Life with a Chinese Carburetor (18 Viewers)

Joined
Dec 18, 2012
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Cuenca, Ecuador
Three months and nearly four thousand miles and it is still, well, Chinese. What a piece of junk. I have had this carburetor off at least fifteen times. Never worked from the get go. In Mid-May I did try it on the old F motor, 1 bbl carburetor, just to make sure I had everything sorted before the car went in to have the "new" 2F motor installed. Fuel level was good, required a minor idle adjustment, seemed fine. Took it off and put the 1 bbl back on. When I went to pick up The Beast with the new motor it was sitting there idling, but the mechanic told me the carburetor was not working right, fuel plunger wasn't squirting. I lived with it for a couple of weeks while sorting out other things with the car and the installation, like flexible connector from the header to the tailpipe stuff. Picked up a kit, nice kit, made in Japan, and replaced the fuel plunger and squirted carb cleaner through the ports on the body and top of carburetor. I did not separate the bottom two pieces as it seemed fine on the highway, just didn't start good or pick up when leaving a stop. Worked fine for two weeks and started acting up again. Went to the Toyota parts man I use mostly (got the kit from another Toyota parts place, it is way different down here) and he had a fuel plunger, wasn't new, I bought it. Tried it, no change. Over the next couple of months I lived with it, choke required hot or cold to start, flutter the gas pedal to get it up on the mains to go, real aggravating when you live where there are many vertical stop lights.

Fed up I took the top off, again, cleaned things out, seems to be pumping okay. Spilled the fuel out of the bowl into a clean container and see a little black spot. Flush everything again and put it back on the car. Now it is way rich, idles but like crap, runs like crap up high as well. Got a whopping 5.4 miles per gallon on that tank, you could practically see the gauge drop as I drove. Off it comes again this morning, this time completely apart. Can't say I really found anything "major." I did note that the isolator gaskets are not bonded to isolator like Aisan. They were spot glued and I feared vacuum leak so I used a razor blade to cut through the glue spots. Cleaned up and ready to put back together the way they came off and I note that they are not quite symmetrical, they only go on one way, opposite of how they were installed. The way they were installed the holes that feed the vacuum curved circuits were partially or completely blocked off. The long slow jets up by the venturis don't have numbers and without a set of pin gauges I have no idea what size they are so I installed the ones out of the kit which are stamped 65 and 90 into their respective bores. Put it back on and it idles, pops a little when hitting the gas, time to go get the dogs from the vet. Pulling up hills it starts off and then falls on its face. Onto the highway, same thing. Once settled into my normal 40-45 mph it is smooth. Doesn't die at a stop. Requires a little choke and crossed fingers to start but settles right into a nice idle.

The really aggravating part is that my mechanic had told me an Aisan carburetor was hard to find and cost $800. When I stopped by the other Toyota place for another kit (I have the old Aisan carburetor complete with frozen throttle shafts) he drops a brand new Aisan on the counter. How much I ask, $390! I was immediately sick to my stomach. While the Chinese copy was only $315, it was $445 when it got to me down here. The bottom line is that made in China is like buying a carburetor from Harbor Freight.
 

myquestoyota

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Wow, that sucks big time. Maybe I'm just lucky but my trollhole carb runs incredibly well. My cruiser has never run this well. Have a year on it maybe. Hope you get it sorted out.
 
Joined
Dec 18, 2012
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Cuenca, Ecuador
I have commented that I'm aware I may have gotten the 1 out of 100 that is bad, but I got it. I'll give you an example. I removed the bowl plugs to access the high altitude jets (I'm at 8,440 ft). When I unscrew them, both of them, I pull material out of the thread bores! I swap the jets, clean off the plugs and inside the holes and screw them back in. Of course it immediately leaks. The aluminum washers are something akin to 2024-0 material, very soft. I pull the plugs out of this old Aisan and they are copper. I wrapped the new plugs with yellow teflon tape, install the copper washers, no leaks and pray that I never have to take them out again. I rode motorcycles for 48 years, the last 22 on a daily basis. One bike, a 1999 model, instructed that I change the oil drain washer with every change. The dealer wanted $4.25 for a washer. I turned around to my Jet lathe and grabbed a rod of 6061-T6 I had and spun four washers. I was religious about my oil changes at 3,000 miles. Four years later I sold the bike at 68,000 miles and gave the guy three washers and the one in it was still sealing just fine. I think this is a case where bean counters prevail. It doesn't have anything to do with cost point to the consumer. It has to do with cost point for the manufacturer and saving a few pennies on a material change "justifies" itself. The bodies of these carburetors are cast and specifying a cheaper material will meet that cost point, but the consumer gets the cheaper product.
 

Racer65

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I would question anybody who claims to sell a new Aisin carburetor, let alone a new Aisin for $390.

Where did you buy the Chinese carburetor for $315 plus shipping? These carbs are all over eBay for half that much, shipped.

If I buy such a carb, I would not try to take it apart and swap in parts from a Japanese carburetor. It would be way better to rebuild the original carburetor.
 
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Joined
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I saw the carburetor, held it in my hands, it is identical to the one that came with the 1983 engine I bought in May. It is possible that the carburetor has been for sale for a long time and he just wants it gone. Not sure, but it is an Aisan, stamped, model tag intact, etc. I am going to try a jet change tomorrow and see if I can't get this thing to stabilize and provide good performance.
 

Racer65

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Sorry I just noticed you are not in the United States. I suppose it's possible some old stock is still available in your country. A NOS '83 Aisin carb would be very sweet.
 
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Hey Pin Head, I've been meaning to thank you for the videos. I wanted to comment that I would suggest that if you do some more to include a thorough examination and setting of the throttle butterflies. The FSM uses a SST that looks like a protractor. This tool could certainly be used to document what the setting is as well as for checking to correct specification. I realize this tool could be used on a variety of Toyota carburetors but what I figured out to do was fabricate two gauges using my conventional protractor head to control (in my case 24* & 67*) the two positions specified. I noted in one of your videos that when the hammer starts to open the secondary it was quite a bit more open than the specification for my carburetor. But, your videos certainly were a help. Without Berryman carb cleaner or an air compressor I had to resort to FSM direction of soaking in gasoline and then blowing things out with carb cleaner aerosol. I have been looking at air compressors and unit I like the best (of what is available) is a 4 hp 30 liter tank with wheels and a handle but it costs $700. Everything else is either 2 or 3 hp with tanks from 2 gallons to the tall stand up units that can't be moved around readily. Those tall units, with only 3 hp motors are $1,800. Just nuts on the prices.

Racer 65: I think you are echoing what I am feeling, NOS, good price, great carb. Might just have to spring for it. Of course my hesitation is that it is halfway to the air compressor!
 
Joined
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It is harder that I thought to work with your hands and run your mouth at the same time, so I don't anticipate doing any more carb videos. I mentioned in the videos that the FSM has an angle specification for the secondary, but I didn't say what it is because it varies depending on which carb you have. I just measured the opening of the one I was working on, which is a reasonable approximation for people that don't have an FSM. Many people find that their vacuum secondary won't open at all using the FSM spec and it requires more mechanical opening to get it to kick in. I think it is better to empirically determine how much mechanical opening it takes to get it to kick in. It is worth mentioning that if you increase the angle too much, it will not close all the way and will cause it to idle at higher RPMs.
 

Stumpalama

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I tried my hand at rebuilding one of these CHICOM carbs for a club member. Everything seemed to go together fine, but when installed by an experienced Cruiser mechanic, it would not meter correctly and dumped fuel out of the horn and nothing he tried would correct the issue. I thought I may have screwed something up, but then I supplied a stock carb I also rebuilt and it ran like a top. It seems nothing beats even an old stocker.
 
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erie pa
you would think by now people would not buy anything from china ,the stuff mostly doesnt work and is dangerous and has safety issues .there are way to many issues with the junk they sell .it amazes me how many people will replace the china stuff several times or take it back for warranty .im used to having stuff for 20 or 30 years before i have to replace it .i do have some china stuff but when i find usa stuff at an auction the china stuff goes to scrap where it belongs
 
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Pin Head I can identify with what you are saying as well as Stumpalama and Shelfboy. I did finally achieve success adjusting the cable throttle bracket to fully open the primary and saw that the paperclip had moved. That was when it was incredibly rich and I haven't checked yet this morning. After errands I will take a look at some re-jetting of the mains. Maybe later I will look over the old Aisan carburetor. I don't think it is a 1983 and didn't come with the motor originally. The guy had said the carb was rebuilt, and it had been at some point, but the secondary throttle shaft was pretty rusted and both butterflies exhibited some bb shots. I did get it all apart after soaking, and re-staked the screw threads. This carburetor has the single/double ring venturis and FJ40Jim indicates that went away in 1977.
 
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The chances of your carb being rich are slim as long as the choke is open. It is hard to know if it is rich because it can be very rich and run perfectly the same. You can't smell rich either. If you smell fuel, it is misfiring.
 
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Late this afternoon I was able to mess with the carburetor again. Not sure how anyone can remove and reinstall jets through the float bowl plugs. I couldn't so I pulled the top off so I could see what I was doing. Of course the jets had no markings on them. I had immediately swapped out the installed ones for the high altitude jets before ever trying the carburetor. Took them all to the shop for comparison. Without pin gauges I used the highly accurate toothpick and pencil test. The kit jets were 132 and 220 and were larger than anything that came with the carburetor, so I stuck them in, put it back together and took it for a ride. This jet change was substantial and I noticed no difference whatsoever. It is still idling fine but under acceleration it surges. Once leveled out it is smooth, it just doesn't respond well at all. Perhaps tomorrow I will install a new set of plugs, cap and rotor. Ballast resistor is cracked but still checking .7/.8 ohms. Voltage to the coil checks just over 9 volts.
 
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When you deviate from OEM, you will pay--usually, the further from OEM the more--

Aisans are available here on MUD--<$100, a good carb kit is $60. Rebuild and you will have minimal problems-(and you will know your carb-inside and out)-ones that MUD members can solve in minutes--
 
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The circumstances surrounding the "surging" aren't clear. just off idle? Wide open throttle? What is going on?
 
Joined
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Contact Mark at Marks offroad in Burbank, Ca. He is the man with toyota carbs. Tell him your situation and follow his recommendation and expertise.
Good luck.
 

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