Air Idle Jet Question

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Dr. Frankenstein
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Air Idle Jet Question

#1

Post by Dr. Frankenstein »

I've been reading about the 'Air Jet Off-Idle' problem here in the forum, and was wondering: the soldering fix I read about, what does that do, exactly?

I pulled my #4 air idle jet and it's a Keihin 110; I *assume the other three are the same, but I don't remember from when I rebuilt the carbs... is that the correct jet size, or is there another jet that does a better job...and what size does the soldering-fix make the jet, the same as a 110? And what effect does it have on the idle/pickup when you do it?

My bike runs fine (so far), but I've noticed a hard-to-define little 'issue' when I roll on the throttle - it seems to be a little sluggish unless I crank it, then she sits right up and Rolls really smoothly! But I'm wondering if that fix, or new jets would make it even smoother... ? What would be a good size jet to buy?
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Whiskerfish
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Re: Air Idle Jet Question

#2

Post by Whiskerfish »

110 is what came stock on the 75 and 77 carbs.
No sense rewriting what has been written below
https://www.randakksblog.com/how-to-cur ... /#more-241
"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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Dr. Frankenstein
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Re: Air Idle Jet Question

#3

Post by Dr. Frankenstein »

Yes, I read that - Randakk calls for the use of a Honda #98 air jet, but since I can't find a #98, I Did find a Keihin #100 - rather than soldering and re-drilling, would that work?
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gltriker
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Re: Air Idle Jet Question

#4

Post by gltriker »

Dr. Frankenstein wrote: Fri Jul 16, 2021 11:49 am Yes, I read that - Randakk calls for the use of a Honda #98 air jet, but since I can't find a #98, I Did find a Keihin #100 - rather than soldering and re-drilling, would that work?
Yes, they will work, John. No resizing required. tumb2
In the text of Randakk's article
snip:
"3. Easy, but costs about $25: Secure 4 replacement jets from SUDCO with Keihin Part #99101-124-100 (SUDCO part # is 99101-ZF5-1000). These have the right size orifice for correction (size #100), but they aren’t sized to screw into the elbow. Instead, here’s what you do. Remove the stock jets (you won’t be using them!). Then insert the jets from SUDCO into the end of the vacuum tube nearest the elbow. Push it in exactly 5/8″ using a drift or piece of dowel. Make sure the slotted end is oriented away from the elbow. Re-attach the vacuum tube and you’re done."

I could not remember what year your monster is. Had to thumb back through your Topics to find it. A 1975 GL1000. ;)

Please add that information into your User Profile for the Forum's future quick reference. ;)
(should it be worded, for the Forum's quick future reference :lol: )

Ciao for now! :-D
Last edited by gltriker on Fri Jul 16, 2021 5:24 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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Whiskerfish
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Re: Air Idle Jet Question

#5

Post by Whiskerfish »

I have one set with the air jet mod (solder and drilled) done. They were built years ago by Pete with "proprietary tweaks" special for Randakk's show bike. I have been through them twice now and can not figure out what else he did to them but they are not impressive. Idle is ok but not great, acceleration is again okay but not great and they struggle to get 30 mpg riding conservatively. I have checked the other jets and the numbers are all good but I have no way to measure them. I am fairly certain he changed other things so unfortunately it is not really a good evaluation of the air jet mod.
"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: Air Idle Jet Question

#6

Post by gltriker »

Dr. Frankenstein wrote: Fri Jul 16, 2021 10:32 am I've been reading about the 'Air Jet Off-Idle' problem here in the forum, and was wondering: the soldering fix I read about, what does that do, exactly?

I pulled my #4 air idle jet and it's a Keihin 110; I *assume the other three are the same, but I don't remember from when I rebuilt the carbs... is that the correct jet size, or is there another jet that does a better job...and what size does the soldering-fix make the jet, the same as a 110? And what effect does it have on the idle/pickup when you do it?

My bike runs fine (so far), but I've noticed a hard-to-define little 'issue' when I roll on the throttle - it seems to be a little sluggish unless I crank it, then she sits right up and Rolls really smoothly! But I'm wondering if that fix, or new jets would make it even smoother... ? What would be a good size jet to buy?


To help, Dr. , Did you know Keihin jet numbers identify their orifice' internal diameter dimension ,
precisely measured in hundredths of 1.00 mm.

A #100 jet = 1.00 mm. 1.00 mm = 0.03936 inch close enough to round up to 0.040 inch

Now you know. The Keihin jet number scheme. :shock:

Now you know how to calculate The Difference between internal diameter jets. a #100 -#98 = 0.02mm = 0.0008 inch. :shock:
Can you imagine .......
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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Dr. Frankenstein
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Re: Air Idle Jet Question

#7

Post by Dr. Frankenstein »

"A #100 jet = 1.00 mm. 1.00 mm = 0.03936 inch close enough to round up to 0.040 inch..."

Yah, I get it...pretty much too small of a difference to Make a difference...! That's like, what...? Four Hundredths of an inch?? (Dude, I SUCK at numbers...took me three years in Algebra II in high school to get Out of it. Geometry too - put me on a pool table though and I'll be drinking beer for free all night long...Challenge Accepted.)

True Story: When I was Much younger, I got off the bus at my duty assignment in Europe - A long time ago in a galaxy far, far away - the orderly comes to pick up my bags -
"Are you Sergeant So-and-So..?"
"Yes, I am..."
"You from Montana?" (My last duty station)...
"Yes, I am..."
"Do you play pool..?"
"Yes, I do..."
"I heard about you."
And this was in Europe! Blew my frickin' mind...(turns out I got posted to the same base as a friend of mine. Small world).

Of course, I'm older now...


So Cliff, what you're saying is, that a #100 jet Will work...? Or is the soldering thing the best way to go?
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gltriker
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Re: Air Idle Jet Question

#8

Post by gltriker »

Dr. Frankenstein wrote: Fri Jul 16, 2021 11:27 pm "A #100 jet = 1.00 mm. 1.00 mm = 0.03936 inch close enough to round up to 0.040 inch..."

Yah, I get it...pretty much too small of a difference to Make a difference...! That's like, what...? Four Hundredths of an inch?? (Dude, I SUCK at numbers...took me three years in Algebra II in high school to get Out of it. Geometry too - put me on a pool table though and I'll be drinking beer for free all night long...Challenge Accepted.)

True Story: When I was Much younger, I got off the bus at my duty assignment in Europe - A long time ago in a galaxy far, far away - the orderly comes to pick up my bags -
"Are you Sergeant So-and-So..?"
"Yes, I am..."
"You from Montana?" (My last duty station)...
"Yes, I am..."
"Do you play pool..?"
"Yes, I do..."
"I heard about you."
And this was in Europe! Blew my frickin' mind...(turns out I got posted to the same base as a friend of mine. Small world).

Of course, I'm older now...


So Cliff, what you're saying is, that a #100 jet Will work tumb2 ...? Or is the soldering thing the best way to go? :IDTS:
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: Air Idle Jet Question

#9

Post by Fred Camper »

Made my bike easier to launch and easier on the clutch. Easy to solder and drill with no parts needed.
Proud member of the NGW Cartel (Rochester MI)
1977 GL1000 BADDOG (April 2012 BOTM)
1976 LTD - '993 LTD...and so it begins'

You should remember that it's peace of mind you're after and not just fixing the machine. R.Pirsig
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