Triumphrat

2008superduke

So why did Triumph use two gas lines on some daytonas and one on others. The second line goes do a silly little air reed type valve, looks pointless, really why?

2008superduke

Bueller

Surfguygriff

It's for air pressure relief. One way valve


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kubbie

Going by my TT, there are 2 fuel lines and 2 vent lines.

All this is assuming bike is stock and original.

Fuel, line with red end is the high pressure line. The one with the white end is the return line.

Vent lines, one is for venting pressure out of the tank, it has a one way valve on it. The other drains around the gas cap, so water doesn't go down in the tank when you open it.

There is also a hard plastic vacuum line that goes from the computer under the pass. seat to the RH side of the fuel rail and plugs into a vacuum diaphragm/fuel pressure regulator.

Now, half way through the Daytona production run T updated the computer and fuel system, including the fuel lines. Don't know what is different internally though.

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kubbie
"I'll call you if you need me"

flashotter

Does anyone know which line goes to which fitting as they are interchangeable,or does it matter?, since you can plug either one into either hole.

Bwadejs

Im pretty sure they are not interchangeable as kubbie said one is high pressure and the other is return. I had to replace my orings yesterday as one was squirting petrol all over my chain without me realising...that explained the sudden slackness of it :/
I dont remember which pipe the feed is but i know as you sit on the bike with the tank on the red valve is on the left hand side and this is the high pressure feed pipe that puts the fuel in the engine...follow both pipes and im sure you can work it out simply by where they go...and careful reconnecting them. If you pinch the oring at all when you refit the pipes youll spring a leak like i did and it started so small i could only smell petrol when warm (just after running while petrol was still in tank and under pressure) ....good luck

DEcosse

One is supply and the other is return, but they are at virtually same pressure (3 bar) - the return is at same pressure because is part of the same 'vessel' and the pressure regulator is actually AFTER (in terms of flow) the return fitting.
Although the manual stresses to connect them correctly, in practical terms it makes no real difference to running performance - fuel simply flows the other direction to the fuel rails but still provides the same flow and pressure at the injectors. The only other difference is that the return hose is slightly larger diameter but again makes no practical difference in terms of performance/running.
Not suggesting to ignore the advice - just that in real World there are no negative consequences.

Back to original question:

On earlier models up to Serial # 201541 on the Daytona, Triumph used the two-line Supply/Return system to fuel rail, with the pressure regulator connected AFTER the return fitting.
This was the standard config on all Triumph FI models from 97 to about 2004.
Beyond that, the pump systems were reconfigured to a single supply only, where the fuel pressure is regulated BEFORE the supply fitting.
Again, this change affected virtually all the FI models at about same time-frame.

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Will

I had been wondering why that was the case. I thought it had to do with the switch to Kiehin from Sagem, but some S4s use the later style disconnect. Now I know why. Thanks.

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Will
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DEcosse

Same thing with the 955 Daytona's Will - in 2005 they switch to the single supply feed rail but still uses exact same map in the Sagems.
There is of course no possibility to reference to manifold pressure with a single line pump system

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