Fuel issues - ethanol and safety

[drhooves]

I found an older post that indicated octane doesn't seem to be too much of a concern.  But a couple of the local Casey's here in downstate Illinois recently quit supplying ethanol/alcohol free gas - which I prefer to put in the '86 R65 I own.  This is mostly to avoid water building up in the carbs.

Has anyone had issues related to using fuel with ethanol?

The other problem I've experienced after dropping the bike on its left side - fuel was pouring out of the upper (right side) petcock after I fell - with the engine still running.  There were a few moments of concern as to whether to hit the kill switch, pick up the bike, or run like hell.

Is this a basic flaw in the gas tank design?  Seems crazy not to take into account a  bike being laid down.  Everything seems snug as far as hoses go - not sure if this is just my bike, or all R65s.... :-?

[Luca]

The main problem with ethanol is it sucks for long term storage.  If you are riding you bike with some frequency and don't have original rubber components you should be fine.  Storage is also important.  If your bike is garaged you will have far less problems than if it lives outside or in a humid environment.

As far as I know the R65 only has a left hand fuel valve  :-?

[Bob_Roller]

I started using fuel containing ethanol in 1973, I lived in the Chicago area and it was all you could get .
Other than a short spell where MTBE was added to the fuel here in the Phoenix area sometime in the later '90's .
Never had a fuel issue with ethanol, unless you let the vehicle sit for an extended time frame, then you will have problems .

[drhooves]

...  Storage is also important.  If your bike is garaged you will have far less problems than if it lives outside or in a humid environment.

As far as I know the R65 only has a left hand fuel valve  :-?

The bike is all original equipment from what I can tell, except for the tires, oil and the fuel lines I recently replaced.  I do keep it in a garage, and I believe it's been garaged since new.  I'm supposedly the third owner, of the '86 R65 which I bought last September with just over 14,000 miles on it.  I've put about 3500 miles on it so far, but am a bit concerned about the ethanol on other parts that may be 34 years old.  It won't be left standing around much, though I can't put as many miles on it during the winter.

On pages 8 and 10 of the owners manual, there are pointers to the left and right fuel taps respectively, so I believe that's stock - and that's what my bike has.

[Barry]

Is this a basic flaw in the gas tank design?  Seems crazy not to take into account a  bike being laid down.  Everything seems snug as far as hoses go - not sure if this is just my bike, or all R65s..

R65's from 85 onwards have a different fuel tank to all the previous 78-84 R65's which had only one fuel tap on the left side.  You can expect fuel to leak when a bike is laid down but it's usually from the carbs rather than the fuel tap. There has to be something wrong with the tap connections for fuel to leak from that point and if the tap does leak it would also do so with the bike upright. Could it have received a knock as the bike fell.

[Kelvin]

My understanding (happy for someone with better recollection of high school chemistry to correct me) is that ethanol has both polar and non-polar solvent properties, so it can dissolve water (polar) and petrol (non-polar). Water won't dissolve in petrol because polar solvents don't dissolve in non-polar solvents, so if you have water in your petrol tank or carburettor and use non-ethanol fuel it hangs around and can cause corrosion. This happens particularly where it collects at the base of the fuel tank. If you use ethanol fuel it dissolves in the ethanol and transits harmlessly through the combustion chambers.

Decades ago I would expect to find small "bubbles" of water in the float chambers when I removed them. This doesn't happen with ethanol fuel.

The storage problem seems to be with ethanol fuels retaining the water and allowing corrosion over winter. However, I don't know why this would be more severe than using non-ethanol fuels and having the same amount of water sitting at the bottom of the tank.

Although ethanol has been suggested to rot rubber seals all my fuel hoses and carburettor O-rings have been replaced since the 1980s, and don't seem to be rotted. Normal running of the engine at operating temperature over 100 degrees Celsius should evaporate off any ethanol/petrol/water that has slipped past the piston rings. So there should be no contact between the ethanol fuel and the various engine seals.

[drhooves]

R65's from 85 onwards have a different fuel tank to all the previous 78-84 R65's which had only one fuel tap on the left side.  You can expect fuel to leak when a bike is laid down but it's usually from the carbs rather than the fuel tap. There has to be something wrong with the tap connections for fuel to leak from that point and if the tap does leak it would also do so with the bike upright. Could it have received a knock as the bike fell.

Ah, the fuel leak could have been from the carbs.  It's a goofy gas tank for sure, with a split design, and distribution of the fuel kept even by the maze of crossover hoses underneath the tank.  So laying on the left side at about a 45 degree angle, the fuel could have been leaking out of both carbs, and running down the crossover hose from the left side, and only appearing to be flowing out of the right petcock.

After falling, I scrambled over pretty quick when I noticed the fuel leaking with the engine running.  As I got to the bike, the engine died, but I hit the kill switch anyway and then picked the bike up and put it on the side stand.  Then I danced around for a few minutes, cursing, and kicking myself for not paying closer attention to the intersection and where gravel collects.  So I think the bike was only laying on its side for 8-10 seconds, and I don't think the petcocks were knocked around.

[Luca]

The storage problem seems to be with ethanol fuels retaining the water and allowing corrosion over winter. However, I don't know why this would be more severe than using non-ethanol fuels and having the same amount of water sitting at the bottom of the tank.

if enough water collects in ethanol laden gas, the water and ethanol precipitate out of solution in a process called phase separation.  That alcohol/water mix is highly corrosive and can really do a number on gas tanks and carburetors.

Gas with ethanol also seems to produce what somebody described to me as "gummy hydrocarbons."  I don't know the science, but I've seen plenty of the clear jelly clogging up the jets on small engines.  Almost looks like caviar

[drhooves]

Thanks for the replies, Gents.  My apologies for posting the question to begin with though - I didn't enter the search correctly when looking for ethanol, but with the timeframe of all posts, there's quite a few out there.  Lots of good opinions about ethanol resistance, difference in mileage, coated gas tanks, floats and jets, etc.

Since I believe pure gas will become more difficult to find, I went ahead and put 4 gallons of 10% ethanol E87 gas in the bike which nearly filled it up, and put 130 miles on it this afternoon.  No result on mileage yet, but there was a mix of results - the bike seemed a bit smoother at higher speeds, but it did idle with a faint bubbling, though still at 1100 RPM.  These results are not quantitative, and could just be my overactive imagination.

I'll have to read through more of the older posts, and see what other changes I may need to consider.  I've used fuel stabilizer in the past with no ill effects on bikes and lawn mowers.  I've used a bottle of Heet now and then to try and keep water out of the gas tank.  Hard to say what the results have been since I've moved back to warmer climates, but Heet was pretty much mandatory when I was living in northern Maine.  -25 to -30 F and a gas tank less than half full was a recipe for a fuel line freeze up.  Several times I had to add a bottle of Heet to the tank, then wait a half hour before starting my truck.  But it worked!  Then off to the gas station to fill up.

[Kelvin]

if enough water collects in ethanol laden gas, the water and ethanol precipitate out of solution in a process called phase separation.

Many thanks: with the name of the problem it was easy to do some research. So:

E10 will absorb about a tablespoon of water per gallon, any more than this and the phase separation happens, producing the corrosive mix. This shouldn't be a problem in my 20L tank where my main worry was droplets of water, less than a teaspoon, when I should be able to have 4 tablespoons before the phase separation occurs.

It is a major problem with marine applications, so may be worse if you live near the sea or park your bike in the rain.

E10 has reduced shelf life compared to straight petrol, like a month compared to a year, so it's more important to use a fuel stabilizer if you're not using the bike for a while. It's also more important to avoid E10 when you're concerned that the pump fuel is old.

There's a lot of literature about how ethanol rots fuel system components, particularly in old machines, but we have the benefit of simplicity by design: as long as we've replaced the fuel hoses and carburetor seals in the last 20 years they should be able to cope with the ethanol.

The ethanol can also dissolve plastic, which seems to account for various varnishes and glug in small engines where there are plastic components.

Ethanol fuel has been known to corrode carburetor parts, however my bing float chambers corroded in the 1980s, pre-E10, so I'm not sure that this is any worse than water.

While I'm running the bike regularly, every few weeks, I'm not expecting a problem and am optimistic that using ethanol fuel will remove any water that has crept into the tank. If I was laying up the bike I'd be really careful to use non-ethanol fuel and probably add a stabilizer.

[georgesgiralt]

Hello,
I live in France so take my comments accordingly. Your fuel is not the one I get. But we have E5 and E10 gas available.
I found that my R65 needed a little change in jetting, I've reduced the main jet from the 145 specified in 1982 by BMW to around 135~138.
I use mainly E5 which is 97 octane, our E10 being 95.
Of course, the way I use the bike is not the same now as it was in 1990 so the change in jetting could have many reasons other than fuel composition.

[Barry]

Georges,
 
It's interesting that you reduced the main jet size as fuel containing ethanol has a lower calorific value which would in theory require a larger jet.    Perhaps BMW over sized the main jets. 

[georgesgiralt]

Actually, I played a lot with the jetting (main and needle jets) and the needle position.
bear in mind I started with a 1982 version which had a big RT fairing for it's first 30 years of existence. She was hungry and ate a lot of fuel.
When I removed the fairing, I knew i had to change the jetting to get the mileage I was expecting. SO I started digging ...
So my results are based on a bike without the fairing and eating 5% Ethanol fuel.
I started to size the main jet, with the throttle wide open and inspecting the plugs after cutting the engine with the kill switch. This inspection is not easy with fuel containing ethanol...
Once the main jet is sizer properly, I played with the needle jet and needle position by asserting how the bike reacted to throttle transition from low speed/quite closed throttle to opening the throttle to 1/4, 1/2, and 3/4 open..... It took me days...
Now I'm happy with it. She is running very fine and react as fast as her age and power output allows !
Bear in mind that you need FIRST to have the engine set up perfectly (valves, timing, etc...) and the carburetors in pristine order and all rubber new. Do check the fuel flow before testing for the main jet size. If the bike starve, whatever size the main jet is, she won't run fine... And choose a road free of other vehicles and speed controlling cameras...
Have fun.

[dogshome]

I notice the jet sizes in my R65 (according to Haynes) are large 148. The needles also rich ones high in the piston. The later models (particularly USA) get smaller and needles lower presumably for emissions. 

My R65 get about 40MPG with RT fairing and cruising speed between 60 and 80 MPH depending on the road.

I just fitted an 860 kit and looking at Haynes, the 80s run similar jet sizes to the 65, with only the 100 needing something bigger (with a bigger choke). We shall see.

There is a big difference in crispness and starting by using a lead replacement / stabiliser. I also put a very small amount of 2T in occasionally as the tap gets quite stiff without that!

I replaced my fuel lines with Tygon (yellow) and put black electrical braid over them. The original rubber looked like a tea bag when you bent it. I think I've replaced most of the external rubber seals and parts apart from the brake lines now.

Also replaced the tap internals and the brass feed pipe successfully, but she has been known to spray me if i don't add a little 2T now and again. The cork carb gaskets are the worst designed part on the bike and I will cut some Viton to replace them soon! They come from the same age as rope or Lignum (wooden) bearings!