the filter may need to be turned around
you are filtering air going out

You know a 1/2 psi check valve my help it to burp instead letting it flow both ways just a thought
speed

Look through this entire thread. There are pictures that will show you where the vent is located.

Rand

i have the full pull start case off. is the vent hole behind the the sprocket that is exposed??

Yes, here is the picture that was posted earlier.

Bob

THANK YOU right now my brain is one dimentional an all i can remember is seeing the sprocket when i took off my pull start this past weekend to get it repaired. what size machine screw is used to plug the hole??

Thanks Speed, i will turn it around. I got all the crank seals changed today, and went out and rode it for about 20 minutes tonight and it did fill the filter with oil about 3/4's of the way up. I am not really familiar with the check valve, can you tell where to find one?

Thanks,
Nick

Im wondering if the vent in the cap places the tube/hose in a direct line with the oil splashing off the gears and forcing the oil up so far???

I don't think so Turbo, I believe Speed has a mod similar where he modifes the case by welding a block and a nipple in place just slightly above and in line with the stock dip stick and there is no issue. Well at least none that I have heard of.

It all has to do with the size of the line that is used to vent the case. If the line is too small it won't allow the oil to drain back into the case and the building pressure forces the oil up and out of the tube.

You either need to run the line with a filter in place or run the bellows like Randy's setup. I believe this is what I was running when you came out to Walker River. Like I posted, I tried a smaller tube with just the vent and had the same oil puking problem. The air has to have a place to escape when the pressure is building. With the filter in line it allows the air to escape past what little oil has been initially forced up the vent tube by the expanding air.

Rand

speeds vents were just like Racerats on the side of the gears...
I will try the bigger tubing..

My apologies Speed!!! Who was it that had them on the side??? Randy maybe...

Hey Speed, what sized nipple are you using for your case mod?

Rand

1/8" npt with a 1/4 hose barb

speed

I was reading Randy's instructions dated 9/23-2003 for his vent modification. He has posted 2 different nipple installation location set ups. One modification is done the way that Speed's cases are modified (drilled from the top) and the other modification is done by drilling and tapping the side of the case. Note the comment bellow he has made for the modification where he has drilled the top of the case as in the picture below.

Randy states....



So it is necessary to use the fuel filter in line if you are going to use the open vented type modification. I originally did not have the issue of oil traveling up the vent line because I used the sealed (expanding bellows) type modification.



If you are going to use the sealed bellows for the vent modification Randy States.....

Quote:

If you are going to use the rubber bladder for a sealed system leave the fuel filter off.

So there you have it from the expert Randy Bridgewater who originally designed the system.....when using a top or side mounted venting setup, a filter needs to be in place for the open vented system and no filter is required for the sealed bellows type system.

Rand

so what do you guys think is a better system to use. sealed with bellows or unsealed with filter...

i noticed on my last quad rally that i went on, that alot of diffs on the quads use a bellow style vent system..just food for thought

It all depends on where you place the vent on the Ody. If the dip stick hole is used the ballancer gears throws oil across the vent hole and up the hose. With this setup, I would use the bellows system. If you vent the side of the case by tapping a hole and threading a fitting into it then you can run the filter with the end of the hose vented. Either way works but I prefer to have the system sealed to keep water and dirt out. I am running the dip stick vent so I am using the bellows system.

What brand of quads were you seeing the bellows vents on? I think the bellows I am using now is too stiff. I would like to see if they are more flexible then the one I am using.

Rand

not sure what quad it was on. only reason i noticed is caused the guy rolled it and i help load it in the back of a truck

My wife has a 2004 Suzuki Vinson. I cannot get a pic right now as it is in storage, but it uses a bellows type breather on the diff.... http://www.partforyamaha.com/pages/part ... uzuki.aspx" .".. ...if the link works, it is part number 67 in the diagram, SKU: 27491-38F00
CASE, BREATHER

In case I ever loose my dipstick here is the tape so I can use a zip tie!

That's a good handy in the field check if you loose the dip stick! If I read that tape right then 3" is the upper level mark. If you loose the stock one and are too cheap (like me) to buy a new one then you could just modify one of the Ford radiator petcocks by gluing a piece of rod into it and Bob's your Uncle!

Rand

Thanks Lonerider, I am wondering how pliable the rubber is. The one I am using is pretty stiff but so far it works well. Attached are pictures of the final modification I have done.

Rand

Ok time to revisit this one so what is the perfered method of venting?

I need to vent a 350 case that is on my bench I have already installed a screw in the vent hole so it can no longer vent into the area where the flywheel is.

I am wondering if I can just drill a small hole down the top of the factory dip stick about .060 in diameter, go in about 1" from the top of the stick then drill one horizontally to connect to the hole drilled from the top, volume of exchange cant be that much?

I am leary about plugging the hole on the other side or magneto side... IF your vent gets plugged up wont this create back pressure that will blow out a seal??? Randy shows his method is to plug the hole on the balancer gear side, so if there is blockage it wont cause an air leak in the seal behind the balancer gears...

I thought the same thing too but from all of the information I have seen and from what I have experienced, oil gets pushed up through the vent tube. Unless these is an area for the expanding air to bypass the oil (such as a large filter) traveling up the hose, the expanding air pushes the oil up and out of the top of the hose.

The other thing I have discovered is that the smaller the hose the more likely that the oil will travel up and out of the hose. A large hose with a bellows seems to work best.

I have converted both of my Ody's to the expanding bellows and they are working well so far.

Dave (Turbo) had an issue with the ease of removing the tube for oil level inspection and I have solved that problem also. I will post some detailed pictures of the latest revision when I get home tonight.

Rand

Dave, I have covered that issue also. I have just a small hose leading from the factory vent with a small diffuser in the end of it. It has a 40 micron filter on it which is about .0015" which should be enough to keep the crap out.

Rand