[Rod Rocket]

Hi Guys.

Always like to learn other Riders preferences and opinions.



Should I go for clear braided, or solid black Fuel & Balance hoses for my 1977 T140V Bonneville which uses Amal Concentric Mark 1's?


Also, a side question.

My manifolds have hose attachment points for a balance hose.

The Amal Concentric Mark 1's each have two hose attachment points, presumably one on each also being for a balance hose.

Does the fuel system require balancing both at the carbs and at the manifolds?

Also, on the carbs, how do I identify which are for fuel from the tank and which are for balancing?


Thanks.

R R

 

[wol]

when you say your carbs have two attatchments for hoses - i assume you are refering to the double banjo fitting at the bottom of the carbs bolted to the float bowl ? -- these are both for fuel -- you will have a fuel hose from each tap on the fuel tank to the "outside" hose connection on each carb - then the inner connections have a hose joining them together -- so if you only use one fuel tap both carbs get fuel

i always use solid black hoses - all the clear / braided i have used goes hard fairly quickly

 

[Rod Rocket]

when you say your carbs have two attatchments for hoses - i assume you are refering to the double banjo fitting at the bottom of the carbs bolted to the float bowl ? -- these are both for fuel -- you will have a fuel hose from each tap on the fuel tank to the "outside" hose connection on each carb - then the inner connections have a hose joining them together -- so if you only use one fuel tap both carbs get fuel

i always use solid black hoses - all the clear / braided i have used goes hard fairly quickly

Thanks Wol.

Spot on with your interpretation.

All makes sense.

I'll go with the solid, although I thought the advantage of the clear would have been to allow a visual of unobstructed flow of fuel??

 

[wol]

I agree on the visual - but when they go hard its a right PIA if you need to remove the carbs to work on them ! -- i believe there is clear pipe that does not go hard but no idea what it is

 

[Rev]

For show bikes clear fuel lines will suffice.

For everyday riding I use solid rubber hose.

This is why.

I put a section of clear fuel line in the vice & put a match to it.

It burned through in 6 seconds.

 

[DAVE M]

I use black rubber both on the tap-carb-carb-tap line and the balance tube

The fuel link ensures both carbs get fuel from either side
The manifold equalises fuel vapour before the cylinder

 

[StuartMac]

Hi,

I must have show bikes, I've used clear braided hose both from taps to carbs. and between carbs. on multi-carb. bikes, for decades. As said, if the bike conks out for no apparent reason, confirming fuel flow from the tank is a momentary check with a Mk.1 eyeball. Clear braided does go hard but dipping in boiling water softens it; worst case, it's that cheap (at least here) that replacing hoses that can't be refitted to tap or carb. is hardly going to break the bank ...

Only extra check I make since the advent of effinol is a short length of any from a new source dipped in petrol for a period to ensure it won't be affected. Although British super unleaded is usually effinol-free given the informed choice of brand, none of the suppliers guarantee it less than 5%, because it's transported alongside premium - which can have up to 10% - and can be dispensed through the same pump. And I could be stuck somewhere where I have to buy fuel with effinol.

manifolds have hose attachment points for a balance hose.
Amal Concentric Mark 1's each have two hose attachment points, presumably one on each also being for a balance hose.

As said, carbs. connected together is so both carbs. can draw fuel from whichever tap is open (originally main only on the timing side, reserve on the drive side). Aiui, manifold balance tube simply reduces the severity of the pressure pulses in the inlet tracts.

Hth.

Regards,

 

[Old Cafe Racer]

No need for clear hose, just depress the ticklers... either there is fuel flow or there isn't.

There is a bit more to the manifold balance tube than that... blank it off and see.
The idle speed will drop substantially and the motor will be slower low down as air/fuel gets sucked from both carbs through it in effect it parallels both carbs

I wouldn't have believed it if someone had told me that, but I built my motor without one and got a very pleasant surprise when I eventually fitted one, re-tuned for it and received a small performance boost.
I even went to the trouble of boring the manifold hose spigots out to the max to capitalize on the effect.
I've always wondered if I could bore them out to 3/8" and still get it to idle low enough..... one of these days.....

 

[Adam M.]

You can have better quality clear hose in GB than we got in N. America, my clear, reinforced hose got hard after first season + winter and from the next one I used only black fuel hose which quality also isn't very high comparing to original Honda fuel hose I remember from seventies.
It's difficult to give any advice because we don't know what hoses RR got down under.
For oil lines I always used black reinforced rubber hose.

 

[DAVE M]

Afaik andy Gregory/tricor England uses both in his premade assemblies

 

[Old Cafe Racer]

If you must have clear hose then get it from Tygon in the States.
For oil lines I use auto transmission cooler hose.

 

[c317414]

I use the clear fuel line that's distributed by JRC Engineering. It will harden but it takes a few years to do so. At that point I make new lines using new ferrules and a crimping tool.

 

[Redmoggy]

I've had the clear un reinforced hose from TriCor fitted to my TR6 for 12 years and 25000 miles. Aside from being a bit yellow it perfectly fine.

Rod

 

[TR7RVMan]

Hi RR, It depends on your fuel & clear hose.

I did much experimenting on my bike with clear. None I could find in the USA would withstand 10% ethanol fuel. All would go hard.

In my experience the TriCore hose set goes hard same as the others, maybe not quite as fast. I'm sure it would lead to cracked fuel tanks. Very disappointed as they looked factory.

New old stock Triumph goes hard on California fuel too.

At the same time most of the clear has a very low melting temp.

I'd love to use clear, but had to give up on it. Maybe in UK or AU it works out ok.

I've experience with Tricor, Moose racing, Tygon (2 types), Motion Pro, various no name brand. None was good. Most was dangerous due to low melting temp. On 100f day was like a noodle, until it turned into hard plastic. It will fracture once hardened has well.

Braded is probably stronger, but plastic is the same & acts the same as non braded on what I could find in USA.

There is fuel rated in blue or yellow, I didn't try those. I have 5/16 lines which limits selection to a degree.

I would love to use clear hose. I like to see the fuel. Makes me feel secure, even if it doesn't really matter.
Don

 

[Rod Rocket]

Thanks Guys.

Ethanol sounds pretty nasty stuff.
Over here it's illegal to add Ethanol to ULP (91 Octane unleaded) & PULP 95 Octane premium unleaded.
It's offered in E10 which is a 10% blend.



I picked up both braided clear & solid black hose for the fuel system from British suppliers.


I'll play around with them with the advantage of replacement parts should my first choice deteriorates.

 

[rambo]

I use black reinforced rubber fuel injection hose normally sold for car use.It will last about 15 years with no deterioration at all.Not much else would be any better.I watched a lovely old Panther completely burn out after a small drip of fuel ignited which had dripped from the carb.Within 10 seconds,the clear fuel pipe from the fuel tank had melted and fed the fire to a point where it could not be put out at the roadside.A total loss of a 1930s 250 model.It had been restored so cant imagine why it had clear fuel line fitted.