Fiberglass tank and racing fuel; update?

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MarcD

MarcD

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Hello all

New member/old geezer. Longtime Bultaco Metralll aficionado now graduated to Norton with a recently acquired 1973 750 Commando from long dry storage. The machine was apparently a Hi-Rider (drum front brake, small headlight, 235xxx S/N) that was outfitted with Dunstall tank, seat, fender and rear sets, then parked in an auto shop during the Reagan Administration.

As I formulate my restoration battle plan, an immediate issue is the beautiful-but-fiberglass fuel tank. The tank was completely empty with no apparent residue in the tank, and it’s never seen modern pump gasoline.

Searching this forum’s threads instantly convinced me to abandon thoughts of using any kind of tank liner, and I’ll most likely be buying an India-made steel replica for practicality and safety.

Still, I’d like to be able to occasionally use the Dunstall tank. I saw a thread from 2017 discussing VP racing fuel and wondered if this might be feasible (if costly) to use.

I spoke with Tom at VP in Texas and he suggested their MS98L blend. It’s a leaded, 98 (R+M)2 octane fuel with 0% oxygen content. It’s available locally (Northern California) at $113 per 5 gallon pail.

May I ask for personal experience and/or comment?

Great forum!
Thanks, Marc
 
Depending on how long you wait, I've been side-eyeing my Fastback tank, original fiberglass and apparently parked in the early '70s. Upon the recommendation of an anonymous tipster, I'm going to seal the inside with garage floor epoxy- the fuel-resistance I can attest to, at least in the short term, from my own garage floor. Since the tank's not yet refinished, I could get to the sealing part and let it stand with e85 in it to see how long it takes to Alienblood it's way through the hull. Or not, hopefully.
 
Hadn’t heard of that approach!

I’m just a little squeamish about tank lining in general…the product itself could be impervious to whatever that stuff is that comes out of a gas pump, but getting it to reliably and completely adhere to a non-virgin tank interior and stay intact despite heat, vibration and flexing is worrisome.

One little crack or separation and the Alienblood enters….
 
MarcD said:
Hadn’t heard of that approach!

I’m just a little squeamish about tank lining in general…the product itself could be impervious to whatever that stuff is that comes out of a gas pump, but getting it to reliably and completely adhere to a non-virgin tank interior and stay intact despite heat, vibration and flexing is worrisome.

One little crack or separation and the Alienblood enters….
Click to expand...
Truth is, I'd already planned to have a metal repop painted at the same time, which would probably make the 'glass tank a wall decoration; that being the case, it really won't matter if there's a defect from cracking. I figure this is the only way to know whether it works, or if it's another ghost. Ultimately it looks like another year at minimum before I get anything that vibrates under the tank.
 
FWIW, in 2008 I bought a new FG fastback tank from Burton Bike Bits. Since then I have used normal pump gas with whatever amount of ethanol it had on any given day with no issue at all. I sealed the tank with Caswells before its first use.

Of course, this was a new tank, made with ethanol resistant resin. Whether it was the resin or the Caswells (or both) that made the tank unaffected by ethanol for the past 14 years, I don't know.
 
I used 110 racing gas cut with 25% high test for many yrs in my FG roadster tank , no resulting damage ….
 
I have a fiberglass tank on my 1971 Roadster. It had not seen ethanol fuel as is sat for 3 decades before I refurbished it then ran it for about a month on current pump gas (I wasn't yet aware of the ethanol vs fiberglass resin problem). I quit that when I saw that the carbs & intake ports were fouled. After a lot of research, I put in 2 coats of Caswell, with glass fiber added. It has been 4 years and everything good, although it does not have a steady diet of pump gas. When I can, I run Sunoco 95 octane Optima fuel which is ethanol free. Last time I bought that fuel it cost me around $16 per gallon.
Fiberglass tank and racing fuel; update?

2 years ago I rebuilt a 1972 Interstate that also had fiberglass tank that had sat out the advent of ethanol fuel. This time, because of the size and scarcity of Interstate tanks, I took it to GTL Advantage in North Hollywood CA, who specialize in this work and had it coated there. If my memory serves me, it cost about $350. Also so far so good, but same fuel use scenario.
 
Here in east USA I use non-ethanol or Aircraft fuel, Knock -on-wood no sign of problems! Some where there was a post that said Sonoco 99 was ethanol free?!?!?
 
The hassle of screwing around looking for non-ethanol gas for a street bike is way beyond my tolerance limit. When I'm out on on a ride and it's time to re-fill, the last thing I would want to deal with is worrying about finding a station that has ethanol-free gas.

Re that - I have seen absolutely no issue with ethanol gas that is worth worrying about. If it's going to sit in the tank unused for an extended period, a shot of StaBil will eliminate any problems for at least a year from my personal experience (StaBil claims two years).

That being said, I agree that buying a metal tank is preferred to an FG tank IF the appropriate style is available in metal. When I converted my Roadster to a Fastback in '08, the only fastback tanks I could find new were FG. Maybe now there are metal ones available but, as I said earlier, my FG tank has been on the bike for 14 years and so far I don't see any sign that a replacement will ever be necessary.
 
Carry a tube of lead additive. In Aus it’s available at all petrol stations.
 
VP C12 leaded has no ethanol. its 112 octane. its around $125 right now and is common among suppliers because so many vehicles use it.

or at least it was.

i use it in a race bike and then mix what i have left into non-ethanol pump gas for my fibreglas commando
 
thanks to all for the input/thoughts!


Given the lengthy restoration road ahead for this long slumbering machine, and my likely planned intermittent use, I picked up a 5gal pail of VP MS98L to use while I sort this bike out. Will use the Dunstall glass tank for now.

Long term, I’m pondering the various eBay India sellers for a metal tank. There’s a generic pic used by many sellers of a reasonably close unpainted Dunstall style tank (a bit too rounded, gas cap not offset) that sells for between $235 to $425, with a variety of shipping options. Some sellers have pretty colorful feedback and most use boilerplate/stilted language that’s not reassuring, and there’s one that professes to be in Dublin, CA (I’m in San Francisco), but they don’t allow in person pickup. Hmmmmm…

Again, thanks to all; great to finally own a Norton, and very appreciative of this great forum!

Cheers,
Marc
 
A few points here. I've seen glassfibre tanks that were melted by the ethanol in fuel. The substance that's "melted" off the inside of the tank sits in the carb float bowls like a thick layer of clear paint. Of course, it coats the float, the needle, the needle seat, the carb bore and throttle slide, too. At first, it's sticky; later, it hardens up. This is not good. Of course, usually the tank begins to leak from the glued up flanges around the edges where the tank bottom is bonded to the outer shell. Some people get away with ethanol in old tanks, I won't take the chance.

Lead will do nothing to make your fuel more stable between rides and will do nothing to protect your glass tank.
There are three stations that sell non-ethanol fuel within three miles of my house, come to think of it, I don't that that there's a station that doesn't closer than the first one that does. As humid as North Carolina is, ethanol will fill a tank (metal or glass) with water that it draws out of the air. People around here call non-ethanol gasoline "lawn mower gas" or "boat gas" and people buy a lot of it. Add it to the fact that the ethanol seems to speed up the "furry corrosion" that blocks the idle circuits and other carb parts in an old-style Amal carb (the ones cast with zinc pot-metal, the Premiers are better but I've seen some pretty ratty Premiers and also some ratty Japanese carbs that have been run with ethanol fuel).

The idea of $20 /gallon fuel gives me the chills. Of course, nowadays the price of all gasoline is swinging around like a spare dick at a redneck wedding but generally, non-ethanol pump gas can be purchased for about $4 /gallon. I happen to have access to a supply of Av-gas; a small amount must be regularly drained from sales pump systems and aircraft fuel systems to check for water and debris and the drained samples cannot be poured into an aircraft's tanks, so there's usually a bit around that's discarded as HazMat, burned in lawn mowers, etc.. Almost all "Av-gas" is the 100Low Lead grade but what they don't tell you is Av-gas used on some WWII bombers was 145 octane so "Low Lead" is only by comparison, it still has at least three times the lead that was in 100 octane leaded Sunoco racing gas in 1976. It's also formulated with a high vapor pressure to avoid vapor lock at altitude and it's NEVER brewed with ethanol.
Anti-knock lead in gasoline is odd stuff. A little of it will give you a good octane improvement but to get a little more octane improvement, you've got to go way up on the amount of lead additive. So, the fact that you can use Av-gas as an additive is a perfect situation. So, I buy 4 gallons of non-ethanol gas at the pump (99 octane RM) for $4 and add half a gallon of Av-gas. It's an incredibly high-performing fuel, in fact, if you're running a low-compression engine, you probably shouldn't use it because the high octane will interfere with fuel ignition in your combustion chambers. But if you want to do some quick riding and you're running a healthy compression ratio, it's a very good fuel. If I had to pay for the Av-gas, it would probably be about $3.50 for a half gallon and that that's still less than $20 for five gallons.

But, come on, glassfibre tanks are old tech. Using them in 2022 is a needless risk -- even if you're about to find a new one, the thought of using a 50-year old tank is reckless.
(Futher discussions about switching off petcocks and running your carbs dry before you shut down and/or draining a tank for storage gratefully recieved.)
BH, North Carolina, USA
 
Blewdy Yaink said:
A few points here. I've seen glassfibre tanks that were melted by the ethanol in fuel. The substance that's "melted" off the inside of the tank sits in the carb float bowls like a thick layer of clear paint. Of course, it coats the float, the needle, the needle seat, the carb bore and throttle slide, too. At first, it's sticky; later, it hardens up. This is not good. Of course, usually the tank begins to leak from the glued up flanges around the edges where the tank bottom is bonded to the outer shell. Some people get away with ethanol in old tanks, I won't take the chance.

Lead will do nothing to make your fuel more stable between rides and will do nothing to protect your glass tank.
There are three stations that sell non-ethanol fuel within three miles of my house, come to think of it, I don't that that there's a station that doesn't closer than the first one that does. As humid as North Carolina is, ethanol will fill a tank (metal or glass) with water that it draws out of the air. People around here call non-ethanol gasoline "lawn mower gas" or "boat gas" and people buy a lot of it. Add it to the fact that the ethanol seems to speed up the "furry corrosion" that blocks the idle circuits and other carb parts in an old-style Amal carb (the ones cast with zinc pot-metal, the Premiers are better but I've seen some pretty ratty Premiers and also some ratty Japanese carbs that have been run with ethanol fuel).

The idea of $20 /gallon fuel gives me the chills. Of course, nowadays the price of all gasoline is swinging around like a spare dick at a redneck wedding but generally, non-ethanol pump gas can be purchased for about $4 /gallon. I happen to have access to a supply of Av-gas; a small amount must be regularly drained from sales pump systems and aircraft fuel systems to check for water and debris and the drained samples cannot be poured into an aircraft's tanks, so there's usually a bit around that's discarded as HazMat, burned in lawn mowers, etc.. Almost all "Av-gas" is the 100Low Lead grade but what they don't tell you is Av-gas used on some WWII bombers was 145 octane so "Low Lead" is only by comparison, it still has at least three times the lead that was in 100 octane leaded Sunoco racing gas in 1976. It's also formulated with a high vapor pressure to avoid vapor lock at altitude and it's NEVER brewed with ethanol.
Anti-knock lead in gasoline is odd stuff. A little of it will give you a good octane improvement but to get a little more octane improvement, you've got to go way up on the amount of lead additive. So, the fact that you can use Av-gas as an additive is a perfect situation. So, I buy 4 gallons of non-ethanol gas at the pump (99 octane RM) for $4 and add half a gallon of Av-gas. It's an incredibly high-performing fuel, in fact, if you're running a low-compression engine, you probably shouldn't use it because the high octane will interfere with fuel ignition in your combustion chambers. But if you want to do some quick riding and you're running a healthy compression ratio, it's a very good fuel. If I had to pay for the Av-gas, it would probably be about $3.50 for a half gallon and that that's still less than $20 for five gallons.

But, come on, glassfibre tanks are old tech. Using them in 2022 is a needless risk -- even if you're about to find a new one, the thought of using a 50-year old tank is reckless.
(Futher discussions about switching off petcocks and running your carbs dry before you shut down and/or draining a tank for storage gratefully recieved.)
BH, North Carolina, USA
Click to expand...
Thanks for a very informative reply!

Since last posting, I did pick up a 5 gallon pail of VP 98L ethanol-free/leaded racing fuel to use while sorting the bike out. If my nose is correct, this fuel contains a fair amount of toluene, which I believe was a common av-gas octane booster.

I’m in Northern California, where premium pump gas averages $6/gal, is 91 octane and almost universally 10% ethanol.

Fuel issues aside, a metal tank is the direction I’m taking….just seems safer regarding garage fires or rupture in a collision.
 
MarcD said:
I’m in Northern California, where premium pump gas averages $6/gal, is 91 octane and almost universally 10% ethanol.

Fuel issues aside, a metal tank is the direction I’m taking….just seems safer regarding garage fires or rupture in a collision.
Click to expand...
I'm down in Santa Cruz, and I haven't been able to find non-ethanol gas at a pump in years. Pretty sure it's illegal in CA out of a pump. Maybe some loophole somewhere allows it, but not anywhere I have found while filling up.

For the Indian Ebay tanks, maybe get an unpainted one, so if you need to persuade it to fit, you're not paying for the paint to be redone. Some of them apparently come kinda rusty inside so a fresh dip might not be a bad deal either.

I've heard the seller royalchoppers has a decent reputation, but can't vouch personally.

Welcome to the forum. Sounds like your bike could be pretty fun.
 
Welcome, and what a fascinating transformation - from Hi Rider to racer then? You are fortunate to be local to the NorCal branch of Norton owners there is plenty of expertise you can draw on and of course those group rides are phenomenal. I agree with the need to pre-fit any tank, original or otherwise, prior to painting. I have two original Roadster tanks and one from India and I will say the tank from India is pretty solid. Royalchoppers is the best of the bunch from what I have heard.

There is a gentleman in Oregon who will dip and strip a tank for $100 - I can pm this to you if you purchase a used OEM tank or have need otherwise. Good luck and have a look at Alan's post here about the rebirth of love for the Norton Commando. My first (308305) is long gone, a JPN covered in Oklahoma red dirt, now in Norway, the third currently on the lift being restored, and the fourth (and last?) in the garage for a strict warmover as it is very original.
 
Blewdy Yank writes: "But, come on, glassfibre tanks are old tech. Using them in 2022 is a needless risk -- even if you're about to find a new one, the thought of using a 50-year old tank is reckless."

Needless risk. Reckless? Language seems a bit strong.
If you have a fiberglass tank, and it works, good enough.
What risk are you running? It might leak. It might mung up your carb. It might wreck a nice paint job. Then line it. And if that fails? Hang it on your wall. Big deal.
 
This risk, misplaced in 1973, seems particularly irrelevant in 2022.
More to the point, I was asking Blewdy Yank to elaborate on his concerns.
 
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