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Discussion Starter · #1 ·
So I have had several issues that Ive chased down but there one that I can’t seem to figure out. A little back story, the guy that gave me the bike had recently purchased a new carb but also had purchased a kit for the old carb. I elected to put the kit in the old one because the new one just seemed like Chinese junk. It would run but run like crap on hot days. The choke would do nothing. It acted sort of like it was choked all the time. Fouling spark plug and what not. So I found the old choke assembly and reinstalled it. When I pulled the new plunger to the old one, the new one didn’t have a boring on the end which I noticed in the manual it was supposed to. So I took the old plunger and boot and reinstalled it. Now the choke it definitely doing something! It will only run full choke, it will immediately die if you unchoke it. I’m almost certain the jets are not clogged so is it possible the jets are wrong size?


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Not enough details or pics to make any determination.

Confusion: So I found the old choke assembly and reinstalled it. When I pulled the new plunger to the old one, the new one didn’t have a boring on the end which I noticed in the manual it was supposed to. So I took the old plunger and boot and reinstalled it.

The carb does not have a choke, but a 'by pass starter valve' - works like a choke, but opposite in function - a 'choke' chokes off air in order to enrich the air/fuel mixture for easier cold starts - the by pass starter opens a passage bypassing the throttle valve - this passage also has a fuel circuit - opening the passage (pulling the plunger off it's seat) provides a fuel rich mixture along with volume of air resulting in a fast idle without having to open the throttle.

You should not mix parts from one brand of carb to another.

Now if the engine dies as soon as the bypass valve is closed, it means the carb is clogged - not necessarily just the jets, but the internal air and fuel passages as well. The carb needs a complete disassembly and thorough cleaning in a commercial heated sonic carburetor cleaning unit.

Most modern dealerships have one for cleaning not only carbs, but other critical white metal parts including throttle bodies and fuel injectors.
 

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Discussion Starter · #3 ·
Not enough details or pics to make any determination.

Confusion: So I found the old choke assembly and reinstalled it. When I pulled the new plunger to the old one, the new one didn’t have a boring on the end which I noticed in the manual it was supposed to. So I took the old plunger and boot and reinstalled it.

The carb does not have a choke, but a 'by pass starter valve' - works like a choke, but opposite in function - a 'choke' chokes off air in order to enrich the air/fuel mixture for easier cold starts - the by pass starter opens a passage bypassing the throttle valve - this passage also has a fuel circuit - opening the passage (pulling the plunger off it's seat) provides a fuel rich mixture along with volume of air resulting in a fast idle without having to open the throttle.

You should not mix parts from one brand of carb to another.

Now if the engine dies as soon as the bypass valve is closed, it means the carb is clogged - not necessarily just the jets, but the internal air and fuel passages as well. The carb needs a complete disassembly and thorough cleaning in a commercial heated sonic carburetor cleaning unit.

Most modern dealerships have one for cleaning not only carbs, but other critical white metal parts including throttle bodies and fuel injectors.
The mixture of parts is from the previous owner. He couldn’t get it to run so he bought a carb kit that I have no idea if it was the right one but he gave me the old parts as well which I have reinstalled all of them back into the old carb because the problem was not the carb is was something else which I replaced. But yes the bike runs great for a while full choke but when not choked it dies immediately. So there is possible for it to be clogged even after it’s been thoroughly cleaned? I have a sonic cleaning unit I could put some kind of carb cleaner in along with the carb just to see and make sure alll the jets are clean? I’ll let you know if this works. Thanks as always for your help


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If you want an outstanding clean of the carb, go on Amazon and get some Master Solutions Master Stages 2020 cleaning solution - mix it 10% with distilled water in your sonic cleaner and heat to about 180 degrees - you will be amazed with the results.
 

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Discussion Starter · #5 ·
If you want an outstanding clean of the carb, go on Amazon and get some Master Solutions Master Stages 2020 cleaning solution - mix it 10% with distilled water in your sonic cleaner and heat to about 180 degrees - you will be amazed with the results.
Cleaned the carb the best I could and blew through every passage with cleaner and noticed nothing plugged. Will try it later. One question I had is the o-ring that goes on the enrichment valve end(choke) is flattened out. Do you happen to know the dash size of that o-ring? Also when I install the o-ring, should I install it in the groove in the carburetor or in the enrichment valve groove it self


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There is no o-ring in the enrichener plunger - there is an inlaid rubber seal that is supposed to be flat and seals against the flat boss at the end of the plunger well. If the rubber is damaged or missing, you simply get a new plunger or plunger kit.

Here's a couple of pics of an old, but good plunger
4678
4679
 

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Discussion Starter · #7 ·
There is no o-ring in the enrichener plunger - there is an inlaid rubber seal that is supposed to be flat and seals against the flat boss at the end of the plunger well. If the rubber is damaged or missing, you simply get a new plunger or plunger kit.

Here's a couple of pics of an old, but good plunger
View attachment 4678 View attachment 4679
The whole for the valve in not flat it has an o-ring groove at the bottom


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Discussion Starter · #8 ·
There is no o-ring in the enrichener plunger - there is an inlaid rubber seal that is supposed to be flat and seals against the flat boss at the end of the plunger well. If the rubber is damaged or missing, you simply get a new plunger or plunger kit.

Here's a couple of pics of an old, but good plunger
View attachment 4678 View attachment 4679



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That shiny spot with a hole in the middle is the seat the plunger seals against - the hole is where the fuel comes through - based on the pic, the carb is in serious need of a thorough cleaning.

Here's what Honda depicts - there is an o-ring in a groove around the middle of the plunger) - the seat is flat inlaid rubber (pic is from the service manual
4682
 

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Discussion Starter · #10 ·
That shiny spot with a hole in the middle is the seat the plunger seals against - the hole is where the fuel comes through - based on the pic, the carb is in serious need of a thorough cleaning.

Here's what Honda depicts - there is an o-ring in a groove around the middle of the plunger) - the seat is flat inlaid rubber (pic is from the service manual
View attachment 4682
The outer seal was rotted and cracked so I had to scrape it out to replace the seal, which is why it looks so rough. The carb is very clean now. Just have to get it home and install to see if I did any good.


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Discussion Starter · #11 ·
That shiny spot with a hole in the middle is the seat the plunger seals against - the hole is where the fuel comes through - based on the pic, the carb is in serious need of a thorough cleaning.

Here's what Honda depicts - there is an o-ring in a groove around the middle of the plunger) - the seat is flat inlaid rubber (pic is from the service manual
View attachment 4682
Here to reply that it’s running fantastic after setting the idle air screw and throttle adjustment according to the service manual. I guess there was something in the carb thanks so much as always


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