ethanol fuel - NC30 compatibility

[Maelstrom]

Well we better put our collective heads together because E10, or worse, is going to become the norm. In NSW Australia they were going to ban the sale of unleaded fuel in 2012. One poster sent me a pm about making the other rubber parts in the fuel system out of Viton. That could be done but I am not so sure about the fuel tap diaphragm because Viton is not as good in dynamic applications as NBR. Then the bike should be rejetted to run E10 as it would be too lean otherwise. Corrosion seems to be a big problem too and I do not have many ideas for that problem.

[AdrenalineJunky]

is the fuel tank fibreglass on the nc30?

[AdrenalineJunky]

There's a good info page on ethanol-blend fuels here: http://www.groups.tr-register.co.uk/wes ... pdate.html

I contacted Honda but their reply was rubbish:

Thank you for your recent e-mail to us.

At this stage, from speaking to my colleagues they have advised that most fuel in the USA is 10% ethanol blend or 15% MTBE All current USA spec motorcycles are compatible with these fuels. Unfortunately they are unable to advise the exact date of when these first became compatible. However, it has been for many years.

Unfortunately, this is the only information that we can obtain with regards to your query.

Thank you for taking the time to contact Honda (UK) regarding this matter.

Rubbish eh?

So I had a think and it seems that we will need to replace or modify the following things:

1) Fuel tank - it depends what it is made of. If fibreglass then it will almost certainly have to be replaced, or resealed/treated somehow. Many metals are also incompatible, including aluminium.

2) Rubber components in fuel system - as far as I know these are: hoses, fuel tank filler cap seal, seals and o-rings in fuel tap, seals/o-rings/gaskets in carbs... am I missing anything?

2) Carbs - carbs are usually made of an alloy of zinc and aluminium, whereas jets are typically made from brass. The metals are electrically dissimilar so can suffer galvanic corrosion if ethanol-blend fuels are used (more information). Therefore we are going to have to replace the jets, at the minimum. Possibly also the floats, depending on what they are made from.

3) Engine - does anyone know what material the inlet valves are made of?

There is a detailed report from the Department for Transport, available here: http://www.amalcarb.co.uk/TechnicalDetail.aspx?id=10

This is gonna be a major headache for not just VFR owners but anyone running pre-1993 Hondas. And not just Hondas, actually, but almost every motorcycle manufactured before the mid-Nineties.

[Maelstrom]

The tanks on the Hondas will most certainly be steel.
From what I have been able to find on the topic and based on the condition of an FZR400 that I recently bought in Thailand where Ethanol blend fuel has been in use for quite some time here are some of my conclusions to date.

Corrrosion from water:
One of the most important factors here appears to be the amount of water that is in the fuel, and the amount of extra water that the fuel absorbs. If this water could be be routinely removed then it may lessen the harm done. The tank on my FZR400 is rusted badly; though this cannot be directly attributed to E10. Perhaps some form of coating like Por15 may help. Also I have seen mention of Nickel plating for the inside of fuel tanks. It is interesting to note that fuel pump nozzles for E85 are Nickel coated and use FKM(Viton) seals.

Galvanic corrosion:
I do not know how bad this will be. However, my own FZR400 had extremely damaged rubber parts from the use of alcohol fuel but very little corrosion in the carburettor. I think that if the float bowls are regularly drained to remove water and sediment and removed for inspection at least once a year then it would be ok.

Stale fuel:
This huge problem has been ignored by too many. NBR, which is what all of the o-rings, float bowl seals etc are made of, goes hard very quickly in stale fuel and alcohol blend fuels go stale very quickly. This is a real headache. On the one hand keep you fuel tank full to avoid rust and on the other hand use the fuel quickly to avoid it going stale. What can you do?

NBR and the Fuel System:
As AdrenalineJunky pointed out in the previous post, the Amal Carburettor Company is switching everything to Viton. Most of the specific literature that relates to rubber parts in the fuel line recommends to use Viton in place of NBR. My fuel lines were actually dissolving. All of my seals and o-rings were hard to the point of being brittle. My two cents; NBR is useless and the manufacturers should have binned it years ago. To say nothing of the "carb kit" suppliers who are my competition. Use my carb kits and buy your own Viton fuel line locally. I imagine that I can expand my line to produce the tank seals etc in Viton, but I would have to do a trial with some owners and free "tank kits" to see if the fuel tap diaphragm has a long enough service life. Even if you had to replace it once a year it might be worth it.

References:
http://www.biofuels.coop/archive/viton.pdf
http://mystarbrite.com/public/pdf/LIT010V2.1-101.pdf
http://www.nee.ca/admin/documents/Flex% ... ozzles.pdf
cheers
Blair

[AdrenalineJunky]

Cheers Maelstrom.

About the water issue: there could be a problem because the tank is vented to the atmosphere, but I think this can be circumvented by fitting something holding a desiccant somewhere along the vent line. The desiccant can jst absorb the water that would otherwise find its way to the fuel and ethanol. Maybe desiccant containers could also be fitted inside the tank. http://en.wikipedia.org/wiki/Desiccant

There are already some products on sale to re-emulsify the phase-separated water/ethanol/gasoline at the bottom of a fuel tank that builds up during storage like maelstrom said could happen. Here's one http://www.defender.com/product.jsp?pat ... &id=725700. It says it is specially-formulated for dealing with E10 fuels.

There are some products available to stabilise ethanol-blend fuels during storage, for example this one.

I also found this document with probably more information than anyone would ever need http://www.goldeagle.com/UserFiles/file ... asline.pdf.

I am going to get a set of Viton lines made up. I will post here about how much this cost once I have done it. As for the fuel tap components, I would be willing to test them out, but I don't do many miles (I live close enough to cycle to my work and so the bike is just for fun). But I work in a laboratory so I could also immerse the parts in pure ethanol and leave them for some period of time, then see if they had degraded or not.

[Maelstrom]

AJ
If I make the fuel tap parts in Viton they will not need testing for ethanol compatibility. My only concern is the life of the diaphragm. Obviously it does not move much, but Viton does not have the performance in dynamic, or moving, applications that NBR does. I would just like to know how the part holds up in service. I doubt that there would be a problem. at the moment I have carb kits in Viton for 9 different bikes in the pipeline so it will be some time before I can get around to having a look at this issue. If the parts are shared, which they often are, across many models then it becomes viable for me to pay for the mould costs.

[thunderace]

You are really making a drama out of this aren't you? You'll be scaring the shit out of owners of older bikes when you have no hard and fast documented evidence of these problems. All you have is one or two bikes with issues that could be attributed to pretty much anything and your on an Ethanol witch hunt

[Maelstrom]

I did provide some references. However, here is one that uses the UK Department of Transport
http://www.sam-manicom.com/2012/03/a-qu ... f-ethanol/
I welcome a vibrant discussion and hope that it results in answers that we can all use.
cheers
Blair

[speedy231278]

Quite frankly, I think that if ethanol fuel is going to become more widespread, users of vehicles that would need bits changed to be compatible should be compensated for the expense!

[Maelstrom]

Here is the best research that I have been able to find.
http://info.ornl.gov/sites/publications ... b27766.pdf

Viton is a fluorocarbon and all of the standard seals in motorcycle carburettors are NBR. With the possible exception of the float needle which usually has a Viton tip (funny that). If you do not want to read it all this is from the summary.

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5.2.1 Fluorocarbons
Fluorocarbons yielded the lowest decrease in physical properties of the elastomers tested in this study. The addition of ethanol did not drastically affect the measured properties, and the eight fluoroelastomers exhibited only modest swell and softening (wet hardness decrease) upon exposure to the test fuels. The specimens swelled to around 20%, which is considered the upper limit for many sealing applications. Likewise the fluoroelastomers did not experience shrinkage and mass loss at the dried condition, nor did they become embrittled. Interestingly, the specimens exposed to the CE17a test fluid resulted in additional decreases in the glass transition temperature.

5.2.5 NBR
The eight NBR samples (and polyurethane) showed a pronounced increase in volume swell and softening when exposed to fuels containing ethanol. Exposures to Fuel C resulted in volume expansion approaching 20%. When exposed to the ethanol-blended test fluids, the NBRs swelled by more than 30%. Likewise, the hardness values dropped an additional 10 points when ethanol was added to the test fluid. When all of the samples (including Fuel C exposures) were dried, 8% to 14% of the mass was lost and the accompanying shrinkage was between 10% and 18%. The dried hardness was increased 5 to 16 points, indicating that embrittlement had occurred. NBR was one of only two elastomer types (the other being neoprene) that exhibited significant embrittlement in the dried state, indicating that plasticizer components were being removed by the test fuels. The results showed a high degree of variance, which is not surprising since NBR (like SBR) can be designed for a wide variety of applications. NBRs showed a significant increase in Tg with Fuel C exposure, but the addition of ethanol was observed to reduce this shift rather than extend it. Interestingly, the low volume expansion and reduced softening for the samples exposed to Fuel C suggest that these materials may in fact be acceptable for use in some E0 gasoline applications.

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And last but not least an image of said embrittlement. On the left a new original part and on the right the same part that is so hard it can snap.