Very oily diaphragm/valve

[MasterGuns]

Was installing new diaphragms/sliders tonight. When I pulled #2, there was so much oil inside the cover that it even dripped out when I removed the final allen head. That was the only one like that. What in the world could cause excessive oil build up in the diaphragm. There is a minimal amount of oil that had accumulated in the airbox being brought up through the crankcase vent but nothing alarming. Even if oil we to accumulate in excess in the airbox, I doubt it could find its way to the diaphragm. It was running fairly well before and since I have had four new sliders/diaphragms I figured I go ahead and get them installed. Any ideas about the oil? Thanks all!

[Marcarl]

I too would be interested where that would proceed from.

[GeorgeS]

Must likley the crankcase Vent. But usually builds up on all 4 carbs. Hmmm ??? just one, thats interesting.

 

I Installed the bypass hose, my carbs stay clean noww. And the clamps for the airbox, and mount to manifolds, stay in place real good now also.

[MasterGuns]

Must likley the crankcase Vent. But usually builds up on all 4 carbs. Hmmm ??? just one, thats interesting.

 

I Installed the bypass hose, my carbs stay clean noww. And the clamps for the airbox, and mount to manifolds, stay in place real good now also.

 

George, Thanks for the reply but you've got me wondering exactly what you've done to correct oil being sucked up into the airbox. Not sure that is my problem but most likely it is. If you wouldn't mind please PM me with the specifics on what you did. Appears I must do the same.

 

Thanks

[Condor]

George, Thanks for the reply but you've got me wondering exactly what you've done to correct oil being sucked up into the airbox. Not sure that is my problem but most likely it is. If you wouldn't mind please PM me with the specifics on what you did. Appears I must do the same.

 

Thanks

 

Herb, I think Earl/Skydoc 17 put together a kit to eliminate the crank hose. I tried to find it in the classy's but couldn't. That may be what George is refering to??

[rhncue]

I have a question. If the hose going to the air box causes so much of an oil mess in the box and running down the carbs, how does that crankcase filter alleviate the mess? It seems that the blow-by would just be worse as none would be getting burned in the carbs. I just remember the mess that occurred on engines back when Detroit used crankcase vents before the advent of PCV valves. Inquiring minds want to know.

 

Dick

[Snaggletooth]

The breather hose runs from a vent tube on the top of the crankcase to the bottom of the air box. The crankcase is zero pressure but the intake in the air box creates a vacumn that pulls vapor from the crankcase up into the air box and back into the intake to the carbs. The problem of oil getting into the air box is most noticed when the engine is over filled with oil, past the half way mark on the sight glass, and oil ends up in the box. Therefore the reason for the drain tube on the front left corner of the box. There is a mod for that that returns the oil back to the breather tube for another go around.

 

The filter they are talking about is installed on the vent tube on the top of the engine, therefore eliminating the breather tube back to the box itself. So no more oil is passed that way, so no build up in the box. The port on the bottom of the box is simply plugged off.

 

As the crank case is zero pressure the filter is nothing more than a vent, but filtered. As long as you don't overfill the oil it is a good fix. No more fighting to put the hose back on.

[MasterGuns]

I read a couple replies on this thread stating that oil in the air box is related to too much oil in the crankcase. So, I am really curious about how much oil should be added to an entirely drained crankcase. I have always drained the oil by removing the drain plug, removing the bottom most allen on the middle gear cover and allowing each to drain until it stops dripping. I also allow what oil will drain when the filter is removed. At times I have let it sit there for thirty minutes or so with both plugs and the filter removed. Then I install all the plugs and a new oil filter and add FOUR quarts. Is FOUR quarts too much? I have been adding four quarts to these 1st editions since 1986 and can't believe I have been adding too much oil for 23 years. Please tell me this isn't so.

[Dano]

Book calls for 3.4 quarts without filter change, 3.7 with filter change. I'd say that's why you gots yurself a reallllly big mess there, gunny! Only fill to halfway up the glass. I put 3 quarts in mine, then start it up and let it run for a minute to charge up the filter and oil passages. Then shut 'er down, wait a minute and top it off to the halfway mark. This should help you out with the oil well!

 

Dan

[MasterGuns]

Dan, I guess that once the air box fills with .3 quarts of oil, I won't have to drain any off. I am going to put this thing on the center stand asap and using a syringe, suck oil from the crank case until the level drops to center of the sight glass. Been adding four quarts for decades and to many different 1st editions, and never had this problem. We'll see. Thanks so much

[Dano]

Just for s**ts and giggles, have you done any mods that might increase airflow? K&N filter, needle mods or such? If this is the first time you've had a problem with this, think back to when it started and see if you did something different.

 

Another thought, you might do a compression test with a leak-down test thrown in. If the rings are not sealing properly, it could be creating pressure in the crankcase, therefore helping "push" the oil up into the tube.

 

Just some random thoughts from an otherwise previously engaged brain.

 

Dan

[skydoc_17]

During the early 70's The newly formed EPA said that no vehicle can be sold in the US that vents combustion byproducts into the atmosphere. All the auto and motorcycle manufacturers were scrambling to create a "stop gap" measure to divert the old "road draft tubes" to a place that would allow the vehicles to be sold in the US. It turned out the the PVC system was such a cheap fix the to this day it is used and causes many of the problems I fix on motorcycles and other vehicles every day. Introducing oil into the air intake system of a bike or car is not a good thing from a performance standpoint and if adversely affects all parts of that system. It decreases gas mileage, fouls plugs, contaminates carbs and fuel injectors, and ruins air filters, or in the case of the K&N filter causes you to clean and recharge them a lot more frequently.

I recently pulled my ad for the Crankcase Vent Filter Mod because of complaints from the "tree huggers", but after consulting some of the other members I have decided to put the ad back in the classifieds and let each rider decide for themselves if this is a mod that you want to do to your bike or not.

My name is Earl Harrell and I welcome your comments.