Norton Atlas Primary Chaincase without Footrest Support

I'm looking for advise on sealing my Atlas chain case (without stock foot rests). It's been a challenge keeping the oil inside so while I've got her apart for gearbox freshening, I thought I'd tidy-up the chain case sealing. This Atlas has rearsets and I installed a stock chain case. When I bought the bike it was a rolling basketcase with an open fiberglass chain guard. I obtained a stock chain case and fitted it without the foot rest support that normally bolts to the engine plates. Instead I used a piece of threaded rod, various nuts, washers and rubber washers in place of the foot rest support. On the back side of the case I've got a large diameter steel washer with a matching rubber washer to support the case and provide a way to seal the large hole in the rear case. In front I use another large washer and dome nut to hold the front case in position.
I'm not sure how the original foot rest support worked but I'm hoping someone might tell me if I'm in the right ballpark. I think my setup could allow the front case to be over tightened. Also wondering If I need to add any other sealing in the foot reset tube, etc.

And FWIW, I'm not interested in belt-drives, Commando chain cases, etc at this time.

Yes, you are in the ballpark, and yes the set-up could allow the outer case to be over tightened, as does the stock set-up.

Here is my solution to sealing the primary tinware on the Atlas. Note: some of the things I have done may not have been necessary, that is, I simply do not know whether the particular mod contributed to sealing.

1) I use a new big rubber gasket. I bond the rubber to the inner case with an oil proof adhesive, or in lieu, RTV. I attach the outer cover to apply a clamp pressure to the rubber until the bond is set.

2) Apply a generous bead of RTV to the edge (the 3/8 inch thick way) of the big rubber.

3) Apply a generous bead of RTV to the shoulder of the outer case ... this is the surface that will mate with the 3/8 inch edge of the rubber. The object is to have the beads merge when the outer cover is placed.

4) Smear a film of RTV around the wide flange of the outer cover on the bottom and half way up each end.

5) Fit the outer cover, tapping all around with a rubber mallet. With the stock foot rest set up, the large nut should be tightened until one or two threads is exposed.

The above is IMO necessary.

For insurance, I made the following mods (these are what may do nothing):

a) I fitted a 1/2 inch thick closed cell foam "donut" to where the cup on the outer cover mates with the tube on the inner cover. The object is to squeeze the foam when the outer and inner come together.

b) I split the sliding circular plate that fits on the inner cover and allows the mainshaft of the gearbox to move fore and aft for chain adjustment. I did this by drilling out the spot welds. Then I placed a large "O" ring inside the plates, and reassembled them with 4-40 screws and nuts with red LockTite, adjusting to have a snug, sliding fit.

c) I placed a gutter over the top of the sliding plate so as to channel oil to either side of the plate.

Do not overfill the chaincase .... about 7 ounces (my preference Ford Type F ATF) is sufficient. Fill and slowly kick over the engine, feeling the chain thru the inspection hole. When your finger detects oil on the upper chain run, that is enough.

Prior to doing steps 1), 2) and 3), I would get about a 1 inch spot of oil per week. Since doing the bead on edge, I have had zero spotting over months. But I must confess the bike has been out of service ... who knows what will result when I crank it up (next few weeks I hope).

If someone can chime in and give you a measurement of the length of the stock footrest spacer, you can then estimate how much your setup should be tightened. As I said above, one or two threads exposed on the big nut is sufficient, but no one in his right mind would ever think it would be so.

It is difficult to estimate the length of the stock footrest spacer when installed, but FWIW, my eyeballs say 4 to 4 1/8 inches.

Slick

The parts book lists a chaincase footrest tube felt washer - to seal it and prevent oil getting out.
In theory not a lot of oil gets thrown at the footrest tube, and its shape guides oil away.
But you may or may not find the felt lets oil out anyway....
A bit of silicone may make it more oil tight, or use something like a neoprene/ artifical rubber equivalent of the felt seal.

An important part of the chaincase design is the spacer thingy between the engine plates and the back of the chaincase,
to keep it the right distance away, and not get distorted.
We notice you have a nut on a threaded rod.
But unless that nut is locked there somehow, it is sure to move, and cause problems ?

An important part of the chaincase design is the spacer thingy between the engine plates and the back of the chaincase,
to keep it the right distance away, and not get distorted.
We notice you have a nut on a threaded rod.
But unless that nut is locked there somehow, it is sure to move, and cause problems ?[/quote]


The only way to lock that nut is to use 2 nuts and lock them both together, but only after you get the distant right first, once the 2 nut are locked together they won't move, other than that you seem to be on the right track, on my Manxman build I am going open belt drive with Commando clutch and no chain case at all.

Ashley

ashman said:

An important part of the chaincase design is the spacer thingy between the engine plates and the back of the chaincase,
to keep it the right distance away, and not get distorted.
We notice you have a nut on a threaded rod.
But unless that nut is locked there somehow, it is sure to move, and cause problems ?

Click to expand...

Ashley[/quote]

Yes, I thought of that. I dribble some blue Loctite on the threads before snug it up to the rear of the chain case.
I suppose I could double-nut it or use a lock nut but the Locktite seems to work and it allow me to spin the nut easier, since it's in an awkward location.

I was wondering about filling the space inside the tube with some closed cell foam. I did see some sort of felt filler online too.
I was thinking about a big rubber stopper with a hole drilled through for the rod.

I'm confused by the gap between the front of the tube and the front case. I would have thought the 2 would touch gently but they seem miles apart.

Slick, I was going to try the grease method of sealing the front case first because I've done the RTV method and it makes it such a pain in the ass
to remove the front cover. I suppose this all depends on the condition of the front cover. The one I'm currently going to try seems in good nick and
straight as they come. My previous cover was powder coated silver and I'm wondering if the coating was so thick it may have changed the dimensions of the sealing surface.

Thanks,
Mark

mschmitz57 said:

Yes, I thought of that. I dribble some blue Loctite on the threads before snug it up to the rear of the chain case.
I suppose I could double-nut it or use a lock nut but the Locktite seems to work and it allow me to spin the nut easier, since it's in an awkward location.

I was wondering about filling the space inside the tube with some closed cell foam. I did see some sort of felt filler online too. Agree ... this is an option to my "donut"
I was thinking about a big rubber stopper with a hole drilled through for the rod.

I'm confused by the gap between the front of the tube and the front case. I would have thought the 2 would touch gently but they seem miles apart. Agree ... this is where I put the donut. Nothing says you can't put the closed cell foam here and inside the tube. But I tend to agree with Rohan, it should not be necessary to fill these spaces, but I did it for insurance and some modicum of peace of mind.

Slick, I was going to try the grease method of sealing the front case first because I've done the RTV method and it makes it such a pain in the ass
to remove the front cover. I suppose this all depends on the condition of the front cover. The one I'm currently going to try seems in good nick and
straight as they come. My previous cover was powder coated silver and I'm wondering if the coating was so thick it may have changed the dimensions of the sealing surface. I do not find the cover to be overly hard to remove .... the RTV simply does not "stick" that well to the rubber. I went the grease route first .... never totally eliminated spotting for me. I have to admit, the first time I used RTV, I was apprehensive about removing the cover .... I was surprised how easy it did come off.

Thanks,
Mark

Click to expand...

Slick

If you use 2 nuts locked together and tighten up they won't loosen up at all so you won't need use any loctight at all I have been using this meffort for many years and have never had two nut locked together come loose yet, but you got to lock then together pretty tight to make it work.

Ashley

@mschmitz57
Mark, the stator is the wrong way round mounted:
Note that the stator should be fitted with the lead taken offside towards the outer primary chaincase and not towards the inner portion of the chaincase.
I've found this in one of my «Heavy Weight» manuals. I'm sorry, couldn't find the manual with this statement anymore :cry:

Fritz

bad_friday said:

@mschmitz57
Mark, the stator is the wrong way round mounted:
Note that the stator should be fitted with the lead taken offside towards the outer primary chaincase and not towards the inner portion of the chaincase.
I've found this in one of my «Heavy Weight» manuals. I'm sorry, couldn't find the manual with this statement anymore :cry:

Fritz

Click to expand...

My Norton manual so states as the green text above, but I have found it works either way 'round. I think the wires outside is preferable to keep them away from the chain. My philosophy is ... do it (whatever) the manual way whenever one can, unless one can strongly justify otherwise.

Slick

I'll give it a try, but I think having the rear-exit cable puts it more in the path of the chain.
On Commando's the cable exits forward on the stator so it made sense to me to duplicate the positioning.
Also the cable is quite safe routed through the bracket on the primary case. It just makes more sense to me.
I'll be danged if I can find any pictures on the web showing the rear-exit arrangement.