Replacing Oil Breather Hose

[dlaing]

There is a large hose running from the top of the engine to the bottom side of the top of the spine frame.

The hose is about an inch in diameter.

It is part 18 of drawing 10 in the parts catalog CD.

Does anyone know the exact size?

Ideas about where to get a better quality replacement?

Mine has started to break down and is leaking.

This may be something for people to keep an eye out for.

FWIW I have 21,000+ miles on the bike now.

[RichMaund]

I replaced mine with 3/4" ID heater hose. You'll have to add in a couple plumbing 45 degree elbows for the bends.

The stock Guzzi hose is cheap vinyl. They breakdown ususally in two years or less in use. The rubber heater hose lasts much longer!

[dlaing]

Thanks Rich,

Do you recall what type of plumbing fittings you used?

Copper, PVC, ABS?

I'd guess half inch copper 45 angles would do the trick,if the copper OD meets the rubber ID.

And what the heck, rather than run three sections of rubber hose and six hose clamps, I could run two sections of rubber hose, four hose clamps and a copper pipe between the 45 degree connectors.(so much for weight reduction)

Wish I had a pipe bender, but I guess I could rig something up, like bending over a large round rock, or maybe a few more 4 degree bends, if needed.

Or maybe copper flex pipe like what they attach water heaters with. but then I might get into a mess with the fittings...or not.

[RichMaund]

I used 45 degree white pvc fittings. They fit into the hose nicely. Then I used heavy lockwire in leiu of bulky hose clamps. You can even dab some black liquid vinyl over the joints to make them even less obtrusive.

[dlaing]

cool! PVC will keep the weight down.

[RichMaund]

Actually, I'd have been happy to use copper, but it fit's too loosely inside the hose.

If you have a conduit bender, you could make a very nice hose with the bends in it and just use a pair of rubber hose sections to join it to the fittings on the frame and engine.

Not being an electrician, I haven't needed to bend much conduit over the years. But the benders are so inexpensive, I'm considering it. Great fodder for custom plumbing like this!

[dlaing]

Yah Rich, the copper is just a little too small, while the outside of the half inch schedule 40 PVC pipe is a perfect fit.

So what you need is 3/4 inch or 19mm Inner Diameter heater hose, a total of four hose clamps, a few inches of the 1/2 inch pvc pipe, and two pvc elbow connectors.

I used one 45 degree angle connector at the bottom and a 90 degree angle connector at the top.

Arrangements with variations of 45 and 90 degrees will work.

You will need to PVC cement in the 1/2 inch pipe to all ends of the connectors. (unless you find connectors with male fittings.

The 90 degree angle at the top fit pretty snub against the coils. A tight fit, but it works.

Getting to the hose is not as difficult as it looks.

Just take the fuel tank off,

loosen up the coils (no need to remove the coils),

loosen the hose clamps,

yank off the hose,

and reinstall the new hose assembly.

My hose started cracking at the upper bend just above the coils, so be sure to inspect it there.

 

EDIT Read to the end of this thread. there are problems with the PVC pipe, and better solutions available.

[dlaing]

Jaap, perhaps this could be moved to "How to" and retitled "Replacing Breather Hose"

Thanks!

[Admin Jaap]

Done

[jrt]

Nice. Timely post. I just took my tank off- a lot of the insulation material had started to come off <_ and i gluing it back. this looks like a good preventative maintanance project. src="%7B___base_url___%7D/uploads/emoticons/default_luigi.gif" alt=":luigi:">

Thanks for the info

jason

[RichMaund]

Looks much like the one I made for myself! But I didn't like the white PVC fittings showing, so I dabbed black liquid vinyl over them.

Mine cracked above the coils as well. Any chance the coils produce ozone or something to rot the hose out?

[al_roethlisberger]

Dunno about the coils->ozone but there is a lot of heat in that area, and the bend probably gets some torsional movement/stresses as the engine revs, etc... so... Maybe it's just a function of it's location...

 

BTW, this is a great solution. But here's a comment... can one find some sort of "clip" clamp like is often used on fuel injection lines that is less obtrusive than the spiral hose clamps in the photo above? I would assume so, but I've not found any easily. I just hate using spiral clamps for something that rarely if ever gets taken off(like the joints in this kit) and the darned things end up cutting you(or hoses/wires) with their damned razor-sharp tongues sticking out after tightening So I'd like to minimize the number I have employed under the tank... and I already have quite a few

 

I'll have to check my "Summit Racing" catalog and local BMW dealership for such an animal methinks

 

al

[RichMaund]

I used heavy SS lockwire on mine. Almost disappears under the liquid vinyl!

[Gio]

Thanks for the heads-up guys - I checked my breather hose and also found serious cracking at the top end (~35,000 km).

 

To make it a little easier for others, here are hose lengths I used with Rich Maunds "heater hose and PVC" method :

 

From the top (ie spine connection)

 

1. Angled cut on top end (2" at front, 1.75" at rear) - allows better fit

2. 90 deg elbow

3. 12" central length (I measured 12.5" based on the orig pipe but it was too tight)

4. 45 deg elbow

5. 1.5" to the engine

 

I used 1.25" lengths of 0.5" pipe for the elbows which left 0.5" sticking out for connection with the heater hose.

 

As dlaing says, it's tight but it works.

 

Gio

[dlaing]

Some bad news.

My fix did not last.

I developed a leak.

The upper PVC joint is fine, but the lower joint gets too hot, deforms and the pvc cement seal breaks down.

So, I am going to look for a better solution.

Possibly brass fittings.

Half Inch ID brass pipe fits the hose fine. I just need to find a 45 degree angle coupling with the right solder joint or threading...

Will let you all know what I come up with.

FWIW I may not have primed the pvc before gluing, so that may have been one reason it failed. But the pipe got hot enough that it deformed enough to compromise the seal against the hose.