Bad Gas?

1969 CL350

1969 CL350

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Late last fall, I was headed home from a ride on my ‘69 CL350 and stopped at a gas station about 4.5 miles from the house to fill up with some non-ethanol. A few blocks from home, the bike bogged really badly and wouldn’t accept hardly any throttle above idle. It kept running and would idle just fine, though, and I managed to limp on home. I took the plugs out and they were really black, much darker than my usual too-rich midrange condition I’ve been battling for years. I checked the battery voltage and it was well over 12 volts. Disgusted, I parked it, and wasn’t motivated to look at it again until this past Saturday.

I drained the tank through the petcock, and the gas didn’t have as strong of a gas smell as I would expect. I took the air cleaners and carbs off and haven’t had a chance to take them apart yet. I suspect everything will look fine in there, too, since both cylinders were afflicted at the same time. I also checked all the connections to the coils and condenser, which are all fairly new, and the plugs do spark when cranking. While I was thinking about what might have caused the problem, I ordered a couple smaller midrange jets for the carbs and will install them when they arrive.

If the carbs are fine inside, I’m thinking about just putting everything back together with new plugs and the smaller jets and trying some new gas to see if that’s the cure. What do y’all think? Does that sound like something that could be caused by bad gas, or do I need to check other things first?

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I think there is a Taco Bell joke somewhere in that title! :D There are sometimes issues with water or other contaminants in there. My friends modern Yamaha FI bike got a bad batch last fall for his winter layup. Took a tank draining and fresh fuel to fix the issue this spring.
 
Fuel contamination seems possible to me. If there was water or something in the fuel, maybe the idle circuit was somehow acting as a filter or otherwise mitigating the effect of the contaminant(s).

If the fouling were the root cause, I don't think it would have continued to idle.

I would try fresh fuel and go from there.
 
Yeah, I’ve never had a bad gas problem in all the years I’ve been riding, so I don’t know how that affects the running. The normal idle doesn’t seem to make sense, though.
 
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I would think that too much water would mean a non-combustible mixture, which could explain bogging. If the idle jet could somehow scavenge the lighter gas from the top of the bowl, maybe it would explain the steady idle.

Another odd possibility could be a gas cap venting issue that arose at the time you filled up. Unlikely and I have no idea how that would pop up spontaneously.
 
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stl360+450 said:
I would think that too much water would mean a non-combustible mixture, which could explain bogging. If the idle jet could somehow scavenge the lighter gas from the top of the bowl, maybe it would explain the steady idle.

Another odd possibility could be a has cap venting issue that arose at the time you filled up. Unlikely and I have no idea how that would pop up spontaneously.
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Yeah, I took the cap off when it happened and it made no difference. When I drained the tank, I did most of it on the bike by running the hoses from the petcock into a funnel to a gas can. The gas flowed fine through the petcock in “ON” and “RES”, so there’s no obstruction in the petcock either.
 
Pour some of the gas out into a glass jar. Let it sit overnight and you’ll see the water layer form on the bottom.

Water also is 40% denser than gasoline - it’ll clog those jets right up when you go to force more through.
 
EzPete said:
Pour some of the gas out into a glass jar. Let it sit overnight and you’ll see the water layer form on the bottom.

Water also is 40% denser than gasoline - it’ll clog those jets right up when you go to force more through.
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I will try that tomorrow. Of course, if there is water in the gas, it’s already settled in the bottom of the gas can, so I’ll shake it up before pouring some in a jar.
 
We had a case here years ago where the local refinery screwed up their formula and sent out bad gas that clogged fuel injectors. Engines would run but die at idle. Big mess!
 
stl360+450 said:
What came of this possible bad gas situation, Dale?
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No conclusion yet. I couldn’t really check the gas quality because there was already dirty gas in the can when I drained the tank. I have the carbs apart to check float levels, install some smaller intermediate jets, etc., but that’s about it. We’re having a lot of work done around the house and I can’t find the time right now to really get into it. Thanks for asking, though.
 
1969 CL350 said:
Late last fall, I was headed home from a ride on my ‘69 CL350 and stopped at a gas station about 4.5 miles from the house to fill up with some non-ethanol. A few blocks from home, the bike bogged really badly and wouldn’t accept hardly any throttle above idle. It kept running and would idle just fine, though, and I managed to limp on home. I took the plugs out and they were really black, much darker than my usual too-rich midrange condition I’ve been battling for years. I checked the battery voltage and it was well over 12 volts. Disgusted, I parked it, and wasn’t motivated to look at it again until this past Saturday.

I drained the tank through the petcock, and the gas didn’t have as strong of a gas smell as I would expect. I took the air cleaners and carbs off and haven’t had a chance to take them apart yet. I suspect everything will look fine in there, too, since both cylinders were afflicted at the same time. I also checked all the connections to the coils and condenser, which are all fairly new, and the plugs do spark when cranking. While I was thinking about what might have caused the problem, I ordered a couple smaller midrange jets for the carbs and will install them when they arrive.

If the carbs are fine inside, I’m thinking about just putting everything back together with new plugs and the smaller jets and trying some new gas to see if that’s the cure. What do y’all think? Does that sound like something that could be caused by bad gas, or do I need to check other things first?

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If you did actually get non ethanol fuel, there shouldn't be water as 100% gasoline and water will not mix. Also, most gasoline dispensers have water filters on them that will not pass water. Also, filters for gasoline are mandated 10 micron. Did the non-ethanol gas have a hose and nozzle dedicated to 100%, or is it shared with the blended products? We used water to clean underground storage tanks back in the day when they were going to start adding Ethanol to the fuel. As a guy that works in the fuel industry, I only buy fuel at Branded stations, that I know have good fuel tank monitoring.

Was the station an independent or a chain? I find chains have a better chance of quality fuel monitoring. I hope this helps, as you all know the bikes better than I do.

Larry
 
I had two bikes I was rebuilding, '73 CB750K and a Suzuki'79 GS1000E. I went to the local (CA) station and filled up a can, then the bikes. Didn't get back to work on them for a week or so, and both would hardly run, one worse than the other, due to the amount in their tanks before adding, I expect. I was workng on the carbs on both, always the final thing, and it hit me later that I put in the gas from the same station. A bottle of 'Heet' dry gas cured them.
 
ferrisbueller said:
If you did actually get non ethanol fuel, there shouldn't be water as 100% gasoline and water will not mix. Also, most gasoline dispensers have water filters on them that will not pass water. Also, filters for gasoline are mandated 10 micron. Did the non-ethanol gas have a hose and nozzle dedicated to 100%, or is it shared with the blended products? We used water to clean underground storage tanks back in the day when they were going to start adding Ethanol to the fuel. As a guy that works in the fuel industry, I only buy fuel at Branded stations, that I know have good fuel tank monitoring.

Was the station an independent or a chain? I find chains have a better chance of quality fuel monitoring. I hope this helps, as you all know the bikes better than I do.

Larry
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It was a CITGO station that I rarely patronize. The pump had two hoses, one for various grades of gas and one for diesel. The 87 octane button was marked Non Ethanol, but there’s no telling what I really got…lol. I had a similar problem with a different motorcycle at the Texaco station across the street from the CITGO years ago, and it was a separate pump dedicated to 93 octane non ethanol. I’d guess that there could be other pollutants in gas besides water. In any case, I’ve already cleaned out the gas tank and carbs, so when I put it back together with some fresh gas, I’ll know if it was the gas or another problem.
 
There was a chain of stations here that wanted to sell non-eth out of the same hose as e10, the state told him he could not as the customer could get a hose full of e10. He asked the state about a customer wanting 93 octane, but getting a hose full of 87 first. He won the right to sell non-eth out of the same hose. That is where imlearned of the term deminimus! He then bought new dispensers that had a separate hose for non-eth. I always buy from a separate hose. I hope that you just got some bad fuel, as that will be the easiest fix.

Larry
 
The carb innards look fine. Diaphragms are good, all passages and jets are clear, needle valves are working as they should, float levels are set at 28 mm now, and I’m installing slightly smaller midrange jets. I’ll check all the electrical connections under the tank before I put it all back together and dump some fresh gas in it. I’ll update this when I get around to doing that.

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Did you check gas for water or ethanol?
Small engine places or lawn service usually have kits because two stroke weed whackers, chainsaw, etc specify non-ethanol fuel
Do you usually get gas from same place or was it just convenient at the time?
Years ago, gas station few miles away delivered about 20,000 gallons of contaminated gas,tanker truck had been left at depot all weekend with open filling caps, gas floated out, water, almost half the tank.
Similar thing happened when I lived in Britain, except tanker truck got filled with sea water (that must have been deliberate sabotage?)
 
crazypj said:
Did you check gas for water or ethanol?
Small engine places or lawn service usually have kits because two stroke weed whackers, chainsaw, etc specify non-ethanol fuel
Do you usually get gas from same place or was it just convenient at the time?
Years ago, gas station few miles away delivered about 20,000 gallons of contaminated gas,tanker truck had been left at depot all weekend with open filling caps, gas floated out, water, almost half the tank.
Similar thing happened when I lived in Britain, except tanker truck got filled with sea water (that must have been deliberate sabotage?)
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No, I drained the tank into an old gas can with who knows what was still in it.
 
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