A: Oil Pipework Series D oil tank

davidd

Well Known and Active Forum User
VOC Member
Greg is correct that the C chain oiler is a moonlighting as a breather, but not by logic. It is because there is another hole in the block that is not visible, but shown in the riders handbook!

I'm thinking of getting another D-style ET24/6 and after modifying the return block, piping the disabled chain oiler to that. I say "another" because I already have one over the inlet valve on the front cylinder, connected to a hose with a one-way valve and an extension out the back past the rear axle.

Gary,

I am not sure I understand why you want to add another breather, but I know multiple breathers are popular. I have never had any problems with any breather on a Vincent including the caps. You do have to check the holes in the caps to make sure they are not plugged up.

Unlike the C, the D has a number 70 Amal jet in the chain oiler, but also uses the standard metering screw used on the C, which is probably Amal also. The taper on the metering screw is almost always damaged, which is only important if you intend to use the oiler sometime.

I know of D oil tanks where the filler neck has cracked along its mating line to the tank. You can zip tie a rag on it and figure out if the leak is coming from the tank joint or the cap.

David
 

Bill Thomas

Well Known and Active Forum User
VOC Member
I wonder if Gary is useing a very thin oil, Which might make it worse, I know some people think that is the way to go, But not me.
With the breathers, You get better air flow if you fit the "D" cap over an adjuster rather than the valve.
Cheers Bill.
 

BigEd

Well Known and Active Forum User
VOC Member
VOC Forum Moderator
I wonder if Gary is useing a very thin oil, Which might make it worse, I know some people think that is the way to go, But not me.
With the breathers, You get better air flow if you fit the "D" cap over an adjuster rather than the valve.
Cheers Bill.
Didn't the "D" heads have clearance up through the front exhast valve area to allow breathing up there? I think I did a bit of fettling on my "B" front head to try out a "D" cap. I've got the heads off at the moment so I'll have a look when I check the valves etc.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Didn't the "D" heads have clearance up through the front exhast valve area to allow breathing up there? I think I did a bit of fettling on my "B" front head to try out a "D" cap. I've got the heads off at the moment so I'll have a look when I check the valves etc.
Yes, But I don't think as good as above the adjuster. Cheers Bill.
 

greg brillus

Well Known and Active Forum User
VOC Member
Grind a small flat on the side of the upper guides and align it with the circular cut away above the rocker. That gives plenty of air space. Quickest way to destroy the looks of your engine is cover it in unnecessary breathers. Motorcycle manufacturers back then were very slow to realize the importance of the placement and size of engine breathers.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
I was too young !!, To know Jim Smith, So I got Brother Ron to alloy weld a curved bit of alloy Bicycle handle bar to the A.T.D. cover, Didn't want to Begger up the T/case, On one of my bikes', Agree with Greg, It did look rubbish, But Needs must.
Now the bike and me are "Out to grass ", Last year I put " Our John's" Breather Cap with a valve, On the front inlet adjuster position, Looks very neat, I think, No good to Gary, John is in U.K. Cheers Bill.
 

Gary Gittleson

Well Known and Active Forum User
VOC Member
I'm going to try to answer the questions raised.
1) I am using 20w50 Valvoline oil
2) I thought of piping the chain oiler to a T fitting at the existing breather but that might pump more oil into the one-way valve that it would like. I don't like lots of breathers around either but I the caps over the valves are pretty hidden under the tank and the hoses are pretty well hidden too.
3) I checked the tank for leaks with petrol. No problem there. I did try a bit of that leak-finding dye. After a 100 mile ride, it shows up all over the rear of the tank, down onto the RFM etc.

So what of that article I mentioned? I don't quite see why one would need to plug the adjuster hole down below, instead of just screwing the thing all the way down.
I can actually see the second hole in the block.

I like the look of David's "carb slide" device.
 
Last edited:

davidd

Well Known and Active Forum User
VOC Member
Gary,

When I noticed yesterday that no one had answered your question I did not think it would generate this kind of interest!

It seems to me the the oil is fine.

In general, the D breathers were a compromise due to cost. They seem to work fine if the engine is tight. I like the timed breather or a reed valve on my own bikes. The D breathers had modified top valve guides so they would pass air and oil more easily. That is a bit of work to do. Most owners want the on the rockers because that is the best way to get rid of the oil and air. Oil laying around the valves can often find its way down the guides.

I would not have thought that the D oil tank could become pressurized enough to leak through the vent hole of the cap unless something odd was happening. I know the scavenge side of the pump works twice as hard, but it only pumps what is there in the chamber. I would have thought that it would not be willing to pass air unless your crank cases were unduly pressurized. If your oil tank is unduly pressurized, I would hate to pass that back to the engine via the mod.

Based on the assumption that most things are OK in the engine, I assumed the oil weeping was from the splashing in the tank filler.

A view of the chain oiler is shown on page 19 of the Rider's Handbook. If you screw the taper into the tiny hole you can see, air and a very small amount of oil can still enter the chain oiler tube from the large hole on the right side of the block That creates a drain for what I assume is any excess oil from that tiny chain oiler hole that the metering screw works on. The only 100% way to block off the chain oil tube is to plug the end coming out of the tank.

It might be worth trying an aluminum disc under the screw to determine whether your problem is just splashing or something more serious like splashing plus pressurization from the engine. You might also run a little less oil in the tank as a test to see if increasing the air volume gives you any benefit, like allowing the splashing to subside a bit.

David
 
Top