Running higher octane fuel in cheap Chinese motors

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Sailorman
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Re: Running higher octane fuel in cheap Chinese motors

Post by Sailorman »

Bottom line is the fuel in Cambodia is filthy. It makes no difference if it picked up that dirt in the ship bringing it here, in the truck transporting it, the petrol stations tanks or the rust inside your tank because you don't keep it full.(condensation) There is little or no consideration to purity in fuel here. In the states, the local government sends around trucks with a wide range of testing equipment to ensure purity and weight/volume. Your first line of defense are good fuel filters, second is carby/injector cleaners (some are a scam) and third, keep your tank as full as possible.

Even in America with all the testing there is dirt. I've gone into massive, emptied ships fuel tanks during shipyard periods and the floor looked like a sandy beach. Also there are organisms that grow in diesel fuel. On ships we used chemicals such as Biobor and Killem to kill these organisms, but still got our massive filter system clogged with them. We had big spinning things (centrifuge) called fuel-oil purifiers that took at most of the dirt, then through small micron filters. Your bike/car not performing up to par, you've got dirt in your carby/jet/float-bowl or your fuel injector(s) are clogged and instead of sending out a fine spray are sending out a dribble that does not combust well.
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juansweetpotato
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Re: Running higher octane fuel in cheap Chinese motors

Post by juansweetpotato »

AE86 wrote:The float bowls aren't adjustable on the Waves if I remember correctly. Either or, the easiest way is to get a complete rebuild kit (PZ carburetors are easy as pie to rebuild, so if you can get the float needle replaced, you can rebuild the whole thing), or to just get a new carby. New Viet/Thai carbies are around $60 I believe but I don't know of their availability in Cambodia. Rebuild kits likewise.

If you have a decent shipping connection, the carby is a Keihin PZ19 (usually, unless you have a Wave 125, and then I don't know).

Also, if you don't really care to set any of that up, you can pick up a Chinese copy carby for $10-12 at Russian market and just bolt it on. 99% of the time they work right out of the box just fine. The only thing I've had issues with a few of them on is the idle set screw, so I notch the idle screw with a knife and notch the washer and spring so it wont slip.
Cheers. Couple of things spring to mind. Won't the cheap Chinese carbs offer lousy fuel consumption? Carbs are like the brain of the bike aren't they? And why on earth would an 8 yo carb need any replacement! I've had it apart twice now and it's very clean inside. In Vietnam you can buy dif carb copies for the Wave from $5 up to $300 or so for the Japanese originals.
Can't get a carb replacement kit from Honda here. May be worth trying a float from a cheap Chinese carb . Any idea if they can be removed and if they will fit in the Honda carb?

When I blow through the float chamber needle hole with the float in up position (by hand) seal is good. It's just that the float is sitting too low when the chamber is full. It is a problem that has developed after about 12 months of owning the bike.
$60 for a new carb ! It would take me about 3 years to go through that sort of fuel from the leak. See the quandary?
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AE86
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Re: Running higher octane fuel in cheap Chinese motors

Post by AE86 »

It's all really down to the "annoyance" factor of ownership of cheap bikes, as I put it. The carby really doesn't need replacing at all and likely wont need replacement for years to come. It's just going to keep leaking until you get fed up with it and toss it in the bin for something else. Sure it's annoying, and honestly, that's something that always drove me nuts about SE Asian motorcycles, is because there were always a million little faults and niggles I could point out and would then spend hours on a solution to "fix". It's a far cry from the reliability we've grown accustomed to with cars and such, but it's life.

In regards to fuel consumption, I actually found that my Chinese carbies offered comparable fuel economy to their Japanese counterparts. I make use of them all the time when tuning my bikes for modification because they're so cheap, so I can safely say that most are practically the same in that regard. Floats and needles SHOULD be interchangeable, but the Chinese haven't really got the idea of a standardized part system, so often times it's hit and miss. Might work, might not, it's a crap shoot.

Where is the fuel coming from? Are you sure it's a float problem, or is it coming from one of the "breather" pipes off of the carby? A lot of Mikunis and Keihins will leak a trace amount, even when new, and if it's just a smell of petrol you're encountering, it's likely normal, especially if you're getting decent fuel economy.
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juansweetpotato
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Re: Running higher octane fuel in cheap Chinese motors

Post by juansweetpotato »

AE86 wrote:

Where is the fuel coming from? Are you sure it's a float problem, or is it coming from one of the "breather" pipes off of the carby? A lot of Mikunis and Keihins will leak a trace amount, even when new, and if it's just a smell of petrol you're encountering, it's likely normal, especially if you're getting decent fuel economy.
Thanks for that. Interesting. The fuel is coming from the float overflow pipe. Not just a smell, but almost. It evaporates in this heat pretty quickly. I may just try a cheap Chinese carb if you think the fuel econ will be good as the orig. What are the downsides to the cheap carbs? Why are Honda ones so much more expensive? Once again, it is a problem that has developed not a manufacturing from the factory problem. Got me scratching my head.
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Sailorman
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Re: Running higher octane fuel in cheap Chinese motors

Post by Sailorman »

The needle on your carb float bowl/chamber is either worn or defective, or your float isn't set properly. The float push's up on a pointed piece of usually brass (needle may have a rubber tip) and when the float gets pushed up enough by fuel filling the bowl/chamber the needle is pushed up and stops the flow of fuel. If it doesn't stop the flow you get overflow out the overflow pipe. With the vibration of a motorcycle its not uncommon for the rubber point on the float needle to get worn and leak. Its a cheap fix.

BTW/ Honda for its small engines subcontracts a lot of its parts from China, but they say Honda and Japan on them. Case in point: In the US I had a Chinese gas generator and the carb said Japan on it. Engine was a double for a Honda one lunger.
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AE86
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Re: Running higher octane fuel in cheap Chinese motors

Post by AE86 »

^^Don't put it passed the Chinese to stamp "Japan" on their carbies. Half of my Chinese carbies have "Made in Japan" on them, but they're clearly not genuine Keihins or Mikunis. You're right in saying though that Honda subcontracts a lot of it's work out to China, lit everyone pretty much. The entire GX and GC engine series I believe comes entirely from there.

Quality is often in the castings and the lack of "workmanship" that goes into making a nice and relatively trouble free carby. I am unsure of long term durability but I have a 30 year old Keihin and almost 100,000 miles on my everyday Cub and it's still fine. It's been rebuilt a few times (worn needle and jet), but only recently as the actual bore seemed to wear passed the point of being useful.

While I am unsure of which carby is on your Wave, I'd just venture to guess that the float seat (the area where the float needle (rubber tipped on most small Keihins) has some minute junk on it so it's causing a tiny amount of leakage, but not a huge amount. A good clean out with proper carb cleaner would benefit you either way, but that's more of a guess than not.
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