Fuel tap vacuum bypass general consensus...

[tanto]

I really need to ask a stupid question. Stupid, 'cos I haven't got close to stripping down the fuel tap yet, or figuring out how it works.

Would I be right to think you could dispose of the fuel vacuum hose if you installed the fuel solenoid valve that Ricky found, above? If that's the case, and here's the stupid bit, why not do away with the fuel tap entirely?

The part I'm ignorant of, is the workings of the fuel tap/reserve fuel.

I'm thinking of building a new tank from aluminum (relatively inexpensive to do in Thailand), and I don't need a "reserve" fuel setup as I measure the fuel use closely. In this case, the fuel solenoid valve might be a perfect, esp. as it has a "Manual override lever on the valve". Does that sound sensible, or have I forgotten something?

The idea is to do away with a less reliable system, the fuel tap arrangement, and replace it with a more reliable one. Which I think goes back to the heart of the OP's question, assuming the flow rate, etc, all remain the same as the HRC setup.

[Cammo]

Would I be right to think you could dispose of the fuel vacuum hose if you installed the fuel solenoid valve that Ricky found, above? If that's the case, and here's the stupid bit, why not do away with the fuel tap entirely?

The only tricky bit I can see is that the standard fuel tap can switch between main tank and reserve level, the solenoid will not be able to switch between these without some thought behind it.

If you don't need reserve (track/race bike) you could use the solenoid quite simply.

[tanto]

Perhaps I ought to know this but, is the reserve fuel partitioned within the standard NC30 tank?

If it is, would a fabricated replica NC30 tank without a reserve partition hold slightly more fuel?

[J.B.]

Perhaps I ought to know this but, is the reserve fuel partitioned within the standard NC30 tank?

No.

Very interested in aluminium tanks if you get around to it, I'll be up in Chiang Mai next weekend. I'll give you a call.

JB

[tanto]

Very interested in aluminium tanks if you get around to it, I'll be up in Chiang Mai next weekend. I'll give you a call.
JB

Last weekend, another forum member, michaels, & I had a look for a fab. to make up NC30 tanks. Several hot hours in the sun took us to:



Daeng Glon Pratu
250 Mahidon Road
Pa Daet
Tel: 053202269 & 053202270. Mobile 0896356908



and another place, which I don't think we'd recommend. Daeng Glon Pratu took a look at Michaels' tank and quoted 12,500 baht for the same in aluminum. I think there's quite some room for negotiation. If you're serious, Michaels needs a new tank too, so that might help with the price...

The other place we visited quoted 7,500 baht but we were skeptical about the QC. As you'll know from living here, YMMV, etc., etc..

Do give me a call if you're coming to CM.

Meanwhile, back to the thread...

[tanto]

Perhaps I ought to know this but, is the reserve fuel partitioned within the standard NC30 tank?

If it is, would a fabricated replica NC30 tank without a reserve partition hold slightly more fuel?

Answer to my own question, diagram... , and explanation.

Connecting the fuel solenoid to the reserve fuel line, while capping off the standard fuel line, would seem to make sense assuming one doesn't want the "reserve fuel" function/tap. That said, I'd be wary of using fuel from the bottom of a tank that hasn't been thoroughly cleaned recently.

[porndoguk]

theres isnt a reserve section within the tank there are two pipes

the main tank pipe half way down is solid/blanked off so when the fuel level drops to reserve level it will then continue to flow,

the idea of the reserve is so that the ride knows when hes close to empty,

you could do away with the tap set it to reserve then remove the handle with a phillips screwdriver,
and relli on your millage as a fuel indicator but with this means you need to work out an average as if you nail the bike everywhere you going to use MORE fuel,

i personally wouldnt remove the tap. but im keen to try the valve in an attempt of not worrying about the vaccum hose or flooding the engine etc.

[arsey30]

This all sounds very involved.
Why not buy a length of Rick Os thick wall, long lasting with no sharp bend vacuum hose.
I no longer use the HRC mod in my taps for these reasons :-

If the tap seeps in the off position, and the bike is left for some time [over winter?] fuel may run past the piston into the sump and dilute the oil giving lubrication problems.
If the tap leaks badly [and a float needle/seating is leaking] the cylinder may fill up and overflow from the carb, or worse, partly fill it and if the engine does start at first attemp, a rod will bend, or worse.

I don't think the flow rate is much different either way, but racers remove all they can that may fail in a race, road use is different.
Dave.

[Neosophist]

The vaccumn operated tap has many benefits.

Leaving a normal / HRC tap 'on' all the while isn't necessairly a bad thing, especially on a non-faulty system. However, several situations can occur that you will have some protection from with the vaccum tap.

If the float pin stops sealing the carbs will over-flow.. this petrol will go out the overflow and possibly into the engine and oil too..

If your tap doesn't shut off on its own then it'll keep dripping till you find it or run out of fuel! I've seen this before, especially on older bikes but it's not common place, but if you leave your bike in a shed for a week and forget to turn the petrol off and come in smoking.. uh-oh.

Same applies if the bike gets knocked over, the carbs have the possiblilty to fill forever and leak all the fuel away..

Or a split / micro-hole in the fuel line which will over-time drain the tank.

The only reason it is removed is that at extended periods of WOT you can get fuel starvation to the carbs.. I have had it on the NC24 when blasting down a motorway for a minute or two.

Not had it on normal road conditions.

Still I left it there as im forgetful and it gives peace of mind.

Negatvies besides the fuel stravation at WOT are that if your vaccumn hose is old and splits it will stop the fuel flowing so your bike wont work.. broke down once becuase of this, fortuantly had spare hose with me

[Trinirides]

Ok did the HRC mod today (only bit of HRC on the bike ) and straight away the throttle response was better with nice crisp rev up..

I cheacked that the tap diaphram was sealed when doing the mod and that the tap doesnt leak when in the off position so hoping everything works out.. I wasnt able to get out on the bike as it is raining real bad and im made of suger so will hope out within the next few days ...