Honda XRV Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter #1
My tidying-up/refurbishing of my newly acquired 2001 TA 650 has reached the point where the tank can soon go back on. So set to cleaning it and immediately noticed something amiss.

There are two unions at the rear underside - a larger and a smaller.

165233


The larger one had been bunged up with a brass plug (shown sitting on an aerosol can). PTFE tape had been wound around it and it was quite tight fitting. As soon as it was out, a small quantity of dirty black water flowed out. This didn't look like a Honda fitment to me!

165234


A check of the workshop manual info on tank removal says "Also disconnect the overflow and breather hoses from their unions on the tank" so I assume these two unions are those. Which is which? My assumption is that the larger (the bunged one) is the overflow? I only recall disconnecting one hose here when I removed the tank about six weeks ago.

I have checked the hoses at the rear of the tank. I have a single small diameter hose (which would only fit the smaller union) which then runs into a plastic T-piece (more of a Y shape). Coming off of the T-piece are two more hoses, one which runs more-or-less horizontally back to a securing point on the side of the tool compartment where it seems to be vented to the atmosphere. The other hose runs down into the area of the centre stand. I assume this hose simply drains fluid to the ground.

There is no other hose that would be the hose that joins onto the larger union.

Can anyone make sense of this?

What set-up should be there?

Once again, any advice is much appreciated (and wouldn't be sometimes like to be able to sit down with the previous owners of our bikes and quiz them on the bodge-ups they have done?)
 

·
Registered
Joined
·
23 Posts
Discussion Starter #3
The smaller one is certainly of the same size as the bike's vacuum lines but I don't think it is a vacuum connection.

I haven't checked (and I'm not heading to the garage right now because it is a winter's evening here, with sleety snow in the air!) but other Hondas I have owned have had a drainhole in the recess of the filler hole. Presumably this drains any spill when refilling or any water that gets into the recess. A line must run inside the tank from the drain hole to the outlet point on the bottom of the tank. I am assuming this is what the plugged larger hole was.

I am assuming the smaller hole is for the tank breather. Presumably the hose running down as a drain is for any fuel that gets spat out the breather.

I guess I'm looking for confirmation of this theory.

Also, why would a previous owner have plugged it? What would be the point? If the hose had simply come loose and been lost, wouldn't it have been easier to simply replace it rather than undertake the plugging of the hole?

Am I missing something?
 

·
Registered
Joined
·
2,800 Posts
 

·
Registered
Joined
·
8 Posts
Mines 2001 as well so when I get back this evening I'll have a look if it's not sorted by then.. I can't help notice the PTFE tape and wonder if the original fitting was leaking etc....I notice I don't have a petcock, it couldn't be for one of them could it?
 

·
Registered
Joined
·
23 Posts
Discussion Starter #6
ds99, I think you have hit the nail on the head! Makes perfect sense now.

As far as I can tell, the inside of the tank seems fine. And certainly no rust particles when I drained it. But perhaps the drain pipe from the filler recess has a hole in it and that is why it has been plugged.

The downside to simply re-plugging it is the very point made in that thread - if the recess can't drain and it gets water in there, when you take the fuel cap off, the water will go straight into the tank.

Any suggestions?
 

·
Registered
Joined
·
23 Posts
Discussion Starter #7
Been thinking more about this.

When I unplugged the hole, a small quantity of dirty black water came out. It did NOT smell of petrol. I would have thought, should the proposed theory be correct, that any fluid in that tube would have been petrol. I did give the bike a really good wash down when I got it back home after purchase. This water would be consistent with a small amount of water getting into the recess during the wash and running down the drain hole.

I also would have assumed that the drain hole in the fuel cap recess would have been plugged. I have just checked and it isn't. I also had another check inside the tank (as far as I can) and it looks clean as a whistle. There were definitely no rusty particles in the float bowls or the inline filter that had been installed by a previous owner (I didn't see the fitment of this as suspicious as I always installed a filter in the fuel line as a precaution on all the carbed bikes I have owned). I also drained the carbs when I started the refurbishment. I drained them into a glass jar and checked for water. There was none.

Also, while looking into the tank with a torch I caught sight of what I assume was the drain tube and it looked like copper.

Here is my proposed test:

I will set the tank up securely and slowly pour petrol into it. I will monitor the (unplugged) drain hole to see if petrol runs out of it. If the tank is full and no fuel is flowing from the drain hole then there can't he a hole in the drain tube (and there must be another explanation for its plugging).

I'm no scientist so can anyone see a flaw in this?
 

·
Registered
Joined
·
2,800 Posts
the tank has never been off mine so i don't know anything about these holes/drain lines!
 

·
Registered
Joined
·
23 Posts
Discussion Starter #9
Have been reading online how this is a problem on many bikes, not just Hondas. The tube inside the tank is probably copper so shouldn't corrode. However, sometimes a fuel pump nozzle gets pushed in too far and can nick the tube, causing pinholes.

Some say just to plug both ends. Some say the tank is scrap and should be replaced. Others have had success with cleaning out the tube and pushing through thin diameter fuel-resistant hose coated in fuel-resistant epoxy glue. It basically lines the tube. There's also a YouTube video of a guy replacing one with another copper tube and soldering both ends.

I think I will still try my experiment before going any further, just to see whether it leaks.

I will investigate further and report back.
 

·
Registered
Joined
·
7,694 Posts
I seem to recall it being mentioned in the past that the filler neck drain can get blocked then rot as it goes through the tank, meaning the tank leaks fuel from the drain when full(ish).

Put a finger over the hole at the neck, blow on the large stub, if air escapes you have the answer.

Sent from my SM-A320FL using Tapatalk
 

·
Registered
Joined
·
23 Posts
Discussion Starter #11
I did my "experiment" today.

I set up the tank on trestles. I sprayed brake cleaner into the drain tube inlet and it flowed straight out the bottom - so the tube is not blocked. I then filled the tank to the brim with petrol. There was no leakage from the drain. I monitored all day and still no leakage.

That suggests one of two things:

First, the drain tube is intact and the plugging was for some other reason (although I can't think what).

Two, the tube does have a hole but it has become plugged up with gunge since the drain was plugged, so is temporarily fuel-tight. However, if the tube is not blocked (as I established), how could a hole become gunged up?

I am now in the process of getting in touch with previous owners to see whether any of them can last any light. The person I bought it from knew nothing about it and said he never had the tank off. I believe him as he didn't own it long. But he has given me the phone number of the person he bought it from and, according to its Certificate of Registration, this person owned it for a while. They may be able to explain the plug.

I will update when more is known.
 
1 - 11 of 11 Posts
Top