AMR oil pump/checkball mod, re wet sumping

mightydaj · Dec 1, 2014

I had the AMR mod done to my 74 850. It went from wet sumping in 2-3 days to 3-4 weeks. Did not totally stop it, but is now long enough that it is not a concern since I ride it at least every few weeks. I am very happy with the AMR service.

JimC · Dec 2, 2014

mightydaj said:
I had the AMR mod done to my 74 850. It went from wet sumping in 2-3 days to 3-4 weeks. Did not totally stop it, but is now long enough that it is not a concern since I ride it at least every few weeks. I am very happy with the AMR service.

Did you have the AMR oil pump mod, as well as the output spring and ball?

mightydaj · Dec 2, 2014

Yes, I had them both done. I could feel the difference in the oil pump by turning it, much "tighter" after the fix.

htown16 · Dec 3, 2014

The timing cover and pump are off the bike and packed for shipment tomorrow. I will follow up results when it's back on. I'd be happy if it just slowed the wet sumping down. I do ride the bike every 1-2 weeks. Also, I'm not afraid of starting it with the oil level in the tank down some. That's never hurt it before. I just can't bring myself to start it when the intake screen is showing.

gjr · Dec 3, 2014

I had this modification done (20+ years ?!) a long time ago and it works fine. Even after standing all winter the crankcase does not need to be drained before starting the bike. O-rings on the pump shaft were not an option then. I did lap the pump cover.

Greg

rgrigutis · Dec 3, 2014

Had amr do both my combat and mk2a and they don't sump at all. Mind you they never sit for more than 6 weeks at the most. Amr rebuilt my amal 932's with their slides and they run great, rock solid idle, and they they start the bike in a nanosecond with the alton e start. They're a solid operation

MikeM · Dec 3, 2014

As the tank drains to the sump, is there any problems leaving the oil in the sump til spring and then draining it?
Will it seep into the primary or go somewhere it shouldnt?
I dont plan to drain the sump until I am ready to ride in the spring.
MikeM

texasSlick · Dec 3, 2014

MikeM said:
As the tank drains to the sump, is there any problems leaving the oil in the sump til spring and then draining it?
Will it seep into the primary or go somewhere it shouldnt?
I dont plan to drain the sump until I am ready to ride in the spring.
MikeM

It can weep into the primary via the three screws that mount the inner primary cover to the engine.

Slick

Hobot · Dec 3, 2014

Not considered concurs museum ideaism for a rare exotic priceless Commando but its world wide decades long routine w/o any issue if not using oil that still needs a can opener to serve. In rare cases combustion moisture acids could injure surfaces but oil that used up bad has already done as much or more surface injury. By and large its long term full wet sump that perseved many Commando found and made road worthy with all the major items just fine. I'm sure some will request proof so better report back on heated oil flush then fresh storing oil in correct grade for the climate.

MikeM · Dec 4, 2014

texasSlick said:
MikeM said:

As the tank drains to the sump, is there any problems leaving the oil in the sump til spring and then draining it?
Will it seep into the primary or go somewhere it shouldnt?
I dont plan to drain the sump until I am ready to ride in the spring.
MikeM

Click to expand...

It can weep into the primary via the three screws that mount the inner primary cover to the engine.

Slick

So it would be a good idea to drain the sump over the winter? Pour it back in and drain it again? I thought my HD was labor intensive.

texasSlick · Dec 4, 2014

MikeM wrote"

So it would be a good idea to drain the sump over the winter? Pour it back in and drain it again? I thought my HD was labor intensive.

The sump can hold some oil before it seeps into the primary (maybe a quart?).
Why not drain most of the oil from the oil tank, when you put it up for the winter, and let the remainder wet sump? Then, pour the drained oil into the tank prior to the first start. If you forget to refill the oil tank, there will be oil in the sump to prevent disaster. You could put a NO OIL flag on the ignition switch as part of your winterizing routine.

Slick

MikeM · Dec 5, 2014

texasSlick said:
MikeM wrote"

So it would be a good idea to drain the sump over the winter? Pour it back in and drain it again? I thought my HD was labor intensive.

The sump can hold some oil before it seeps into the primary (maybe a quart?).
Why not drain most of the oil from the oil tank, when you put it up for the winter, and let the remainder wet sump? Then, pour the drained oil into the tank prior to the first start. If you forget to refill the oil tank, there will be oil in the sump to prevent disaster. You could put a NO OIL flag on the ignition switch as part of your winterizing routine.

Slick

Next year that will happen. Force of habit to change the oil before winter and I just filled the tank. My HD wet sumps as well and it seems to be normal.
Start it in the spring and dont rev it till everything is back where it should be with no problems. Seems to be the HD way.
This Norton is a completely different animal.

Deets55 · Dec 6, 2014

Mike,
How about sliding the hoses off their engine fittings and plugging them w/ a bolt and clamp. That will keep the oil in the tank and dangling hoses near kick starter will remind you not to start the bike.

Pete

Hobot · Dec 7, 2014

Ugh Unless the oil already past need of change it'd be undetectable difference to just let it wet sump and change when really needed. You won't get an A+ in museum or concors classes of course so don't tell anyone if ya do or don't. Do note going by the best non brainer wisdoms still leaves old oil in TS case and crank shaft so don't skip those damage prone zones of cam drive and big end decay before a season or so hibernation.

AMR oil pump/checkball mod, re wet sumping

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