• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

TR2/3/3A TR3 gas tank vent

TFB

Jedi Knight
Country flag
Offline
Can anyone tell me the tubing size for the late tr3b tank vent.I dont have bango setup for the 1/2 nf threads.I may drill and tap for a 3/8npt and run 1/4 copperX 3/8 npt compression 90,or ?
Also does vent tube attach to anything, how much does it protrude past floor grommet,and does it go anywhere under the car or just stick through the grommet a little?
Thanks
Tom?
 

PeterK

Yoda
Offline
It might be 1/4 or 5/16, just goes through the trunk floor and hangs there. It's just a vent but when your tank is full it can also be an overflow so keep that in mind.
 

Geo Hahn

Yoda
Country flag
Offline
Mine is held by a clip (like the ones that secure the fuel line to the frame). Looks to be 5/16":

TR3%20Tank%20Vent.JPG
 

Twosheds

Darth Vader
Offline
PeterK said:
It might be 1/4 or 5/16, just goes through the trunk floor and hangs there. It's just a vent but when your tank is full it can also be an overflow so keep that in mind.

On hard lefthanders.
 

TR3driver

Great Pumpkin - R.I.P
Offline
Twosheds said:
On hard lefthanders.
Not even all that hard, if the tank is nearly full. With 3/4 tank, I was spilling fuel just turning left from a stop sign onto a major road (45 mph, part of my daily commute to work).

My suggestion is to block the original vent entirely, and add a small hole (if there isn't one there already) to the inner plate of the gas cap. I've been running that way for many years and it works for me.

In a full service gas station (so you know it was a long time ago
grin.gif
) once, the attendant kept topping up the tank even after it was above the overflow. I had to yell at him to stop, as he hadn't noticed the spreading pool of gasoline under his feet.
 

Geo Hahn

Yoda
Country flag
Offline
Yep, I try to remember to not fill the tank too full but seems like someone always comes over with the 'I used to have one of those...' and I get distracted until the pump clicks off.

Then my cologne du jour is Eau de Shell.
 

Twosheds

Darth Vader
Offline
Years ago my friend was following me on his '68 Triumph Bonneville. I went around a hard lefthander. When I looked in the mirror, I noticed that he had fallen far behind! He didn't drop the bike, but had a few anxious moments. He cautiously caught up, then noticed that the road only became slippery in hard lefthanders (the tank was't completly full, Randall) and stayed close unless we came to one.
 
OP
T

TFB

Jedi Knight
Country flag
Offline
Thanks for all the good info,and Geo for the pictures of clip under car.
Randall,I checked my cap,and I guess you mean drill hole in spring plate I like that idea,no hole there now(not much of the gasket left either).Seems like a little diaphram vent/check should be avaliable for similar applications.
I never thought about the overflow problem with the vent being lower than fill neck,or turn spillage.Funny I had a 61 TR3 40+ years ago and dont remember problems with spillage.Mabe never had enough money to fill the tank at 35cents a gallon.
Thanks again for all the replies,
Tom
 

TR3driver

Great Pumpkin - R.I.P
Offline
Twosheds said:
He didn't drop the bike, but had a few anxious moments.
Man, I hate it when that happens! I presume you were going fast enough that he just got a lungful of fumes and maybe a few drops on his faceplate; rather than enough being on the road to make it slick.

Part of the reason I quit riding, you just never can tell when a slick spot will appear under your front wheel.
 

TR3driver

Great Pumpkin - R.I.P
Offline
TFB said:
Randall,I checked my cap,and I guess you mean drill hole in spring plate
Here's a photo of mine. Pretty sure I didn't drill it myself, but it's possible I did and just forgot about it.

Gastankventholeincap.jpg
 
OP
T

TFB

Jedi Knight
Country flag
Offline
Thanks for the pic Randall.
I thought thats where you meant.
I am thinking of doing the same or going with aftermarket vent/rollover valve.

Thanks
Tom
 

Twosheds

Darth Vader
Offline
TR3driver said:
Man, I hate it when that happens! I presume you were going fast enough that he just got a lungful of fumes and maybe a few drops on his faceplate; rather than enough being on the road to make it slick.

Part of the reason I quit riding, you just never can tell when a slick spot will appear under your front wheel.

He slipped, but was able to recover before going down.

Good thing, too; it is a beautiful bike, restored by my friend.

Just before we left my house: Man, that was a long time ago! Look no graybeard!
 

Attachments

  • 23839.jpg
    23839.jpg
    48.9 KB · Views: 92
Similar threads
Thread starter Title Forum Replies Date
J TR2/3/3A TR3 gas tank mystery Triumph 5
S TR2/3/3A how to install a gas tank in an early tr3 Triumph 8
tinman58 TR2/3/3A TR3 gas tank? Triumph 2
T TR2/3/3A TR3 aluminum gas tank on eBay Triumph 4
T TR2/3/3A remove a tr3 gas tank Triumph 7
K TR2/3/3A TR3 gas tank inlet size? Triumph 2
R TR2/3/3A TR3 gas tank Triumph 13
af3683 TR2/3/3A TR3 Trunk Plugs Near Gas Tank Triumph 3
af3683 TR2/3/3A Installing TR3 Millboard Gas Tank Cover Panel Triumph 5
K TR2/3/3A 57 TR3 gas tank hold down strap mistery? Triumph 5
S TR2/3/3A One more tr3 gas tank? Triumph 1
S TR2/3/3A tr3 gas tank vent Triumph 3
S TR2/3/3A gas tank in a 1961 tr3 Triumph 12
S TR2/3/3A Tr3 gas tank again Triumph 3
tinman58 TR2/3/3A Another TR3 gas tank ? Triumph 3
mountainman TR2/3/3A TR3 Gas Tank Question Triumph 7
H TR2/3/3A TR3- installing gas tank = nightmare Triumph 18
martx-5 TR2/3/3A TR3 Gas Tank Installation Triumph 5
S TR2/3/3A Tr3 gas tank repair Triumph 9
martx-5 TR2/3/3A TR3 Gas Tank Triumph 3
T For Sale TR2 - TR3 Gas Cap for sale Triumph Classifieds 1
S TR2/3/3A TR3 gas filler cap Triumph 1
K For Sale TR3 Gas Cap Assembly Triumph Classifieds 0
M TR2/3/3A TR3 gas cap question Triumph 4
J TR2/3/3A Help!! Gas smell from Tr3! Triumph 21
S TR2/3/3A Tr3 Gas pedal height from floor Triumph 15
S TR2/3/3A tr3 gas gauge calibration resisters Triumph 12
S TR2/3/3A tr3 gas gauge Triumph 5
T TR2/3/3A TR3 gas tanks Triumph 9
mountainman TR2/3/3A Tr3 Gas Additives Triumph 23
S TR2/3/3A late tr3 gas cap? Triumph 5
S TR4/4A late tr3 and tr4 gas caps Triumph 4
S TR2/3/3A Tr3 gas cap vent Triumph 0
K TR2/3/3A TR3...Gas cap rubber gasket/seal in cap lid? Triumph 1
S TR2/3/3A Tr3 gas tanks Triumph 7
Tinkerman TR2/3/3A TR3 Gas Stop Tap Needed ! Triumph 6
K TR2/3/3A TR3 Gas Line Shut-off Valve Triumph 12
S TR2/3/3A gas gauge TR3 Triumph 7
J TR2/3/3A gas leak on a TR3 Triumph 4
RedTR3 TR2/3/3A TR3 - Gas odor and poor mileage Triumph 5
S TR2/3/3A Tr3 gas pedal Triumph 3
J TR2/3/3A tr3 and unleaded gas Triumph 9
S TR2/3/3A TR3 Gas Mileage Triumph 9
Bill TR2/3/3A TR3 gas gage Triumph 2
S TR2/3/3A Tr3 gas pedal shaft socket Triumph 7
1 TR3 Fender spats sold on EBay. Triumph 0
J TR2/3/3A What size speedi-sleeve needed for pinion seal on a TR3? Triumph 6
T For Sale Free - Body Jig for TR3/TR3A Triumph Classifieds 0
J TR2/3/3A TR3 engine cylinder top clearance Triumph 22
BillyB62 TR2/3/3A Looking for the Owner of a TR3 Triumph 5

Similar threads

Top