Too Much Vacuum?


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RockportDave
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Too Much Vacuum?

Post by RockportDave » Sat May 19, 2018 10:08 am



After rebuilding carbs, fixing all vacuum leaks, replaced both carb boots, etc I am getting too much vacuum to use my Motion Pro SyncPRO.
I used it before the last overhaul of the carbs and it worked flawlessly. I have the syncing screws turned counterclockwise on the SyncPRO (open), but when I start the bike both blue fluids run to the top. I pulled a cap off the tee to creat a leak and it works as it is supposed to, about 1/3 up.
Any suggestions on what is going on?
Thanks,
Dave








1999 GL1500SE 5th Goldwing through the years

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RockportDave
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 19, 2018 10:35 am

Had the main side connected to the #1 vacuum Port instead of #6 green, so I changed it and still have fluid going to the top of sync tool.
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Re: Too Much Vacuum?

Post by thrasherg » Sat May 19, 2018 10:43 am

your air filter isn't completely blocked? cant think what else would cause such a high vacuum.. Does the engine idle?

Gary

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RockportDave
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 19, 2018 2:28 pm

Idles at 800-850 with no surge. Runs great low RPM, midrange and on it hard.
We’re gonna ride this afternoon when it cools off. I can check the mileage then.
I adjusted the sync screw as best I could by listening to the engine, but hard to tell where it needs to be without a gauge.
I’ll get 2 vacuum gauges and see what it is actually pulling and sync with them.
Dave
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terryt
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Re: Too Much Vacuum?

Post by terryt » Sat May 19, 2018 3:26 pm

Are the restrictors still in the vacuum hoses .

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RockportDave
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 19, 2018 4:20 pm

Restrictors are in. I used it two weeks ago when I bought it and it worked fine.
I checked all vacuum hoses while I had the carbs off and found no more bad ones. I also replaced the carb insulators (boots) with new ones. I noticed the old ones would move on the intake so I figure they were leaking also.
I’ll call Motion Pro Monday and see what they say.
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 19, 2018 8:53 pm

Had a nice 100 mile ride with 20 mph wind. After all the idling while checking the bike, running 65-75 mph (speed limit down here is fast), and the wind, we still got 30 mpg two up. It’s able to move right up to speed from 1000 rpm in OD.
Dave
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ct1500
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Re: Too Much Vacuum?

Post by ct1500 » Sat May 19, 2018 9:00 pm

Common issue when using those gauges on the 1500 engine. My solution IIRC was to use two tubes of the tool for each intake manifold and/or lower the engine RPM a bit. Their fluid is too lite IMO.
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 19, 2018 9:39 pm

I was wondering if that would work. I only have 1 vacuum tee. I’ll pick one up tomorrow and try it.
I idled it down well below 500 per the bike tach and it still pulled the fluid to the top.
I put my finger on the vacuum adapters and it is definitely pulling good vacuum.
Thanks for the info.
Dave
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 26, 2018 3:53 pm

ct1500,
Took your advice and connected two lines on each side, but too much vacuum for the SyncPRO.
Got two tees and connected one line on each side leaving the tee open. Was able to get the carbs balanced and it seems to be right.
Thanks,
Dave
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ct1500
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Re: Too Much Vacuum?

Post by ct1500 » Sat May 26, 2018 6:23 pm

Well then it must have been smaller restrictors I concocted. My mercury stix were on loan and have since gone back to use them. BTW what line did MotionPRo sing to you as to why it was not working as designed?
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Re: Too Much Vacuum?

Post by RockportDave » Sat May 26, 2018 7:04 pm

Had a busy week at work and never had a chance to contact them. I’ll try to contact them after the holiday and let you know.
I plan to get a set of regular vac gauges and re- sync the carbs. I’m curious to know just how much vacuum it actually has.
Seems to be running very smooth and I will check the mileage on my next tank. The wife is usually with me whenever we have a chance to ride so it should be in the mid 30s. Been using premium fuel only trying to stay away from the corn, but I’m not sure if the premium is corn free.
Thanks again for the advice.
Dave
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topgun
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Re: Too Much Vacuum?

Post by topgun » Sun May 27, 2018 7:21 pm

Are you starting from scratch each time you connect and setting the calibration screws using the 4way Tee?
https://www.motionpro.com/a/syncpro-carb-tuner-08-0411

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Re: Too Much Vacuum?

Post by RockportDave » Sun May 27, 2018 8:56 pm

Yes. The first time I rebuilt the carbs I connected it and it worked flawlessly, but the bike had a surge at idle and was rough running at low rpm. I rebuilt the carbs with new Honda jets, jet holders, set the float levels the correct way and replaced the isolators (boots) under the carbs.
Now to keep the SyncPRO fluid from going completely out of the clear tubes I have to leave an open vacuum on a tee on each side and it still goes in the upper levels.
The old isolators would turn on the intakes with the clamps tight, so I’m sure it was leaking vacuum there.
Dave
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Re: Too Much Vacuum?

Post by RockportDave » Fri Aug 24, 2018 10:35 am

ct1500 wrote:
Sat May 26, 2018 6:23 pm
Well then it must have been smaller restrictors I concocted. My mercury stix were on loan and have since gone back to use them. BTW what line did MotionPRo sing to you as to why it was not working as designed?
ct1500,
I finally spoke to Motion Pro and they said they have had problems on the GL1500. He recommended I add more fluid to the reservoirs and leave about a 1/8” air gap. I haven’t tried yet.
I did purchase a set of sync gauges that should be here tomorrow and I will sync the carbs. After a proper sync, I will set the idle screws per the manual.
I am curious to see what kind of vacuum I’m pulling at idle with no leaks and new carb insulators on it.
Dave
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rrago
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Re: Too Much Vacuum?

Post by rrago » Wed Aug 29, 2018 10:51 am

I have the same issue using my Morgan carbtune. The Gl1500''s simply pull too much vacuum for the sticks (3 cylinders per carb), I had to fabricate the ATF 5- foot column you may have seen here or elsewhere. It works better for me, anyways.

Add to that issue, my wife's Bonneville gets synched with software, so the Morgan is useless for that too! Anyone want a Morgan carbtune? lol

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RockportDave
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Re: Too Much Vacuum?

Post by RockportDave » Wed Aug 29, 2018 12:11 pm

I ordered a set of 4 vacuum gauges on eBay on 8/21 with guaranteed delivery of 8/25. Vendor is in Pasadena Tx, 200 miles away so it should make it by 8/25. On 8/26 I contacted the vendor through eBay and they said it was sent out USPS on 8/22. USPS tracking shows a label made, but that is as far as it went. Said they will send another out ASAP and sent it USPS again. This time tracking went as usual. The label shows it was sent 8/27.
Finally got the gauges today, but my 6 days off are ending today and I have to return to work 150 miles away. Should get the carbs synced and the idle screws set this coming 3 day weekend.
Dave


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Re: Too Much Vacuum?

Post by RockportDave » Sat Sep 01, 2018 8:02 pm

Finally got the time to sync the carbs and set the idle drop. I set the idle drop twice just to be sure it was right. Will check the mileage and see if it helps. Averaging 35 mpg.
Also found it is pulling 14 in. vacuum at idle.
Dave
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Re: Too Much Vacuum?

Post by RockportDave » Sun Sep 02, 2018 10:36 pm

Had a nice ride today and averaged the usual 35 mpg. Ran good all day.
Next move is to moly lube the drive shaft splines and rear drive splines.
Dave
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Re: Too Much Vacuum?

Post by RockportDave » Sat Sep 15, 2018 4:09 pm

Bought a Colortune and tried it out today. Got a nice blue flame at idle and up to 2000 rpm on one cylinder. Guess the sync and idle drop is right. Runs great.
Dave






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Re: Too Much Vacuum?

Post by RockportDave » Sat Oct 13, 2018 3:00 pm

Since syncing the carbs and adjusting the idle drop I have been getting 36.6 mpg consistently. Most is 2 up riding, but when alone I do get in the throttle.
The bike cranks, idles and runs great.
Dave


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