm it took many minutes..let's say 5-7 minutes...the exhaust gas fumes where pretty bad...and this is outside and there is a breeze!

So, after getting home and letting it idle in garage, I noticed there was some engine oil/grimey/goo I could wash off with brake cleaner at the back of right bank of cylinders, just behind last spark plug. So I shot brake cleaner on it in that general area and the rpms went up, idle smoothed out! This was at best...a 2 second blast of cleaner.

Now, my question is, what vacuum hoses are in the lowest part of engine bay? I have removed the carbs, the black rubber mat, the infamous 90 degree bend hose is not compromised ( but is to be replaced). I can't seem to find anything that might give me a clue as to what lies between and under the intake manifolds as far as vacuum hoses go.

Any ideas on what I am looking for?


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newday777
Posts: 2406
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Help with a vacuum leak

Post by newday777 »

Sorry I haven't been into the vacuum hoses, but a 2 second blast is too long to pinpoint a leak.
Very short, intentional shots are the only way to find specific vacuum leaks.
User avatar
newday777
Posts: 2406
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Help with a vacuum leak

Post by newday777 »

The 1st thing that came to mind as I read your post is your petcock is the cause of how rich it was running and lots of gas used.
Be sure to rebuild your vacuum petcock as the rubber in them crack. I've read of guys going through 3/4 of a tank in 75 miles, basically dumping unspent fuel on the road as you ride. It also will give a hunting idle when it leaks.
User avatar
newday777
Posts: 2406
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Help with a vacuum leak

Post by newday777 »

User avatar
eekster
Posts: 10
Joined: Wed Nov 16, 2022 9:39 pm
Location: United States, Tucson - AZ
Motorcycle: 94 Helix, 06 Burgy 400, TW 200, R80G/S, 94 G/W 1500SE

Re: Help with a vacuum leak

Post by eekster »

Thanks for replies. I did see a petcock rebuild kit in box that manual and a few. other assorted items that came with bike, easy enough to do.

Yea, a 2 second blast ( at best- maybe it was a second) however I wasn't even thinking a vacuum leak would be discovered, just cleaning some goo off engine and that was a secondary discovery!

I'll spend more time today looking around the lower engine bay area and see what I can discover. Bike definitely perked up when that brake cleaner entered the engine bay area.
User avatar
eekster
Posts: 10
Joined: Wed Nov 16, 2022 9:39 pm
Location: United States, Tucson - AZ
Motorcycle: 94 Helix, 06 Burgy 400, TW 200, R80G/S, 94 G/W 1500SE

Re: Help with a vacuum leak

Post by eekster »

Did the easy petcock rebuild. Looked way down in the engine bay...I can see 6 rubber hoses coming off intake and 4 (?) chrome looking pipes ( I'll just say at the 4 corners of engine bay). These chrome pipes have o-rings under them ( from what I can see on parts diagrams I look at ) and then there are those 6 hoses...anyone have any experience doing those?
User avatar
newday777
Posts: 2406
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Help with a vacuum leak

Post by newday777 »

Again, no I don't. But seeing you are in the high heat desert, change the rubber hoses while you are in there.
User avatar
eekster
Posts: 10
Joined: Wed Nov 16, 2022 9:39 pm
Location: United States, Tucson - AZ
Motorcycle: 94 Helix, 06 Burgy 400, TW 200, R80G/S, 94 G/W 1500SE

Re: Help with a vacuum leak

Post by eekster »

Ordered some parts, now I wait...
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Snowmoer
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Location: Cedar City UT
Motorcycle: 2012 GL 1800
1977 GL 1000
2012 KLR 650

Re: Help with a vacuum leak

Post by Snowmoer »

The chrome tubes are coolant tubes. There are also rubber hoses that are a little bigger than the vacuum hoses that are also coolant. I replaced just about all the vacuum hoses on my 88. They are metric and you will not find them at the local auto parts store. I got the sizes off the parts fiche when I replaced mine. I bought bulk metric hose off Amazon. I just cut new hose to fit the length of the old one. From what I remember, there were only one vacuum hose on the middle of the intake manifold on each side. All the rest went to different control parts of the bike away from the motor. There are also a bunch of them on the carbs. If you don't have a shop manual, get one so you have the vacuum hose diagram.
User avatar
newday777
Posts: 2406
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Help with a vacuum leak

Post by newday777 »

Snowmoer wrote: Wed Jan 11, 2023 11:27 am The chrome tubes are coolant tubes.
PAR tubes not coolant tubes.
User avatar
eekster
Posts: 10
Joined: Wed Nov 16, 2022 9:39 pm
Location: United States, Tucson - AZ
Motorcycle: 94 Helix, 06 Burgy 400, TW 200, R80G/S, 94 G/W 1500SE

Re: Help with a vacuum leak

Post by eekster »

So....here I am many weeks later and here are some updates.

I managed to get to bottom of engine bay and sound up replacing a lot of coolant hoses and vacuum lines. Coolant lines got traditional coolant hoses while the vacuum ones got silicone lines. Found the remains of a dead mouse in engine bay area as well!

Since the carbs were removed....I went ahead and took them apart, cleaned and replaced rubber o-rings. While I had them that far apart, I went ahead and replaced the rubber diaphragm as well. I managed to botch the slide of one carb assembly while doing this. I was using JBM diaphragm ( I have used JBM in the past and have been very pleased with product) so, after a little searching, I found and ordered some saber slides...another good product!

As long as bike was down for this kind of maintenance, I went ahead and upgraded shift shaft, installed LED headlights and corner lights as well ( now the corner lights are always on). Petcock was rebuilt, fuel filter replaced. The subfilters and all fluids got replaced.

When front tire was replaced, the fork seals got renewed. One was drooling...so why not? Timing belt got replaced while front end was out of the way.

I'm sure there were a few other things that I did but cannot recall right now. However, once all maintenance was done and bike readied for initial road test...there wasn't really any reason to keep doing other work to it...time to ride!

I started with a few miles around the neighborhood...so far, all was good. Carb work resulted very decent results. Very peppy and responsive. Time to put a couple of short rides together. It's about this time an old friend contacted me about visiting a mutual friend down in San Felipe. I felt with 50 or so miles of test rides wasn't enough to commit bike for that big of ride so soon. However, after thinking it over, I told my buddy that I thought we should also go about halfway down the Baja as well (Bay of Angeles...I had always passed this place up on previous trips when I wore a much younger mans clothes) He agreed and we decided to leave within a couple of days.

All said, I was able to put a total of 70 miles of test rides before we took off. The first fill up of gas revealed that the 65 mph or less range yielded 43 mpg! That was good news. The rest of the fuel readings were after long runs at 75 plus...36 mpg average every tank. So far this was good, weather was perfect and the ride down Baja and back got us a 1300 mile trip.
Getting back across the border in a Sunday afternoon...was not the best plan of action. We sound up splitting entry line traffic for about one mile. Thought this was pretty bad and dicey torture. In the end we both did fine, took us about 20 minutes to accomplish this and return entry into U.S. was a breeze!

And? It all went well! 😀 The only problem we had was a seat bolt vibrated out on my friends Harley. All the gas from various stations was good, no problems. Some stations (in the middle of proverbial no where) had attendant with card reader for gas purchases. Looking back, I will have to say that this forum helped me out and get through the maintenance issues and some of the updates. Thanks to all who contribute so others can find the resources they find appropriate.

As soon as I can get back home I can upload pics. I am currently helping my daughter recover from her first big motorcycle accident...she is gonna be fine and we all ready are scheming and dreaming about a trip to Alaska! Grandma isn't impressed at the moment!


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