Triumphrat

Carbonbased · 12-20-2009, 07:53 PM

I've been perusing a reprint Triumph owner's handbook for my 68 Trophy baby, which regarding the fuel taps says, "Turn down the lever on the right tap for normal running. When the reserve is required turn down the lever on the left tap. Always turn off both taps when parking."

But it seems everyone I've encountered so far who is accustomed to the Meriden bikes turns on both taps as a matter of routine, even when the tank is full.

I turned on the right tap only and went for a couple of rides and had no problems.
Is there any particular reason why the custom seems to be to run both taps open all the time?

Webby · 12-20-2009, 08:00 PM

Hi Carbon,
The idea is that with only the R/H tap open the fuel to the left carb takes a bit longer to get there (via the banjo on the bottom of the float bowl) This works OK when you're out for a gentle ride. However if your are riding hard or racing, especialy if there are lots of curves it is recommended that both taps are open to get the fuel to the L/H carb a bit quicker.
I don't know if there is any difference in reality, but that at least is the theory

Webby

Carbonbased · 12-20-2009, 09:47 PM

Yes, that makes sense, Webby - thanks.

My bike being a TR6 with only one carb in the middle wouldn't have that particular issue in practice, but now I can see how people who have ridden the two carb models much would just get into a habit of turning both taps on for that reason.

RetroRod · 12-21-2009, 12:31 AM

Quote:

Originally Posted by Webby

Hi Carbon,
The idea is that with only the R/H tap open the fuel to the left carb takes a bit longer to get there (via the banjo on the bottom of the float bowl) This works OK when you're out for a gentle ride. However if your are riding hard or racing, especialy if there are lots of curves it is recommended that both taps are open to get the fuel to the L/H carb a bit quicker.
I don't know if there is any difference in reality, but that at least is the theory

Webby

Something wrong there Webby! Racing maybe, but on the road the RH tap will deliver all the fuel necessary, full stop. The LH, if it is indeed a genuine reserve (some owners replace it with a normal run tap) simply gives you a way out if you didn't check the tank level before you went riding (or the trip meter doesn't work, was not reset, etc.) RR

Skidemon44 · 12-21-2009, 01:26 AM

I must say that my 72 will only run properly with both taps open.

If I don't turn the left tap on, the left carby splutters and coughs but as soon as I open the tap, all is sweet.

My 79 on the other hand runs fine with just the right tap open.

RetroRod · 12-21-2009, 01:33 AM

Quote:

Originally Posted by Skidemon44

I must say that my 72 will only run properly with both taps open.

If I don't turn the left tap on, the left carby splutters and coughs but as soon as I open the tap, all is sweet.

My 79 on the other hand runs fine with just the right tap open.

Something wrong here. You have a feed problem that should not simply be fixed by turning the other tap on. The 2nd tap was always for reserve just like the manufaturer said. RR

trayden · 12-21-2009, 06:43 AM

I am only using my right hand one with no problems!

I have never opened both on the three bonnies that I have had.

Den

Skidemon44 · 12-21-2009, 08:01 AM

Quote:

Originally Posted by RetroRod

Something wrong here. You have a feed problem that should not simply be fixed by turning the other tap on. The 2nd tap was always for reserve just like the manufaturer said. RR

I've already figured that out, but have little time to sort it out at the moment. Remember this bike only has 110 mile on the clock since the rebuild and about 80 of that was done in one trip!

Carbonbased · 12-21-2009, 09:04 AM

Could it be then that the routine practice of opening both taps evolved because many bikes have slightly clogged taps, filters, or lines on the main side and so opening both taps is necessary to provide enough fuel flow / volume for acceleration or leaning into curves?

Being a lazy, if not inglourious, "basterd" meself, I'd probably take that easy way out for a while before, say, going to the trouble to replace a tap...

dogtired · 12-21-2009, 09:09 AM

If I only turn one on, only one carby works...
(no fuel line between carbies.)
I don't have a choice.