Sump Breather Hose Delete?

[swooshdave]

 

Reed valve breathers are the simplest way to reduce the crankcase pressure.

 

 

I have been advised by esteemed sources as well as from some forum crawling that power brake booster check valves work well.

Brake booster valves are usually flappy pieces of plastic. Engine pulses are quite rapid, several thousand times per minute, and will wear out or destroy a plastic valve.

 

If they worked that well why do no manufacturers use them for crankcase evacuation?

 

The caveat is that V-twins even the pulses out somewhat, especially compared to a 360 twin or a single.

[sp838]

Brake booster valves are usually flappy pieces of plastic. Engine pulses are quite rapid, several thousand times per minute, and will wear out or destroy a plastic valve.

 

Fair point. I'll have to ask those who have recommended them what they think about that.

 

 

 If they worked that well why do no manufacturers use them for crankcase evacuation?

 

Generally speaking, the answer to questions like this is: money. The bikes that roll out of the factory aren't the best they can possibly be, they are only sometimes the best the factory can put out for the price point in the market they are trying to sell them at. For example, the frames on our bikes aren't made of chromoly or 7075 because they'd be too expensive if they were. The bodywork is nylon, not carbon fiber. A Yugo has four wheels and an engine, but it's not a Ferrari. Adding a check valve to the breather is an added expense in terms of sourcing the part, as well as in additional assembly steps at the factory. Because Guzzi opted not to have one doesn't mean the bike wouldn't benefit from it.

 

Anyway, I am now looking into the "race" crankcase breather valves made by aftermarket Ducati part manufacturers. There are some sexy ones out there, but they cost about ten times what the brake booster check valves cost, of course... 

[swooshdave]

Yeah, unfortunately most of the aftermarket breathers are marketed for Ducati, hence the horrible prices. And they're probably shipping from China and cost $5 to make.

[Chuck]

Yeah, unfortunately most of the aftermarket breathers are marketed for Ducati, hence the horrible prices. And they're probably shipping from China and cost   to make.

FTFY..

[docc]

Again, why not use the check valve common to other Guzzi big blocks?

 

And why was that eliminated from the V11 anyway?

[sp838]

docc, what years/models are you thinking of?

[docc]

Seems like when I replaced my breather hose there was talk of a check ball, but mine didn't have it and no other V11 owners reported one. I think I saw it in a diagram, so maybe the 1100 Sport/ Sport 1100?

[sp838]

If I'm looking at it right, the parts diagrams for our bikes just show the big hose coming out of the back of the top part of the case, with a few hose clamps and a plate that holds it in place. I'll go look at the drawings for the older 1100's.

[docc]

I found moto fugazzi's 2013 post showing the valve. Check it out:

 

http://www.v11lemans.com/forums/index.php?showtopic=18186&p=193003

 

And guzzimoto's explanation here:

 

http://www.v11lemans.com/forums/index.php?showtopic=18243&p=193842

[Tinus89]

Interestingly, my 2001 V11 Rosso Mandello doés have a check valve in the crank breather... But it's not on the parts drawing.
So maybe the P.O. put it in, or maybe it was there from the factory.

[moto fugazzi]

My 2001 and 2004 didn't have the check valve. I talked to the original owners, and they say they never removed it. My local dealer in northern IL said the check valve isn't really needed unless you do many short rides that don't fully heat up the engine. 

Ken

[pete roper]

Oh for @#!#$#'s sakes.....!

[68C]

Still don't understand why you want to remove this pipe.

 

It was common to fit a LeMans Mk1 breather box to the 850T3 which let oil run back to the sump but allowed gasses to vent to atmosphere and not into the airbox, less chance of oil deposit build up on the inlet valve. The metal box was about 3" x 2" and sat between the carbs, it had an internal rubber flapper valve which ensured a low pressure in the crankcase, worked really well and lasted a long time. As the original airbox would not fit you then fitted K&N filters.

 

I can understand if you want to reroute the pipe that goes goes to the airbox but not why you want to stop the oil running back to the sump.

 

Of course, allowing the gasses to atmosphere has an enviromental effect which is why the OEM choose to burn them through the engine.

[sp838]

Thanks for all the input guys. Seems like Guzzimoto's post which docc linked to above explains it best. PCV + return line is no good because the engine will attempt to suck air through the return line. So it's either PCV + remove the return line (maybe have it go to a catch bottle) or keep the stock setup. I'm guessing Guzzi eliminated the ball valve because it probably didn't work very well and let too much oil by. The return line makes sense from a maintenance standpoint.

 

It wouldn't be too hard to have two setups and compare them. Stock, and one where a valve was put in the crank breather hose and the return line went to a bottle. It's all bolt-on stuff.

 

68C, I was asking mainly because I am always curious about ways to reduce the amount of clutter of hoses and wires and extra fittings etc etc on the bike, and it looked like a possible candidate for removal if in fact it wasn't crucial to the operation of the engine.

[docc]

I was asking mainly because I am always curious about ways to reduce the amount of clutter of hoses and wires and extra fittings etc etc on the bike, and it looked like a possible candidate for removal if in fact it wasn't crucial to the operation of the engine.

Occam's Guzzi !