Removing fiberglass resin from carbs and intake

After dragging it around for 38 years in baskets, I finally put my '71 Roadster back together and have it running. It is at this point that I have become aware of the fiberglass tank vs ethanol issue. I figured that since it hadn't consumed any ethanol till the last couple months that I would just have the issue of dealing or replacing the tank. To my surprise, I find that there is already sticky resin residue in my carbs and intake ports. I have followed several threads on the ethanol issue and on carb cleaning but have not found anything describing products or techniques specific to removing the resin residue. What is the best way to do this?

NickZ said:

After dragging it around for 38 years in baskets, I finally put my '71 Roadster back together and have it running. It is at this point that I have become aware of the fiberglass tank vs ethanol issue. I figured that since it hadn't consumed any ethanol till the last couple months that I would just have the issue of dealing or replacing the tank. To my surprise, I find that there is already sticky resin residue in my carbs and intake ports. I have followed several threads on the ethanol issue and on carb cleaning but have not found anything describing products or techniques specific to removing the resin residue. What is the best way to do this?

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I've had good luck using denatured alcohol, under the theory that what dissolved it in the first place can do it again.

Methylene chloride
: a main ingredient in paint stripper/brush cleaner. Or on it's own...
Be careful if you have a heart condition.

I had this happen on a borrowed bike! Went to a race meeting with it and filled it with ethanol rich fuel! Only took minutes before there were problems and the throttle stuck open, yes, two carbs full of resin.

Pulled the head and there was plenty on the valves and stems.

Pump fuel shifted a lot of it, probably fuel with less ethanol, but I don't recall 100%. Specialist carb cleaner some more, but I also took the carbs for ultrasound cleaning to finish the job.

Bike ran fine when I rode it at a later date with my own alloy tank on it!

I would try a long soak in Acetone....like weeks or months. It should work it's way through polyester resin if that is what has migrated to carbs. Methyl Chloride also effective but more nasty to work with.

Thanks for the suggestions. I already have denatured alcohol so I will try that. Couldn't find a source for methyl chloride. If the dn doesn't do the trick, I'll try acetone.
Cleaning the carbs and manifolds seems straightforward, but I'm not sure about the best technique for the intake ports. There doesn't appear to be residue on the valve or valve guide. Mainly on the walls of the intake ports. Should I just fill the ports with the solvent and let it soak for a while before scrubbing? I would hat to have to pull the head again.

NickZ said:

Thanks for the suggestions. I already have denatured alcohol so I will try that. Couldn't find a source for methyl chloride. If the dn doesn't do the trick, I'll try acetone.
Cleaning the carbs and manifolds seems straightforward, but I'm not sure about the best technique for the intake ports. There doesn't appear to be residue on the valve or valve guide. Mainly on the walls of the intake ports. Should I just fill the ports with the solvent and let it soak for a while before scrubbing? I would hat to have to pull the head again.

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How about soaking a rag in the DN and stuffing it in the port to soften things up, then scrub.

My fastback tank melted like that and it left resin on the inlet valves stopping them from fully closing
I couldn't work out why performance was gradually dropping

Acetone.... will work fine as a brush cleaner, but only when the resin is still wet, not when it has gone hard, as the stuff is stuck to the metal the only course of action is to use a soft brass rotary brush and /or scraper to remove. Using chemicals, especially the nasty types have their own problems and require their own ‘ealth and safely issues. . . . .

Is there a passage way with the Amal Premiers that would cause one side popping between 1500-3000 rpms.?

Yuck... all too familiar. I had my throttles stick wide open, or nearly so too, but on the road. I took it all apart and used carb cleaner and a stiff brush and a rough rag with elbow grease. Had to do that twice because I didn't know what the heck was happening a few years ago. I used to strip the EtOH from the gas using H2O via phase separation (thanks youtube) and that works fine unless you actually want to go somewhere. Finally bought an Indian steel Interstate tank to put on my Dunstallized roadster. It fits great actually with the Dunstall seat-tail piece. Its sitting in my garage right now in Magalia California if its still in one piece. I'm currently evacuated due to the "Camp Fire", along with my '67 MGB GT and everything else I own except my 2 dogs and a change of clothes and my old trusty 1999 Isuzu Trooper. No worries, my son and I are alive and safely with friends, no sympathy needed, except maybe for old #305750.

Denatured alcohol seems to work great. The residue came right off carbs and manifolds with a little wiping. I am trying the alcohol soaked rags with the intake ports, as suggested by Cyclegeezer. That seems to be working also, but after scrubbing I plan to fill the ports with the denatured alcohol and let it soak for a day or so then siphon out.

L.E.N. said:

Yuck... all too familiar. I had my throttles stick wide open, or nearly so too, but on the road. I took it all apart and used carb cleaner and a stiff brush and a rough rag with elbow grease. Had to do that twice because I didn't know what the heck was happening a few years ago. I used to strip the EtOH from the gas using H2O via phase separation (thanks youtube) and that works fine unless you actually want to go somewhere. Finally bought an Indian steel Interstate tank to put on my Dunstallized roadster. It fits great actually with the Dunstall seat-tail piece. Its sitting in my garage right now in Magalia California if its still in one piece. I'm currently evacuated due to the "Camp Fire", along with my '67 MGB GT and everything else I own except my 2 dogs and a change of clothes and my old trusty 1999 Isuzu Trooper. No worries, my son and I are alive and safely with friends, no sympathy needed, except maybe for old #305750.

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L.E.N. I feel for you. 11 months ago it was me evacuating for the Thomas Fire. Good luck.

I wiped down the intake ports including any parts of the valves and valve guides I can reach after removing the alcohol soaked rags. That removed most of the residue from the surfaces I could reach. I could see significant residue on the spots I could not reach to scrub. At that point I filled the ports with the denatured alcohol and let it soak over night. The next day I siphoned the liquid out and wiped the ports down again. I could see improvement, but still residue remained on the back of the valves and other spots I could not wipe. I repeated this last step again. Again improvement, but I also notice what looks like a deterioration of the aluminium near the ends of the valve guides. I didn't expect that and I hope that it is not significant enough to cause a problem. I wasn't aware that denatured alcohol might react with aluminium, and I would not recommend doing this. A different solvent that does not effect the materials used in the intake ports would be a better choice.