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Deleting the oil return tank

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Just installed new fcr carb and want o get ride of the oil return tank. I know the motor needs to vent and most bikes have a long hose off the top o the motor to do that. Question is can I block off the lower breather hose at the motor and have the motor vent from just he top

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Lots of folks have tried deleting the tank, but there hasn't been much progress.  Unfortunately it is very well engineered and works very well.  Several years ago, folks wanted to delete the tank tried all manner of changes.  I would not try to vent from just the valve cover.  There is quite a bit of pumping going on inside the little motor.  I would think you can make a different style tank, but you need the tank to allow the engine to be properly vented and not lose oil all over the place.  YMMV

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I ran my vent tube up under my seat as far back and as high as it can go. No issues in 3 years. It gets a little residue in the area but not a issue..

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I have issues with the breather box for different reasons. I eliminated the airboot connection, and extended the hose up to my right radiator with a pod filter. Oil can still creep up there if I wheelie too high for too long. It might be my big bore pumping this thing too hard, but my oil loves to creep up my breather hose. Here my thread, still unresolved.

 

7 hours ago, TLRDoug said:

Lots of folks have tried deleting the tank, but there hasn't been much progress.  Unfortunately it is very well engineered and works very well.  Several years ago, folks wanted to delete the tank tried all manner of changes.  I would not try to vent from just the valve cover.  There is quite a bit of pumping going on inside the little motor.  I would think you can make a different style tank, but you need the tank to allow the engine to be properly vented and not lose oil all over the place.  YMMV

I lose oil with the damn thing on (when I wheelie too high). I think I need a custom one made that can still put the oil back into the crank case at 90°.

15 minutes ago, ohiodrz400sm said:

The tank doesn't interfere with the carb in anyway.

Oil can get in the airboot though.

 

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If the oil tank has a slight leak but you have it vented to atmosphere can that cause issues with the motor running correctly?

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I have issues with the breather box for different reasons. I eliminated the airboot connection, and extended the hose up to my right radiator with a pod filter. Oil can still creep up there if I wheelie too high for too long. It might be my big bore pumping this thing too hard, but my oil loves to creep up my breather hose. Here my thread, still unresolved.
 
Oil can get in the airboot though.
 

Only if routed to the airbox. The E model for example doesn't route to the airbox, it vents to atmosphere
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get a bung welded into your header pipe facing south and route the line to that lol .. thats what i used to do with my hotrods .. its just a breather, the sealed setup is an emissions thing, but it does keep you from losing alittle oil gradually, i doubt its enough to even write home about though changing it at under 2 grand ..

Edited by cowpie

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I've never had a problem with the air/oil separator/return tank. Sure, I'd like to have it not be there but it is not a real issue when working on the bike, it does its' job well. No one I have known has had 'no problems' once removed. They smoked on wheelies and consumed a lot of oil. After a 100 mile ride, they'd have to add half a quart. I consume about 10 ml in 1,000 miles, easily 100 of them at 12 O'Clock (I love living in no where and back country roads).

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1 hour ago, William1 said:

I've never had a problem with the air/oil separator/return tank. Sure, I'd like to have it not be there but it is not a real issue when working on the bike, it does its' job well. No one I have known has had 'no problems' once removed. They smoked on wheelies and consumed a lot of oil. After a 100 mile ride, they'd have to add half a quart. I consume about 10 ml in 1,000 miles, easily 100 of them at 12 O'Clock (I love living in no where and back country roads).

So you burn more oil, or lose it in the airboot when 12ing?

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8 hours ago, HansLanda said:

So you burn more oil, or lose it in the airboot when 12ing?

The separator has the surface area to catch oil droplets and condense mist, a simple "T" does not. Inside the separator is a open cell foam and baffles, all of which make it very difficult for oil liquid to make it to the airboot. Once the oil makes it to the airboot, it is ingested by the engine and burned/disposed of.

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3 hours ago, William1 said:

The separator has the surface area to catch oil droplets and condense mist, a simple "T" does not. Inside the separator is a open cell foam and baffles, all of which make it very difficult for oil liquid to make it to the airboot. Once the oil makes it to the airboot, it is ingested by the engine and burned/disposed of.

I know how it works, I was just asking about how the wheelies affect it.

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Just now, HansLanda said:

I know how it works, I was just asking about how the wheelies affect it.

Sorry, I thought that was what my explanation did. In the separator, there is not a direct path to open air, so if you are "up', oil droplets still have a near impossible route to escape. With a 'T', it can be a straight shot.

Nearly every part on a bike is needed, very few can be deleted. If they could be deleted, the manufacturer would of done so and saved a dollar.

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1 hour ago, William1 said:

Sorry, I thought that was what my explanation did. In the separator, there is not a direct path to open air, so if you are "up', oil droplets still have a near impossible route to escape. With a 'T', it can be a straight shot.

Nearly every part on a bike is needed, very few can be deleted. If they could be deleted, the manufacturer would of done so and saved a dollar.

I guess I need a custom box with the air vent hose at 3 o'clock pointed to the head, so the oil can't climb up it in a wheelie. Definitely not going to remove it entirely, don't worry.

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1 minute ago, HansLanda said:

I guess I need a custom box with the air vent hose at 3 o'clock pointed to the head, so the oil can't climb up it in a wheelie. Definitely not going to remove it entirely, don't worry.

Stock box already does have the hose at the 3 O'Clock position, pointed at the head. About the only improvement that could be done would be to use a catch can on the vent to the air boot side and loop the vent hose from that up as high as you can and down to the air boot.

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1 minute ago, William1 said:

Stock box already does have the hose at the 3 O'Clock position, pointed at the head. About the only improvement that could be done would be to use a catch can on the vent to the air boot side and loop the vent hose from that up as high as you can and down to the air boot.

The oil return hose is in that position yes, but the air vent hose is at the top rear of the box, pointing to the airboot. Which becomes the lowest exit point during the wheelie, and the hose going back to the head is the highest point.

I don't want to hijack the thread, so here's mine about it if you care to read. I'm not really troubleshooting this much anymore, but with the stock box, oil can climb up the air vent hose all the way up the handlebar.

https://www.thumpertalk.com/forums/topic/1227140-wheelies-leaking-a-lot-of-oil-in-the-airbox/

 

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3 hours ago, HansLanda said:

The oil return hose is in that position yes, but the air vent hose is at the top rear of the box, pointing to the airboot. Which becomes the lowest exit point during the wheelie, and the hose going back to the head is the highest point.

I don't want to hijack the thread, so here's mine about it if you care to read. I'm not really troubleshooting this much anymore, but with the stock box, oil can climb up the air vent hose all the way up the handlebar.

https://www.thumpertalk.com/forums/topic/1227140-wheelies-leaking-a-lot-of-oil-in-the-airbox/

 

If it were me, I'd take a standard small auto catch can with the port on the bottom and a filter on top. I'd mount it vertical somewhere high on the front of the bike. If the oil gets up there it would have to fill up that catch can before it came out through the catch can vent filter.

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