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Discussion Starter · #21 · (Edited)
Hi there ! .

I occasionally get ATLAS HONDA parts for my 1984 CB125S from Pakistan, are there no Honda dealer there ? .

I'm not familiar with the ASV system but any time you find a crack or hole in a diaphragm it's bad .

PZ26 kits should be available on line, what's the year or production of your bike ? .

Trails : THANK YOU for that PZ service file ! .

I have the PZ27, pictured but not mentioned in the booklet .

Is there perhaps a link to a Pakistani Honda parts place ? .

TIA,
Hi,
Hi there ! .

I occasionally get ATLAS HONDA parts for my 1984 CB125S from Pakistan, are there no Honda dealer there ? .

I'm not familiar with the ASV system but any time you find a crack or hole in a diaphragm it's bad .

PZ26 kits should be available on line, what's the year or production of your bike ? .

Trails : THANK YOU for that PZ service file ! .

I have the PZ27, pictured but not mentioned in the booklet .

Is there perhaps a link to a Pakistani Honda parts place ? .

TIA,
Hi Nate, Good to know that you are still getting parts for 1984 CB125S because a couple of years or a decade later they change the size of some internal components of engine and stop manufacturing the parts for very old models CB's are not present here anymore.

In Pakistan Honda for motorcycles company is named as " Atlas Honda". It is like a subbranch of real Honda. Everything is governed by real Honda since Japanese are not producing these old machines so they give license to 3rd world countries for manufacturing and took some share. CG 125 And CD 70 are still the main stream motorcycles here. The design is still the same 80s-90s, with little changing like Air Suction Valve (ASV), CDI & black painted muffler instead of chrome. This year they made some more changes in engine as well like increased or decreased the size of some internal components.

The production model of my byke is 2017. from 2004 to 2021 are identical. from 1990 to 2004 there was no ASV. earlier 90's were on point system.

There are many Honda dealers in every city who maintain users motorcycle also they have all the parts of these bykes. Yes online kits are also available. Today i purchased a kit containing fuel mixture screw and RPM screw, because last night i found that there was no rubber o-ring and washer inside my fuel mixture screw, the guy at honda service center must have lost it. I purchased it from Honda dealer near me. It costed less than us USD $. its like 0.7 $.

I will first fit it then test > if not fixed then i will delete ASV diaphragm from carb and see.

link for honda website: Atlas Honda - Homepage - Atlas Honda
but i dont think they ship to outside or even with in pakistan. There are some pakistani websites which ship parts with in pakistan like Online Shopping in Pakistan: Fashion, Electronics & Books - Daraz.pk
If your machine need something crucial i could help you may be by asking from dealer.

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Discussion Starter · #22 ·
OHHH! This is the bike that has plastic and stuff stuffed into the place where there used to be an air cut off valve.
Would have been good to lead off with that little tidbit of information... Just sayin

"
Fully closing mixture screw means no fuel and oil and air dont produce bang.
A fully closed fuel supply screw and still running engine means its sucking fuel from some other place in carb "
Quote - UserXXX

Yes sucking fuel from someplace like the needle jet. (Yep, even at idle). Or maybe from the "rigged" air cut valve stuffing job too?
A leakdown and compression test will give a clue as to the possibility of oil contributing to a richer idle speed mixture but most likely your carburetor just needs to be fixed.

What is an ASV?
What year model bike are we talking about?

S F
No that was my other byke whose air cut off was deleted. and its working fine. Alhamdulillah.
 

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Thank you very much ! .

I got my PZ27 factory carby from Pakistan, it was made in Japan .

I also got a factory chrome muffler from Pakistan, it was an ATLAS HONDA product, I mentioned them before, I don't have a regular parts connection in Pakistan, I will go check those two closely .

Most of the CG125 internal parts as the same as the 1980's & 1990's CB125's as are the wheels, tires, chains & sprockets, clutch discs .

I only seem to find cheap Chinese dress up parts and I only want stock bits and bobs, Honda branded if possible .

Sadly the 125CC Motos are not popular here in the U.S.A., they're $1 sellers worldwide as they're reliable and keep running in severe duty even when poorly maintained .

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My little red Honda close to 1,000 miles from home far into the Desert .
 
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Discussion Starter · #24 ·
Thank you very much ! .
( you welcome :) )

I got my PZ27 factory carby from Pakistan, it was made in Japan .
( nice )

I also got a factory chrome muffler from Pakistan, it was an ATLAS HONDA product, I mentioned them before, I don't have a regular parts connection in Pakistan, I will go check those two closely .
( yeh the chrome one is popular here guys replace their new black exhaust with chrome one, chrome has a bit heaver sound )

Most of the CG125 internal parts as the same as the 1980's & 1990's CB125's as are the wheels, tires, chains & sprockets, clutch discs .
( yeh )

I only seem to find cheap Chinese dress up parts and I only want stock bits and bobs, Honda branded if possible .

Sadly the 125CC Motos are not popular here in the U.S.A., they're $1 sellers worldwide as they're reliable and keep running in severe duty even when poorly maintained.
( yeh in US a 125cc would be not enough to keep up with traffic or when you want to change lanes on highway but in streets it would be a pretty good option, can turn and cut easily, is lighter to maneuver. This machine was made to last with poor maintenance. The USA army used these CG125 , CBS 125 in Afghanistan war on rough mountains. Also Afghanistan people use them till date. The mountains their are rocks and very tough.
Here in Pakistan 125cc is enough becuase of crowed roads and jams. Even the highway speed is 100 km max. though you can do full meter 120 km with it.

My little red Honda close to 1,000 miles from home far into the Desert .
( must been a good time with a classic machine)
 

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Looked up ASV valve and what it does, not quite the same as an aircut. It is the equivalent of air injection on cars, air gets injected at the exhaust port to further burn incompletely burned exhaust to lower the HC amount. A leak in the small vacuum hose to the valve can idle you high if fuel can be picked up somewhere like a leaking idle mixture screw.

You can pull the valve by simply removing it and plugging all holes where things went.
 

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Looked up ASV valve and what it does, not quite the same as an aircut. It is the equivalent of air injection on cars, air gets injected at the exhaust port to further burn incompletely burned exhaust to lower the HC amount.
Thanks.
So is it is the same thing that virtually all Japanese machines imported to the USA have these days?
Yamaha calls theirs an "Air Induction System" (AIS).

S F
 

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@ XXX :

I find it very difficult to not enjoy riding any Motocycle anywhere unless it's raining .

Yes, Tiddlers run flat out in the Desert Canyons is fun fun fun .
 
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Well, it can be a switcher for additional air bleed like Honda, or the air injection thing. or I suppose there could be a standalone true decel valve which adds both air and fuel at a bit richer to stop popping at decel.
 

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Went looking again and the Yamaha AIS thing is more of the same as the Honda ASV, it injects air into exhaust at proper time to burn more completely anything going in exhaust.

The deal.............when you decel you lose the greater part of air and fuel to be very low and EFI typically kills injectors then to just pump air on cars. No fuel it doesn't ignite but a slight amount of fuel WILL ignite but slower burn to still be burning in exhaust. Emissions problem. You can do what the Honda aircut does, subtract one idle air bleed to richen up exhaust just enough to not pop (what a standalone decel valve does) or if no popping and high emissions only, you add more air to exhaust just to clean the exhaust up. Or you can add fuel to burn at decel AND air in exhaust to clean that up too, Several ways to do what the engines demand to be cleaned up. Exhaust can pop with just the right amount of fuel, too little fuel or too much depending on conditions often stops it. But you have to treat too much fuel as it is unburned HC. You afterburn by adding air to the exhaust, it burns in pipe more and can be done with a physical pump like cars used or pulse air which uses reeds to work the high and low pressures the exhaust pulses create in the exhaust manifold. Pulse air works well on 4 cylinder engines and even crank pulse twins but mostly at lower rpm when the reeds can open up more fully for longer. Lots of cars use it now too.

You need the exhaust well burned of HC, CO, and NOx ahead of time; it greatly lowers the load and temperature of the catalytic converter, which is actully made to live longest when it only has to treat a small amount of leftover emissions after most have been pretreated.
 

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Discussion Starter · #30 ·
Looked up ASV valve and what it does, not quite the same as an aircut. It is the equivalent of air injection on cars, air gets injected at the exhaust port to further burn incompletely burned exhaust to lower the HC amount. A leak in the small vacuum hose to the valve can idle you high if fuel can be picked up somewhere like a leaking idle mixture screw.

You can pull the valve by simply removing it and plugging all holes where things went.
Yeh Sorry i have been writing ASV but infect in carburetor its Air Cut Off Valve. I forgot the name Thanks
 

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Discussion Starter · #31 · (Edited)
Thanks.
So is it is the same thing that virtually all Japanese machines imported to the USA have these days?
Yamaha calls theirs an "Air Induction System" (AIS).

S F
It is also Called Euro 2 Standard bec in my country this cg125 in named by Atlas honda as Euro 2. Earlier version was Euro 1 about 7 years ago and before that no euro. Its pretty cheap to built. Euro 3 standard i think will recirculate exhaust. Combined braking system etc...

All new bykes being Manufactured in Pakistan have Euro 2 standard. I also have a Yamaha YBR 125 Carb version with exactly same device.
 

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Discussion Starter · #32 ·
ASV Air suction valve adds air to Exhaust to lower the exhaust temperature so the gasses do not decompose any further bec of temperature. Its a seperate device attached. It has 3 pipes. One connected to airbox. Second to intake mainfoild on engine intake side. Third to cylinder head to exhaust port outside.

Air Cutoff Valve is inside carb consist of a rubber diaphragm attached with turn on/off piston. on hard deceleration when throttle is fully closed it opens a fuel port to add enough fuel in mixture to avoided popping sound from exhaust.
 

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Discussion Starter · #33 · (Edited)
So Today i inserted the Air Mixture rubber O-ring and washer tested and nothing was changed. Now i believe that the problem is with Air Cutoff Valve Diaphragm bec i saw a tiny tear in it size of a needle. So fuel is being sucked from their.
To test this theory Today when i go home i will temporarily fix it or delete it and then test.
 

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I'm not sure you fully grasp how any A.I.R. / A.I.S. system works .

The fresh air introduced causes the unburned hydrocarbons exiting the engine to burn right there instead of collecting downstream inside the muffler where they can combust and make popping sounds , this increases the exhaust temperatures , not decreases them .

AMC in post # 29 explains this very well, I wonder if he perhaps had exhaust emissions testing training as did I long ago .

In any case, the ruptured diaphragm needs to be fixed before any conclusions are made .

It's interesting to note that carefully metered fresh air into the exhaust port will reduce emissions and eliminate popping where as an exhaust manifold / head pipe to cylinder head leak will allow un metered air into the hot exhaust stream and cause that pesky trailing throttle popping .

A.I.R is a simple and very effective method of cleaning up H.C. emissions on older design engines that use carbys .

I'm keen to see how this all works out, I began riding on a 50CC Honda Cub and went full circle, in time I rode Harley's and even helped set a world's record on one in 1976 but never quite lost that initial love of Tiddlers and love riding my CB125S (e) anywhere and every where .

You cannot impress anyone riding Tiddlers ~ it's all for your enjoyment as Motocycling should be .
 
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Discussion Starter · #37 ·
Recap: Byke was running even mixture screw was fully tight. The spark plug came out totally covered in black dust.

ok, Initially i thought that may be some fuel is leaking through the Air cut of valve circuit so i blocked the high suction passage which went to the outlet side of the carb (intake side of engine).

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here i placed a rubber to block it.
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showing where it went to the intake mainfold
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Here is the intake passage of air cut of valve on the other side of carb which is connected to the air filter side.
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To test if Air cut of valve is sucking air from this passage i blocked it with finger and engine gradually died so i know that it is working and air is passing through it.

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After doing these things i tighten the mixture screw again and the byke was still running on fully tight screw.
I also replaced the ideal get but for no good.

Than i reassembled the carb.

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Discussion Starter · #39 · (Edited)
I will run the bike and check if its making the plug black or not, if the plug will be perfect tan than i will run it with same carb regardless of mixture screw. if plug black than i will use the other carb that i bought 4 years before for some project. It dont have ACV system. its also for CG125 model 2002 and before

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Pic when it was bought and my first tour of 150km round trip. I still remember my loved ones :)

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