Shelby-Right
VIP MEMBER
Yep , I think it is really good , haven't left it long enough though , I keep riding , it's tough , I ride all three , , it helps keep the battery's up ! , , I need to mark the dip stick and leave it for a week .
Obviously it was sumping bad prior ?Yep , I think it is really good , haven't left it long enough though , I keep riding , it's tough , I ride all three , , it helps keep the battery's up ! , , I need to mark the dip stick and leave it for a week .
To me wet sumping is all about the operation/tolerances of the pump...the cover alone is lipstick ...which is why AMR do the pump and cover modifications in unisonI think in about 5 days it was right down , but still over the screen , this may have increased as I noticed the heavy oil filled crank , made it a lot harder to start, I purposely left the pump , as I want to try the cover , i:e just one change . It's easy to get the cover off if I need to service the pump . Cheers.
Each to their own i suppose... I only engage that thought for carburetor tuning mainly...my service included new pump (fitted & tested).. seals....new timing chain ...new rotor and pick up plate (that i had on the shelf) and mk3 plunger cover..with a SRM oprv ...ive observed the norms and have had a op gauge fitted for quite some time...and from its readings was why I fully serviced the timing chest....I won't be digging back into that for a long time....meanwhile I will service/modify the original pump (fit seals) and bore mk2 cover to except spring and ball...for another rider or for myself at a much later date....CheersAll good , but for me , like fault finding at work, one change at a time makes it easier to pin point the problem .
Well, that ignores my firsthand experience (post #216 on this thread) plus the 3rd by AMR:I am amazed by the shear volume of threads/posts on Norton heavyweight twins oil pump/wet sumping!
Doesn't everyone understand by now that there is only one main reason for wet sumping - Excess end float of the pump gears allowing oil to leak between the end of the gear and the pump end plate. Any other reasons have nothing to do with the pump.
Doesn't everyone understand by now that there is only one main reason for wet sumping - Excess end float of the pump gears allowing oil to leak between the end of the gear and the pump end plate. Any other reasons have nothing to do with the pump.
Agreed LesHowever, maintaining a tight fit between the gears and end plates isn't practical unless the pump is lapped every few hundred miles or so.
The factory accepted that by (eventually) fitting the anti-drain plunger to the 850 Mk3 timing cover.
Also, regardless of the fit between the feed gears and end plate, there's still the potential for leakage 'across the pump' between the crests of the teeth and housing of both feed gears and perhaps to a lesser extent between the meshed gear teeth.
Checking the oil pump
Low oil pressure - indicated on the oil-pressure gauge or dashboard warning light - could provide an indication of wear or damage to the pump.www.howacarworks.com
Don't forget a damaged or not sealing oil pump discharge seal , or missing seal .However, maintaining a tight fit between the gears and end plates isn't practical unless the pump is lapped every few hundred miles or so.
The factory accepted that by (eventually) fitting the anti-drain plunger to the 850 Mk3 timing cover.
Also, regardless of the fit between the feed gears and end plate, there's still the potential for leakage 'across the pump' between the crests of the teeth and housing of both feed gears and perhaps to a lesser extent between the meshed gear teeth.
Checking the oil pump
Low oil pressure - indicated on the oil-pressure gauge or dashboard warning light - could provide an indication of wear or damage to the pump.www.howacarworks.com
With that seal missing, wet sump quickly gives way to crankcase air ventilation sumping, just ask SwooshDave...Don't forget a damaged or not sealing oil pump discharge seal , or missing seal .
Assuming your 73 is an 850 or a 750 with the big nut on the bottom of the engine...Most of the discussion here is essentially dancing around denials of the fundamentals. If oil is contained in a reservoir that's above the location of a gear-driven oil pump, given time (whether long or short periods) it will drain because GRAVITY ALWAYS WORKS. It isn't just Nortons either. Equally afflicted Harley-Davidson finally acknowledged the fact by moving the oil container to a level nearly even with the pump as a pseudo-sump on Big Twins. Buell did the same by using the swing arm on the XB models as the oil reservoir. Air-cooled Sportsters never got either solution and while not particularly prone...they do sump.
Accepting that, and adding the fact that I do not ride any of my ten machines as often as I should, particularly the 850 Commando, I am convinced that the reed-type, sump-located, breather is the best compromise overall. Not only for dealing with dumping effectively but for vastly improved crankcase breathing benefits.
Regarding their use on my 1973 model, I see choices and have questions. Whether JS Motorsport, NYC Norton, or the (apparently discontinued) CNW, there are slight variations in the same concept. I can sort that, but the one thing they have in common throws me. All of them have a "standpipe" which doesn't exist on the stock sump plug they replace. Not being an expert on Commando oiling, I can only guess it is there to ensure the reed will get airflow and not clog with oil in a sumped engine. This makes me curious about whether one of these would work without a standpipe. I also wonder if the NYC version, using a swivel banjo is more leak-prone in the long run. On the other hand, does the fixed outlet on the JS Motorsport version limit hose routing options?
Can someone explain (and help clarify) the design details on these reed sump breathers, please? These things are too much money to mistake.
No - we aren't talking about the same thing! I'm not asking about the nipple that the hose connects to, rather it's the tube that sticks up above the screen. Also, the current cNw breather is out of the question, but I was under the impression they used to have one similar to the NYC/JS type...sorry to confuse.Assuming your 73 is an 850 or a 750 with the big nut on the bottom of the engine...
The "standpipe" connects to the pipe in the neck of the oil tank via a hose. There is no way to eliminate it and you shouldn't want to. There are no issues with the "standpipe" for any of them on a 73 model. The cNw breather requires your crankcase to be sent to cNw empty. Unless your engine is apart, buy the NYC or JS Motorsport breather and follow the instructions - one of the best things you can do for a Norton.
The tube that sticks up above the screen into the crank case, is there to ensure the oil level is left in the crank case.No - we aren't talking about the same thing! I'm not asking about the nipple that the hose connects to, rather it's the tube that sticks up above the screen. Also, the current cNw breather is out of the question, but I was under the impression they used to have one similar to the NYC/JS type...sorry to confuse.
Well known fact and well discussed. The scavenge (oil return) side of the oil pump pumps more than the feed side. Clearly, the sump would be full while running if that were not the case! This is also a fact on every "dry sump" British bike I am aware of (probably every dry sump engine ever built).It seems to me too much oil in the crankcases would be nearly as bad as too little if it meant "sumping" while running was putting a lot of drag on the flywheels, extra pressure in the cases, and so on. In fact, this sort of implies that the stock oiling system/pump has a feed/return ratio that I've never heard/seen discussed. Is the pump geared to scavenge as much as it feeds...more...less?