This is now appropriate, and you must ignore the name of it, simply because the gear has been around since the '20's.
Remember my issues with starting my bike, which went on for around 10 months, and it was a proper nightmare for me?
I used this additive and it resolved the issue within a day, but not only that, the bike has run so sweetly ever since i can't recommend it enough.
What's held me back from mentioning it is the damn name of it......Marvel's Mystery Oil.
When you've stopped laughing, Google it and read reviews.
Bear in mind how long it's been around, it can't be bad, and what it does is clean, but more importantly, lubricate the fuel system.
The bike now starts on the button with no need for throttle, and pulls like a train.
I worked out you need about 60ml per tank, which i natrowed down to using "roughly" half a lid of a 500ml spray can.
I now use it once every 4 full tanks of fuel and it has helped like you wouldn't believe.
As said, do your research anyway, and listen to what people say, but i can honestly say it works wonders, so can only imagine it will protect against varnishing.
Using half a cap will give you about 16 goes for the near litre you get for around £14 on Ebay.
Highly recommended from me!