Bunch of beginner questions

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abmartin
SSD900 Darmah
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Re: Bunch of beginner questions

Post by abmartin » Thu May 24, 2012 4:04 am

If I were you I'd be concerned. Your old man on the Duke might whup your Norton's arse. :lol:

Bruce
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swooshdave
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Re: Bunch of beginner questions

Post by swooshdave » Thu May 24, 2012 7:18 am

abmartin wrote:If I were you I'd be concerned. Your old man on the Duke might whup your Norton's arse. :lol:

Bruce
I'll take that chance. :rad:

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Craig in France
Cagiva Elefant
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Re: Bunch of beginner questions

Post by Craig in France » Fri May 25, 2012 1:13 am

(To get back on topic ... :blah: :-D )
swooshdave wrote: Question, if there's a crossover on the fuel lines then why is there two reserves?
Good question. Not something I've thought about before. With the tank full, one tap can normally flow enuf gas to keep both float bowls full (altho' possibly not at sustained FOT? I don't know, 'cos I always run with both taps on.) So I can't see why a single tap wouldn't continue to fill the float bowls when switched to reserve. Maybe it was just easier = cheaper to make one tap body?

Btw, I've seen a fair number of taps with the reserve tube - arrowed below - missing. Which means no reserve function: when you're dry, you're dry ...

Image
swooshdave wrote:Do you guys run both taps open all the time?
Personally, yes. But I can't pretend I know why. Force of habit, I guess ...

Ciao

Craig

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swooshdave
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Re: Bunch of beginner questions

Post by swooshdave » Fri May 25, 2012 11:36 am

I assume that when there are two taps on the tank one is reserve and the other main. Typically when there is a single tap it contains both the main and reserve function.

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Craig in France
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Re: Bunch of beginner questions

Post by Craig in France » Fri May 25, 2012 12:02 pm

Yeh, that would make sense, of course; but you often find that both taps have a reserve function/facility. Guess it needs someone more canny/experienced than I to explain why .... :-D

Ciao

Craig

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swooshdave
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Re: Bunch of beginner questions

Post by swooshdave » Fri May 25, 2012 12:22 pm

Craig in France wrote:Yeh, that would make sense, of course; but you often find that both taps have a reserve function/facility. Guess it needs someone more canny/experienced than I to explain why .... :-D

Ciao

Craig
Two reasons I can think of:

It was cheaper to buy one type of tap (with both main and reserve).

Or as Ducatis are more sporty that most bikes (ie non-Nortons) that they need the extra tap to flow enough fuel for "spirited riding".

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BevHevSteve
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Re: Bunch of beginner questions

Post by BevHevSteve » Fri May 25, 2012 3:31 pm

no - each tap does have an ON / OFF / RESERVE. Remember that the earliest twins used dual taps with crossover and each tap body was in fact different, just look at them. Left side tap has right facing outlet that goes back to the rear cylinder plus the center facing outlet for the crossover. The right tap has the center facing outlet for crossover plus a down facing outlet for the forward cylinder - 12 x 1.5mm type taps fit 750GT/Sport/Super Sport, early 860GT etc, Early 900 Super Sport. Around 1980ish they switched to the single outlet type taps that are 16 x 1mm thread, each with on / off / reserve outlets pointing either to the left or right on Darmah, later 900SS, pantah etc.

The square bodied 12 x 1.5 taps, when mounted, reserve is rear, off is forward, on is down plus the different outlet locations so these bodies are different to eachother, not the same bodies.

I always ride with both taps on, it would be silly to not. Also remember that tanks such as the Darmah, hold gas on each side of the tank when low....
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swooshdave
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Re: Bunch of beginner questions

Post by swooshdave » Fri May 25, 2012 5:59 pm

Image
Right side

Image
Left side

Levers look different, was one replaced?

As for the silly part, as long as a single tap could flow enough fuel, in theory you would only need to use one tap until your fuel got low.

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BevHevSteve
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Re: Bunch of beginner questions

Post by BevHevSteve » Fri May 25, 2012 6:55 pm

yes bottom photo shows correct lever.

Nobody said 1 of these taps flowed enough for both carbs. I would doubt that to be the case, especially as they kept 2 taps on bevels and pantahs and although they changed the tap type, along the way, they never went to 1 tap. But hey it's your bike if you want to take the chance of leaning out completely and burning up your valves, go for it. First your pipes will start glowing red hot - that will be the beginning of the end....
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ducadini
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Re: Bunch of beginner questions

Post by ducadini » Fri May 25, 2012 11:51 pm

I always ride with one tap on and the other on reserve, without the fuel line between both taps.
Usually my "spirited riding" sloshes the fuel around to divide it rather evenly over the two halves.
So when one side runs out, there's just one carb that runs out and the engine doens't die, just give a few pops and bangs.
Time enough to switch the other on reserve and carry on.
Or You could cut a piece of one of the inner tubes so the level and moment of reserve are different.
cu
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