Engine idle speed synchronization vacuum numbers

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gltriker
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Engine idle speed synchronization vacuum numbers

#1

Post by gltriker »

What I am looking for is average 1975-77 GL1000 synchronization session vacuum numbers that are observed when the intake and exhaust valves' lash clearance has been set at 0.006 inches. My bike is a 1975 unit.
Last edited by gltriker on Mon Jul 17, 2023 7:19 pm, edited 4 times in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
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^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
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Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
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Re: Engine idle speed synch session vacuum numbers ???

#2

Post by Whiskerfish »

Not exactly what you are looking for but, years back I did some readings for Randall of the difference between early and late 1000. They were both setup with .004 clearances. I still find it an interesting comparison. viewtopic.php?f=1&t=18015&hilit=Vacuum#p160748
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
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Re: Engine idle speed synch session vacuum numbers ???

#3

Post by redglbx »

Steve, just curious but do you happen to have the actual numbers that you took ? Any idea of what Randall was trying to do with them ?
Red 1976 oe owner
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#4

Post by gltriker »

:-D
Last edited by gltriker on Mon Jul 17, 2023 7:23 pm, edited 5 times in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#5

Post by gltriker »

tumb2 Engines with valves set at 0.006 inches and pilot screws set at 3 turns from seated
Last edited by gltriker on Mon Jul 17, 2023 7:24 pm, edited 2 times in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#6

Post by gltriker »

Whiskerfish wrote: Mon May 08, 2023 7:22 am Not exactly what you are looking for but, years back I did some readings for Randall of the difference between early and late 1000. They were both setup with .004 clearances. I still find it an interesting comparison. viewtopic.php?f=1&t=18015&hilit=Vacuum#p160748
A perfect example of what I need to know, Steve ! action1
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
redglbx
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Re: Engine idle speed synch session vacuum numbers ???

#7

Post by redglbx »

Cliff, I’m getting ready in the next couple of weeks to change the belts (10yrs old) and going to check the valve clearances . Also going to change the oil and the Dyna out in an effort to eliminate the exhaust popping at idle. So I’ll try to get those numbers but it may be a week or 3 before I get them. Patience.

So let me ask what you’re looking for here ?

One thing I’ll add is that Robins comments are spot on in that old thread. One thing I’ll add is that the stock 32mm early carbs are pretty much close to optimum for sizing, there’s not a lot left and if you do improve their flow some the can get sluggish. I find optimal carb sizing (on anything) should provide near to or absolute zero vacuum at full throttle at max rpm when measured at the manifold. Also cam timing was a big thing, the early cams have a lot of overlap which is why they have lower vacuum than the later 78/79’s. The optimum cam timing setting for your engine should give you the highest cranking compression, advancing the cams will improve the lower rpm’s and retarding will give you better higher rpm output, the hard part is tailoring that cam timing to meet your operating range, my dyno time was great for this. You will see a change in the vacuum signal as well. On the vacuum signal the 75-77’s have a pretty lazy vacuum signal that really allows the fuel to drop out of suspension (wets the manifold & head ports walls) which is part of why Honda jetted them so rich, to help minimize the cold bloodiness caused by this air column sluggishness.

The 75-77’s are really quite highly tuned vs the 78/79’s which focus’d more on low end & midrange power.

On my 76 I played with the cam timing from straight up to +/- 8 degrees and settled at +4 degrees. My highly modified 1100 carbs were a challenge where the smaller 31mm bodies give a stronger vacuum signal (more low speed response + torque) and the mods to improve the overall total flow w/o compromising the low speed vacuum signal. It was a real balancing act. Anyway I’ll get the vacuum numbers once I get into it !
Red 1976 oe owner
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#8

Post by gltriker »

redglbx wrote: Mon May 08, 2023 8:28 pm
snip-
So let me ask what you’re looking for here ?
I am presently re-Awakening trike after sitting, un-started for 3 years.
Last edited by gltriker on Tue May 09, 2023 11:37 pm, edited 1 time in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
redglbx
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Re: Engine idle speed synch session vacuum numbers ???

#9

Post by redglbx »

Cliff, couple of things in my opinion, a “bench” sync is only good to get things setup in the neighborhood.

The Nixon recommended .002in increase in valve lash shortens the cam duration & overlap so should provide an increase in compression and vacuum. I’ve been running mine that way for a couple of years now but not sure I will continue to, I’m not sure that there is a benefit or a detriment and plan to look closely at that once I get into my 76, looking at compression and vacuum at both .004in and .006in. We’ll see.

This might, maybe explain why my bike’s compression dropped off from the previous 185-195 psi to the current 160-165psi, the shortened cam timing afforded by the added .002in valve lash may be the cause,,,, maybe.

On my 76 LTD when I woke it up after setting in a warehouse on a shelf for years I had trouble with the valve lash closing up as I ran it which I think that was due to corrosion or something on the valve faces or seats that got beat off with use and allowed the clearance to close and got me to set things to the .006in. The clearance settled in and held the .004in clearance fine after about 1000mi.

On your bike,, the plugged catalyst’s would definitely cause lower vacuum numbers, definitely ! But a restriction on the intake side would increase those numbers. Also I would add that comparing vacuum numbers using different gauges cannot be used as absolute unless the gauge performance numbers are both ran on a calibration stand, same day. We simply don’t have that so at best they are only good for a loose comparison not an absolute.

Finally, if your bike runs good, ride it and enjoy it (don’t wake that baby though 😁) ….. Once I get into my 76 I will take plenty of notes and post results so we’ll see. This has got me curious about things particularly since there’s been so many things that I’ve modified on my 76 standard. But it may take a while since this is a fairly big undertaking and I just don’t have much ability for this kind of stuff since my back reconstruction as this stuff takes a toll.

Anyway, we’ll have some fun and see but I always go back to the comparison between my 76 and my friends 76,, mine has been fussed over and modified with the heads milled.040in , ported and polished heads and manifolds, highly modded carbs and once I found the mismarked flywheel t2/f2 settings and dynamically set the timing it just runs very well with lots of giddy-up. On the other hand my friends 76 is well tuned by him but has low compression numbers with some well below 100psi,, but you know what? It just runs, sweetly ! So just ride and enjoy them.

So hopefully I’ll get into mine this next week !
Red 1976 oe owner
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#10

Post by gltriker »

gltriker wrote: Mon May 08, 2023 11:36 pm
redglbx wrote: Mon May 08, 2023 8:28 pm
Last edited by gltriker on Mon Jul 17, 2023 7:26 pm, edited 1 time in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
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Re: Engine idle speed synch session vacuum numbers ???

#11

Post by digger »

Cliff said “I am presently re-Awakening trike after sitting, un-started for 3 years.”
Ran when I parked it. lolol Sorry, couldn’t resist. So many people advertise it as “ran when I parked it.”
1975 GL1000
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#12

Post by gltriker »

digger wrote: Wed May 31, 2023 5:56 pm Cliff said “I am presently re-Awakening trike after sitting, un-started for 3 years.”
Ran when I parked it. lolol Sorry, couldn’t resist. So many people advertise it as “ran when I parked it.”
yeah, that was kinda tongue-in-cheek silliness on my part ;)
goes along with, "Just needs a battery and gasoline with a little shot of Seafoam," too :lol:
Last edited by gltriker on Thu Jun 15, 2023 9:15 pm, edited 2 times in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
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Re: Engine idle speed synch session vacuum numbers ???

#13

Post by Fred Camper »

Glad to see you will soon be back in the saddle. Many of us are eagar for that day.
Proud member of the NGW Cartel (Rochester MI)
1977 GL1000 BADDOG (April 2012 BOTM)
1976 LTD - '993 LTD...and so it begins'

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Re: Engine idle speed synch session vacuum numbers ???

#14

Post by Whiskerfish »

I have done the water decarbonizing /scrubbing thing. It works but be sure to warn the neighbors. Looked like the shop was on fire.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
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gltriker
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Re: Engine idle speed synch session vacuum numbers ???

#15

Post by gltriker »

Whiskerfish wrote: Wed May 31, 2023 8:23 pm I have done the water decarbonizing /scrubbing thing. It works but be sure to warn the neighbors. Looked like the shop was on fire.
I will, Steve! :lol: :lol:
Last edited by gltriker on Mon Jul 17, 2023 7:27 pm, edited 2 times in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
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