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TR2/3/3A TR3 Gas Tank Question


Jedi Trainee
I am missing the banjo bolt that goes on the air vent tube. I checked the big Three and can not find one. I have only seen one on Ebay, but missed bidding on it. Does anyone know where I might find one?
Thanks again


Jedi Knight
If you strike out, you can make one easily enough.
I don't really remember the size (7/16 UNF, I think?) it's easy enough to check x about 1-1/4" long...
Drill through it at the height of the center of the banjo fitting and then drill down from the end til you hit the cross drill. It will function just like the real thing! 1/8" holes will pass more than enough air to vent your tank.

Don Elliott

Obi Wan
Check with the guys who repair or sell parts for SU carbs. That top brass fitting seems to me to be similar to the banjo fittings used on all SU carbs on sidescreen TRs up to about TS 43000. I bought some of these banjo fittings easily from the local shop where they sell parts for all kinds of British Cars here in Montreal two years ago.

The banjo fitting for the front carb has two fittings - one for the inlet for Carb #1 and the other which then feeds towards Carb #2.

The banjo fitting for the inlet to Carb #2 only has the single fitting. That's the one you need.


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Great Pumpkin - R.I.P
There is also something to be said for just blocking off the banjo, and drilling a small vent hole through the inner cap. Otherwise, it can dump raw fuel out the vent even with just a moderately full tank and a moderate left turn.

Not absolutely certain, but I kind of think the tank banjo bolt is different than the early carb banjo. They at least have different part numbers, and ISTR the threads are different.


Jedi Trainee
Country flag
I second the dumping fuel piece-- everytime I fill it up, I have to be careful on LH turns lest I spill that precious premium petrol!

Small vent hole thru the inner cap you say?


Jedi Knight
Country flag
I also had to make my own banjo bolt . It was very simple to do just a pain to install.


Great Pumpkin - R.I.P
Jim_Stevens said:
Small vent hole thru the inner cap you say?
Yup. Both my original cap and the used replacement I got some years ago already had a roughly 1/16" hole but apparently not all do. With the chrome lid open, you can see the inner cap (which isn't chromed but does the actual sealing); the hole is near the center post (where the inner cap is spring-loaded to the outer chrome cap). Since my original vent tube was already in place when I discovered the problem, I just plugged it and went on for some 20 years with no problem.

Probably best to remove from the car for drilling; but if you are careful and cover the tank opening (maybe a sheet of cardboard), it could probably be done on the car.
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