Re: [ST] What does the...

[Andrew Tait <antait@xxxxxxxxxxxxxxxx>]

Hi there,

Rupert Galea wrote:
>>I have just finished a spark plug, filter and oil change and putting
>>everything together I noticed that the pipe running to the fuel tank,
>>called the fuel pump pressure hose (or similar) in the Haynes manual,
> 
> is
> 
>>really badly perished and has cracked in several places.  Obviously
> 
> it's
> 
>>not going to be pressurising anything!
>>
>>Does anyone know the function (apart from the obvious) of said hose,
> 
> and
> 
>>the ramifications of it being so damaged?
> 
> 
> Andrew,
> This post made no sense to me but I received my Haynes manual today and
> now it does (page 4.4).
> 
> Are you talking about the hose that Haynes calls the Fuel pressure
> regulator hose? If so my bike has never had a hose connected to this
> outlet on the tank! Can you tell me where the other end of this hose
> connects?

Page 4.4 exactly.  I'm hoping that someone hasn't just removed it at 
some point noticing that it was perished and the bike was still running. 
  It might be worth checking with a Triumph dealer to see just how 
necessary that tube really is.

The other end of the hose connects to a stub on the side of the airbox 
about half way down the right hand side.  OK, I can feel the pain 
already, but I changed the oil with Castrol R4 (5W-40), put in the new 
plugs, and replaced the hose with a piece of rigid, solvent-proof 
tubing, schnaffled from work.  I chopped two short pieces of the old 
hose to connect the rigid hose to the fittings at each end, as the new 
hose is thinner walled and slightly narrowed I.D.

The difference in the bike's running is staggering.  Having seen the 
recent comments on 5W-X oils, I was really watching the gear shift on my 
first decent run last night, and when it stuck on an upchange at about 
6500rpm, I thought "Oh-oh", until I realised I was in 6th gear and doing 
something silly like 120mph.  There WAS no upchange, and the power 
delivery felt about the same as it did before at perhaps 95mph.

Anyway, either the new plugs (old ones looked immaculate after 5800 
miles) or the new tube, or perhaps the new oil, or a subtle combination 
of all 3 are responsible for the ST running better than it ever has 
since I got it.  In fact, it's like getting used to the bike all over 
again, especially about 6000rpm.

> Also last time I put my tank back in I was not sure if the return hose
> was supposed to be routed under the hump at the back of the tank or in
> front of the hump. I routed it around the front of the hump. This
> stopped it rubbing on the bottom of the hump, the frame and interfering
> with the fuel gauge sender wires. However it makes things a bit tighter
> where all the hoses cross by the flange. The Haynes manual shows it
> going almost straight down which means it would go under the hump. 

I went for straight down, as it was (a) the way the hose was happiest 
without twisting it, and (b) what the Haynes manual showed.  I tried 
pushing it round to forward facing, but as you said it feels a bit tight.

Oh, I've used those fuel fittings before.  The plastic ones.  I built a 
rig at work with water cooling about 12 years ago, and used the self 
sealing female connections throughout.  Absolutely identical to the 
Triumph fuel connections.  We were pulling bits off it today to clean 
and replace them, and I realised that they've probably been connected 
and disconnected at least 4 times a year in that time, and a couple of 
them have much more torsion than the fuel fittings on the bike.  Odd 
that they would ever fail, unless they get slightly brittle in contact 
with petrol, perhaps.

Bed time...

Andrew

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