Stray Hose

[Cadbury64]

I had my carbs and airbox out to get access to the front cylinder valves last night for manual CCT installation. Upon reassembly I have one small stray hose, about 7-8mm diameter. Looks to me like the Water Bypass Tube in the hose diagram,
[img][IMG]http://i629.photobucket.com/albums/uu15/Cadbury64/Hoses.png[/img][/img]
but I don't know where this should connect to. The loose end terminates beside the front carb on the right side; I fed it through a hole in the plastic shroud during reassembly. The hose is then bundled with others behind the right rad and head downwards from there so I presume it is some kind of overflow/drain. Any suggestions? I have started the bike up for a few minutes and no sign of leaks or other misbehaviour.

[Wicky]

Check to see if you have a vacuum take off plug installed on your front pot. As a hose (usually 4–5mmID) can attached there and used for balancing the carbs and /or running scotoiler.

[Cadbury64]

Thanks Wicky, but its not that. I fitted a vacuum take-off line there myself last night, and removed the OEM socket head bolt and washer to do so.

[Wicky]

What's the internal diameter of the 'stray hose'?

[Cadbury64]

I'm at work now but my recall is 5mm id, about the same as fuel tank vent and bigger than the vacuum for the fuel tap.


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[darkember]

Humm you didn't take photos as you stripped down. Is you bike the old or later model?

[Cadbury64]

1997 model. The hose tees into the fuel tank vent hose (the smaller dia one at the right rear of the tank) just below the RHS rad, this line then drains under the motor.


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[Cadbury64]

Do I win any sort of prize for posing an unanswered question???

I still can't figure out where the hose should go. It's clearly an overflow drain for something, as it tees into the fuel tank vent, and terminates under the motor. At present I just have it sitting loose under the carb above the plastic guard.

I've just ridden for 160km and there's no sign of any problem/leaks.

[VTRDark]

The hose tees into the fuel tank vent hose (the smaller dia one at the right rear of the tank) just below the RHS rad, this line then drains under the motor.

Sounds to me like an old vacuum take off for carb balancing or for running a Scotoiler or something. It should be capped off.

(:-})

[Cadbury64]

Thanks for that response Carl but I'm sure it's an OEM part. It's shown on the hose diagram on page 1-22 of the manual, where the arrow head for "Water Bypass Hose" is shown, it's the smaller hose that disappears up behind the frame spar next to the coolant tank. I've added a bit of red to the diagram to show the hose, if you know where this is going please let me know!

[VTRDark]

Sometimes those diagrams really don't help. I know what's down there. You have the hose from the rad cap that attaches to the base of the expansion bottle and then at the top, which is likely what you have dangling around, is the coolant overflow hose. This runs from the plastic nipple at the rear (if facing the bottle from the cap side) down through the frame on the left around the gene cover and hangs down by the fuel breather and overflow somewhere behind the oil cooler line.

I think your coolant overflow hose has popped off the nipple. There should be a little tiny compression ring on the end of the hose to hold it in place. Generally this is not needed and the hose is a tight fit requiring a dip in boiling water to expand and slide on into place.

(:-})

[Cadbury64]

Thanks again Carl.

I'll take a look at the coolant overflow and check if there is a hose attached. As I said, after a decent ride there's no sign of any leak and the connection to the fuel tank breather suggests that it is some sort of drain/overflow/breather, so you're probably dead-on with the expansion tank overflow suggestion.

I'm only chasing this due to OCD...

[Cadbury64]

I've confirmed that there is a clipped hose attached to the coolant tank overflow beside the filler cap, so my "mystery hose" remains just that for now.

[VTRDark]

So one end is not connected. Where's the other end? Come on you should have worked this out by now It may be a dead hose and can be pulled out. The reminiscence of something.

(:-})

[Cadbury64]

Yeah, maybe I'm flogging a dead hose?

I do know where the other end is connected (T connection to the fuel tank breather) and it appears in the service manual, just without any clue as to where the other end goes...