Misc: Oil Oil Capacity

[Gary Gittleson]

I've been wondering for some time what the recommended oil capacity is for a Series D. Mine is an open D although I don't think that makes a difference.

I have heard such figures as 2 1/2 US quarts. I took the tank off and tested that theory. No way. That puts the level just under the filler cap.

 

[Robert Watson]

Did you change the filter as well??

 

[Gary Gittleson]

I change the filter every second time. So I suppose I would need two capacities; one with and one without changing the filter. I just finished draining the oil (crankcase and oil tank) but it's not time to change the filter. There's no hurry to put new oil in. It's still bloody cold around here.

One thing I've learned is that overfilling the tank will cause oil to get around the cork on the cap and splash out. I've done all sorts of things to stop that and it's better, but still does it to some extent. I made a deflector for the return, bought a ventless cap (oil was coming out the vent hole) and diverted the chain oiler to a modified valve cap as a breather just for the tank. All of this helped but still, the top of the tank will be wet with oil if the level is high enough to be visible from the filler. It has to be lower and I have to use a stick (a spoke, actually) to check the level.

 

[BigEd]

I change the filter every second time. So I suppose I would need two capacities; one with and one without changing the filter. I just finished draining the oil (crankcase and oil tank) but it's not time to change the filter. There's no hurry to put new oil in. It's still bloody cold around here.

One thing I've learned is that overfilling the tank will cause oil to get around the cork on the cap and splash out. I've done all sorts of things to stop that and it's better, but still does it to some extent. I made a deflector for the return, bought a ventless cap (oil was coming out the vent hole) and diverted the chain oiler to a modified valve cap as a breather just for the tank. All of this helped but still, the top of the tank will be wet with oil if the level is high enough to be visible from the filler. It has to be lower and I have to use a stick (a spoke, actually) to check the level.

Do you check the level cold or after running the engine? There may be oil in the sump that pumps up after startup that raises the level in the tank.
Many owners of non 'D' machines have topped up the UFM tank and had the oil from the sump run over the top of the engine. (Before you ask the question; yes I have a couple of times.

 

[Marcus Bowden]

Are you sure it's not a double start pump in the engine as that will splash oil about the filler cap, as I've had a double start fitted since 1990 when I fitted the Honda pump to supply the cams and they have survived two more lots of 100k miles since I fitted them in 1970, having 1 bar (15psi) squirting up under the cam followers certainly makes a difference .
bananaman.

 

[Peter Holmes]

I change the filter every second time. So I suppose I would need two capacities; one with and one without changing the filter. I just finished draining the oil (crankcase and oil tank) but it's not time to change the filter. There's no hurry to put new oil in. It's still bloody cold around here.

One thing I've learned is that overfilling the tank will cause oil to get around the cork on the cap and splash out. I've done all sorts of things to stop that and it's better, but still does it to some extent. I made a deflector for the return, bought a ventless cap (oil was coming out the vent hole) and diverted the chain oiler to a modified valve cap as a breather just for the tank. All of this helped but still, the top of the tank will be wet with oil if the level is high enough to be visible from the filler. It has to be lower and I have to use a stick (a spoke, actually) to check the level.

The oil leakage from the oil filler cap on my D Comet drove me crazy, I tried all the things you have tried, and nothing was 100% successful, at its worst it was bloody dangerous, covering the RHS of the rear tyre liberally with oil, the problem always manifested itself at its worst if I had been engaged in what we might describe as spirited riding, lots of revs, in the end I have managed to cure it once and for all, I did have to sacrifice a FT130 to achieve the remedy, I don't own a lathe, but managed without one, hacksaw the threaded projection off the FT130 to leave you a thick flat disc, reduce the diameter of the disc to exactly fit inside neck of the oil tank, drill a hole through the disc to correspond with the chain oiler adjuster screw, countersink a little the threaded centre just to clear the filler cap, although that might not be necessary as it will sit quite low in the oil tank neck, then to the side drill and tap a 4mm thread, this is to enable removal of the disc when required, I leave a 4mm x 20mm socket cap head screw loose on top of the disc, always there when needed, and it can't go anywhere.

A very low tech, Heath Robinson solution, but it has completely solved the problem for me, I can now rev the nuts off it, especially when chasing my Son on his NSR 250 (no chance whatsoever) but when I check the top of the oil tank it is as dry as a bone, and removal for checking oil level and topping up is achieved in a thrice, and without the need for any tools.

 

[bmetcalf]

Can you post a photo?

 

[Peter Holmes]

If I had a lathe and other tools I could do a lot better job, but this has solved my problem completely.

 

[Gary Gittleson]

Do you check the level cold or after running the engine?

Yes. I check just after running.

Are you sure it's not a double start pump

Pretty sure. I never took the pump out (leaving well enough alone) but I've had the bike since 1976 and sort of doubt such a modification was done before that.

The deflector I made doesn't close off the top to the extent that Peter's does. I might try that. I can make one of those on my little Atlas lathe.

So that leaves the original question. What's the normal amount of oil for the D? If Peter's solution works that well, I suppose I could make such a disk and then just fill to a bit below the top of the chain-oiler block and find out that way.

 

[Peter Holmes]

I was just using what I had lying around, if I had a lathe at my disposal I would not have a central hole where the threaded part of the FT130 was, but just a small blind countersink, and I would do a more accurate job of sizing and placing the hole that drops over the chain oiler adjuster screw, one thing that might be difficult to see in the photo is I put a decent size copper washer under the head of the adjuster screw, and that is held in situ by the spring, I have the adjuster screw turned down tight-ish, and by some stroke of luck the chain seems to get just enough oil to stay lightly lubricated, but not overly, and splashing everywhere. My disc sits on the washer and is a very snug fit into the filler neck of the tank. I had previously made what I thought was a beautifully crafted deflector plate, which would have made it possible to visibly check the oil level and top up if necessary, but much to my surprise it did not solve the problem, the problem can only be caused by splashing caused by the force of oil returning to the tank, it can’t capillary itself up to the filler cap seal, and it can’t splash past the disc, somehow it did past the deflector.

In my case running the oil level lower did not eradicate the problem, now I run the oil level just below the filler neck, I think any higher and you probably do risk simply overflowing, my disc will not stop that.