10% Ethanol

It was known that ethanol was good at raising octane ratings in gasoline before we had leaded gas. If they had just bit the bullet back in the 1920's (ethanol cost more to produce than other octane-raisers), we'd all be driving vehicles that were designed to handle ethanol, and we'd probably be getting the type of performance you can get out of E-85-only motors. But tetraethyllead was cheap to produce, and a money-maker for GM (who had the patent on using tetraethyllead) and Standard Oil (who had the patent for producing it). They partnered to form Ethyl corp, so that's what we ended up with for 50 years. We are only getting back to what we should have used in the first place. Unfortunately KZ riders are stuck with vehicles not designed to handle ethanol, so get out your tank liners, solder for fixing brass, and buy stock in Gumout.

Another issue I've had with old Kaws using alcohol diluted fuels is that the alcohol absorbs into the black foam carburetor floats, making them heavier which causes the fuel level in the float bowl to rise.
I'll admit that I don't know this for a fact, rather it's just a suspicion based in part on the fact that I've never encountered a KZ1300 where the problem was a too low fuel level. If I could get my hands on an actual NOS 1300 float I could perhaps prove it. In the 1300 community most restorers have gone to custom made brass floats to solve this issue.
Bill

That's strange. I haven't noticed that on any of the 550 or 400 floats. I've also worried about it, and thought by some miracle they were not affected. Probably wishful thinking, but so far so good.

I run enough miles that gumming has not been a problem due to ethanol. Performance and fuel economy are down ever so slightly.

My biggest complaint is that my vacuum operated fuel petcock starts leaking on an annual basis. The thin diaphragm rubber softens and cannot seal as it is sandwiched between the layers of the petcock. After putting new gaskets in every year for about 5 years, I finally got some thick fiber reinforced rubber material and removed the guts from the petcock. You can manually shut it off by turning the petcock handle, but otherwise it is always ON --- and with no reserve feature. Not good, but I got tired of fooling with the annual repairs.

And then the moisture absorption. The humidity is usually high where I live. Place a pan of gasoline out in the ambient air and it becomes cloudy within minutes. Which means that I am running my engine partly on water. Our guvment and Obummer watching over us with the ethanol fuels.

KZQ wrote: Another issue I've had with old Kaws using alcohol diluted fuels is that the alcohol absorbs into the black foam carburetor floats, making them heavier which causes the fuel level in the float bowl to rise.
I'll admit that I don't know this for a fact, rather it's just a suspicion based in part on the fact that I've never encountered a KZ1300 where the problem was a too low fuel level. If I could get my hands on an actual NOS 1300 float I could perhaps prove it. In the 1300 community most restorers have gone to custom made brass floats to solve this issue.
Bill

If you have a really accurate scale such as a triple beam balance you could weight some floats before and after an oven bake. Gasoline may absorb into the float so not sure how you would figure out if the alcohol was to blame or just the gasoline.

As an aside, my car broke down one time when the fuel pump failed. It was an electrical pump in the gas tank. Ordered up a new pump and pulled the old one out but upon reinstall I found the large O-ring for the pump was swelled up and couldn't be refit as is. Scratched my head and decided to bake the old O-ring in the oven for a while. Low and behold, 1 hour at 170F and the O-ring shrunk down to normal size and I was able to reinstall the pump.

Nessism wrote:

KZQ wrote: Another issue I've had with old Kaws using alcohol diluted fuels is that the alcohol absorbs into the black foam carburetor floats, making them heavier which causes the fuel level in the float bowl to rise.
I'll admit that I don't know this for a fact, rather it's just a suspicion based in part on the fact that I've never encountered a KZ1300 where the problem was a too low fuel level. If I could get my hands on an actual NOS 1300 float I could perhaps prove it. In the 1300 community most restorers have gone to custom made brass floats to solve this issue.
Bill

If you have a really accurate scale such as a triple beam balance you could weight some floats before and after an oven bake. Gasoline may absorb into the float so not sure how you would figure out if the alcohol was to blame or just the gasoline.

As an aside, my car broke down one time when the fuel pump failed. It was an electrical pump in the gas tank. Ordered up a new pump and pulled the old one out but upon reinstall I found the large O-ring for the pump was swelled up and couldn't be refit as is. Scratched my head and decided to bake the old O-ring in the oven for a while. Low and behold, 1 hour at 170F and the O-ring shrunk down to normal size and I was able to reinstall the pump.

One way I could think of would be to weigh a couple of used floats. Bake them. Reweigh them to see if they lost anything and then submerge one in alcohol diluted fuel and the other in non-alcohol fuel. The question might end up on how long they'd have to be exposed to the alcohol to absorb enough to measure the difference.
Good idea there on the baking Nessism.
Bill

I'm using the floats from my 28's. I'll get a set of these in time.
Steve
jetsrus.com/individual_parts/002_501_su.html

Brass floats, so far, are the only ones I've seen disintegrating, usually in other brands, like Honda, which used brass floats in their Keihin carbs. I haven't seen any problem, yet, in Kz's using almost the same Keihin carbs, but with foam floats. Also, some of the other brass parts in 550 carbs are starting to show up in the forum as disintegrating, most notably the overflow tube. When it cracks, the carbs will never stop leaking. I'm not sure brass floats are a good idea. Alcohol is known to eat brass.

What brand carb does the Kz1300 use? Maybe Mikuni used a different type of foam?

The brass floats in my 30 year old 33's were worn out at the pivots. One was filling up with fuel. I tried soldering it but no luck. I put the foam ones in and am running them now. They're 40+ years old and still work. The only thing I had to do was bend the stop on them so they would allow more fuel.
Steve

Yeah, I'm not sure why some brass floats seem to just crumble, and some seem to work for years. Maybe the crumbling ones sat in ethanol for years, and some were drained for winter storage. Maybe different zinc content in the brass. Not sure. The crumbling ones I see mostly come out of old Honda 350's and 450's.

I suspect vibration. The brass float in my 69 F250 kept leaking. I'd solder it but it would fail again. I could hear it slapping the side of the tank if it was low. Ordered a new one a year ago, no issues.
Steve

nitrokeeb wrote: I've certainly seen a lot gummed up fuel systems. I teach Auto Tech, and we can have cars that can go for years on a full tank of gas. Pulling in and out of the building doesn't use much gas. Ive seen misfires caused by plugged injectors, and I've seen a Hemi Dodge Magnum bend the push rods because the valves gummed up and would not move. But no one ever had a good explanation as to how ethanol causes it. A 20 year old bottle of scotch doesn't seem to be affected after opening, and it's 40% ethanol.

I was at an automotive instructors trade show last month, and there was a booth from another college who had done a study on ethanol in fuel. They ran three generators for hundreds of hours. One one ethanol free, on on e10, and one on e85. Guess which was the cleanest? The e85 engine had almost no carbon.

We got into a discussion on ethanol in fuel causing gumming. They mentioned that they had the gasoline analyzed. It turns out the regular grade e10 was swill! But it wasn't the ethanol that was the problem.

While renewable fuels are a worthy goal, that is not the only reason ethanol is used. It oxygenates the fuel and boosts octane. It replaces things like MTBE. The fact that it raises octane means that the gas companies can use lesser base fuels and not worry about it knocking. They found premium fuel with 10% ethanol to be much better.

I'm not claiming that ethanol doesn't cause any issues, but it's an interesting conversation. I would be curious how much less problems would be caused if we ran "top tier" fuel though our delicate carburetor passages...

Top Tier

+1
Todays gasoline is formulated to have a short shelf life. Here in Nebraska E10 has been around since the 70's and was called Gasahol back then. It was a midgrade fuel at a 91 octane rating. Back then fuel storage was not a problem. I have had no storage problems with what little E85 I had sitting around for like a year. For the last couple of years we have been "blessed" with 87 octane E10 for our cheapest grade fuel along with regular 87 and 91. And Nebraska is not the middle of the corn belt. Iowa produces way more corn.


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