V7II final drive vent

[guzzi4me]

Greetings All!

After doing a search on this subject I ordered the banjo bolt and have some vent line.

Going to run the line up under the side cover. Should it not have a filter of some kind at the
end? Was looking at a few air/fuel filters but they all seem rather big.

If a filter of some kind is needed was thinking of this one....

https://smile.amazon.com/gp/product/B0064MV6ZG/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

Just thought I would gather some opinions from the great resource that is WildGuzzi members!!

Thanks,


Jeff

[Solorider73]

We had a similar discussion going a few days ago.  The comment was made how BMW GS handle water crossings. I found this tube with a pressure bulb that is sold by touratech. Moves the vent higher up on the bike. No filter required.

https://touratech-usa.com/Store/Final-Drive-Breather-Relocation-Kit-BMW-R1200GS-ADV-2010-on-Oil-Water-Cooled

[egschade]

I think that routing the vent tube under the seat area and enuring it's protected/pointing down would be sufficient. It's not like an engine constantly sucking large volumes of air that requires filtering.

[guzzi4me]

I think that routing the vent tube under the seat area and enuring it's protected/pointing down would be sufficient. It's not like an engine constantly sucking large volumes of air that requires filtering.

True!

I'll just do a nice easy loop and point the end downward. Saved me $6 on a filter! Guzzi content....

Thanks!!

Jeff

[GonzoB]

This thread inspired me to tackle my Breva 750 vent:



I drilled and tapped a 1/8" pipe thread in the vent body and installed a pneumatic fitting. It vents up under the right side cover. Should stop the occasional drip of oil from going all over the wheel!

Gonzo

[Kiwi_Roy]

I have started looking at my V7iii, I bought 4 ft of the smallest steel metric brake line I could find (its about 3/16" OD) $3.50
I will run it along the drive tunnel and bend it up under the side cover, I think there is room for it to move back and forth as the suspension does it's thing without having to use a flexible hose. I haven't been able to find a banjo fitting so I may have to make one of aluminium, a lathe would be nice but hand tools will have to do.
The thread in the top of the rear hub is 10mm x 1.5 and the thread on the flared brake line is 10mm x 1, I have taps for that.
I'm not sure how successful I will be sealing the flare fitting but if all else fails JB Weld is your friend.

[SmithSwede]

More power to you guys.   Maybe one day I’ll join you.   

But I don’t think the vent is where the water is coming in.   Look very closely at the rubber boot on the front of the swing arm.   When I sealed the boot, my water contamination problems went away, even though I continued to sometimes ride all day in heavy rain. 

Even if you wanted to suspect the vent, it seems like the easiest thing to do would be to put a bit of foam over the vent when you are riding through a gully washer.   And leave it off the 95% of time you are not riding in heavy rain.

All these vent lines and fittings and tubing and the associated plumbing and JB Weld seem like crazy overkill.  But who knows?  Keep giving me data. 

[Kiwi_Roy]

SS, you might be right, I put a better clamp on the front of mine, cable ties were never meant for making stuff watertight.
I didn't use gasket cement on the 4 bolt flange but I did apply grease thinking it would prevent water getting in there.
I'm thinking about adding a drain hole at the back end of the driveshaft tunnel, thoughts on that crazy idea?
How did you seal your rubber boot?
I think most of my water gets in when I wash the bike, I go at it with the hose or the car wash wand wherever I happen to be.

[chrisfer]

But I don’t think the vent is where the water is coming in.   Look very closely at the rubber boot on the front of the swing arm.   When I sealed the boot, my water contamination problems went away, even though I continued to sometimes ride all day in heavy rain.

Yes water ends up in the swingarm.
I drilled the bottom of the rubber gasket, just a small hole with the soldering iron for now.
But I'm also thinking of adding a drain hole at the rear end of the driveshaft tunnel ...

[GonzoB]

My understanding of oil seal lip design is that there are two angles on the lip.The steeper angle is on the liquid side and the shallower angle is on the air side. The difference in angles creates a dynamic pumping effect to ensure that the liquid stays on the inside. I've never thought of this before, but what if you have oil on the inside and water on the outside? Does the water get "pumped" in? I think it is likely. If you were designing for water one side and oil the other you'd probably need a pair of opposite-facing seals. I don't know what the MG final drive seal is like, but if water ingress from the drive tunnel occurs, then that may be the mechanism. Sounds like a drain hole is a good idea.

My problem with the final drive vent is that the occasional drips of oil end up on the wheel. Now, after considering other suggestions, SS's foam idea might be a simpler solution. Alternatively, instead of running my breather line up to the side cover, I could have just let it hang down next to the drive housing so that any oil drips just hit the road, not the bike. It's unlikely any water or crud would work its way in.

Gonzo

[Kiwi_Roy]

I read that there is no seal on the driveshaft input, if there is any buildup of water at that input it can run straight in but it should be possible to seal the boot, perhaps with some non setting gasket cement.
I'm sure SS will get back and let us know how he sealed it.
If you look at the Vent seal fitting it has a ball check fittings assuming that is free it will let pressure out but if it seals properly when the hub cools down it will create a partial vacuum, this would have the sect of sucking any water build up at the input shaft right into the box. I think tomorrow I will loosen the 4 bolts at the flange to see if there is any water laying in there.

[GonzoB]

I read that there is no seal on the driveshaft input,

Hmm....My Breva parts manual shows part no. 38 a "Gasket Ring 32x47x10" on the input shaft. The picture is not very detailed but it looks like a seal (??). Is that not on the later models?

Gonzo

[Zoom Zoom]

Roy, check out Summit Racing. Lots of banjo fittings.

ZZ

[chrisfer]

I think tomorrow I will loosen the 4 bolts at the flange to see if there is any water laying in there.

Water also stagnates at the bottom of the rubber boot.

[SmithSwede]

I took my boot completely off the swing arm.  There is a circlip on the inside that holds the boot on.  It did not seem installed correctly from the factory because the rubber was bunched up leaving a gap.  I removed the circlip (which was a bugger).  Then slathered sealant on the inside of the swingarm and installed the circlip correctly.  That seals the back end.   Then I put a very light coat of sealant on the other end of the boot where it mates to the transmission and is secured by the clamp.  That seals the front end.     

That resulted in an airtight seal!  When it got warmed up, the boot would swell up like a balloon.  So I used a red hot sewing needle to put a tiny vent hole in the boot.  Now it is watertight but doesn’t swell up. 

My problem was I would get a surprising amount of water in the swingarm.  I’m convinced the water sits against the seal on the final drive and makes its way in.   Now I don’t get water in the swingarm and the final drive oil doesn’t come out water contaminated. 

I also slather a bunch of grease all on the outside of the final drive seal lip, just in case some water or condensation does get in. 

I have been tempted to drill a small hole at the rear underside of the swingarm.  That makes sense to me, and I probably would have done it if I kept getting water in the swingarm.  Since I don’t, I didn’t drill the hole. 

I’m not sure if such a hole would be a stress riser and a bad idea for a critical component like a swingarm.  I’d be more confident if other Guzzis, or similar bikes, had such a hole. 

There’s no doubt that the little top hat vent is open to the atmosphere, and could permit water ingress.   Even if not rain, I could see humidity and condensation being drawn in as the hot final drive cools down.   It’s probably a good idea to change the final drive oil frequently for this reason alone.   It is only 170 cc of oil, so cheap insurance.

It would also be easy to make a little foam cap and keep it in your saddle bag along with a piece of wire or bread wrapper.   If it starts pouring rain, affix the foam cover over the vent.  I’m sure it could still breath ok but you wouldn’t worry about splashing water getting in.