Low gauge reading


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walker70
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Location: Headland,Alabama
Motorcycle: 1986 Honda Goldwing Aspencade

Low gauge reading

Post by walker70 »



Hi,have not been here in a while,got my bike out to change the carburetors with a set I cleaned up and put new parts on the inside,put them on and was syncing them up and this is what the gauges are reading,three of them are good but one drops low like it has no vacuum to it,maybe a bad oring at that carb?,I have checked the hoses on the gauges and they look good along with with the adjuster valves,ideas.??? :D





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Maz
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Re: Low gauge reading

Post by Maz »

Check the manifold 'O' ring and rubber joint and that the carb top is tight. It may not be the carb at fault. Check compressions on all cylinders. May be a leaky valve or poor ring/bore sealing.
Maz
Ironically, Common Sense is the LEAST common of all senses!

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DenverWinger
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Re: Low gauge reading

Post by DenverWinger »

If I'm reading the gauges correctly three cylinders are reading 5" Hg and the other 13" Hg, so that's high vacuum, not low vacuum. As stated check for vacuum leaks (5" seems a little low on the three cylinders) and proceed with the balance operation, the cylinder reading 13" needs more throttle.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
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walker70
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Re: Low gauge reading

Post by walker70 »

Thanks for the info,but I have used Steve Saunders video for syncing the carbs and it shows the gauges reading like the three on my gauge all across.

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DenverWinger
Posts: 1522
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1980 GL1100 STD Vetter (2005-)
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1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Low gauge reading

Post by DenverWinger »

That's right, you need to adjust the linkages so the cylinder with the high vacuum reading matches the other three.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark

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Maz
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Motorcycle: 1975 GL1000K1
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1993 Suzuki GS500E

Re: Low gauge reading

Post by Maz »

Apologies, I read your post and didn't pay much attention to the picture. Denverwinger is spot on with his advice.
Maz
Ironically, Common Sense is the LEAST common of all senses!

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patbrandon1
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Re: Low gauge reading

Post by patbrandon1 »

I know you may have already done this step, but...

Did you check that all the gauges are reading the same by hooking each one individually one at a time to the #3 and see if each of them read the same? One of the gauges could be out. Have you used this sync set of gauges before? had you synced the previous carbs?

I believe something is just leaking vacuum, unless the gauges are off.

Good luck and please keep us posted.

walker70
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Joined: Fri Apr 08, 2016 2:53 am
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Re: Low gauge reading

Post by walker70 »

Yes,I checked like you say and it is a vacuum leak and I am going to replace all the orings,now I have a question,I have the intake orings but what I am having trouble getting are the ones that go between the plenum and the carbs,dealer says not available thru them anymore,anybody have an idea,I have checked on ebay using the oem part# but no luck,thanks. :D

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Maz
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Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: Low gauge reading

Post by Maz »

walker70 wrote:
Thu May 09, 2019 1:54 am
Yes,I checked like you say and it is a vacuum leak and I am going to replace all the orings,now I have a question,I have the intake orings but what I am having trouble getting are the ones that go between the plenum and the carbs,dealer says not available thru them anymore,anybody have an idea,I have checked on ebay using the oem part# but no luck,thanks. :D
Try Randakks, but, as DenverWinger said, that gauge is showing a HIGHER vacuum than the other 3, so opening the throttle plate more on that cylinder (using the sync adjuster) will bring that vacuum reading down to match the other 3.

Maz
Ironically, Common Sense is the LEAST common of all senses!

walker70
Posts: 369
Joined: Fri Apr 08, 2016 2:53 am
Location: Headland,Alabama
Motorcycle: 1986 Honda Goldwing Aspencade

Re: Low gauge reading

Post by walker70 »

Sorry about calling it a low reading,I sometimes get a bit Dyslexic,I know it was reading high,Duh.



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