48 oil pump

Lubrication System (oil feed pump and scavenger pump, reservoir, filter, and lines)
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1951 adam
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48 oil pump

#1

Post by 1951 adam »

I started to mock this up tonite, installed new studs...all threads look good, however the inner screw with the flathead that sits into the body, does not bottom out on body. I checked the threads in the case and they look OK. This is the colony pump mount kit complete, I'm wondering if its not an exact reproduction of the original screw. I will try and run a 1/4 24 into the case tomorrow....could be because the case is an early 51, it had the late style pump cover with a stud. I only need 1 or 2 threads to bottom it on pump body. This bike had an S&S pump on it since I got it. My one and only paper pump to case gasket ripped at the stud when I was installing it..DAMN. I did mock it up with gears and keys to make sure she turned freely, slight drag but not bad..turned pinion pump gear with my finger. I did notice that you have to draw the pump in evenly and I star patterned the bottom nuts, and then the top nuts. I installed the pinion gear , and turned the sprocket shaft on the bench, seems OK....anyone know, how much drag or bind is normal, 2nd thing, Im using the small key on the return gears, when did they go to the -15 keys on all the key ways? any pointers would be much apreciated, Adam
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Re: 48 oil pump

#2

Post by RUBONE »

Adam,
Small key is right. The longer key is for alloy bodied pumps. The cheese head screw should go all the way in, if not there is likely some sort of junk in the hole. I can measure an original if you like in the morning. It isn't because of the year of the case. The screw fits both Knuckles and Pans .
Robbie
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Re: 48 oil pump

#3

Post by 1950Panhead »

Turning the pump shaft with the pump assembled you can feel the gears turning, if there is any binding something is wrong.
I think the case threads (for the pump) are 1/4-20, clean the threads with a qtip, use a new bolt.
When certain you can clean case threads with a tap, just don't make a mistake.
The gear cover screwsa are 1/4-24, but I think the pump is 1/4-20, be careful.
Jerry
1951 adam
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Re: 48 oil pump

#4

Post by 1951 adam »

I did tap the case tonite, for the cheese head screw, and your right Robbie I did just have to run the tap in to clean it up. Jerry, the pump studs are 1/4 24, and the cover to body is a 1/4 20, I think it depends on the sequence that you tighten the pump nuts down, as far as binding, I can turn it free , and I have really just a little drag...I think It feels OK, I'm confident shes good. I still need to pull it apart one last time to replace the body to case gasket, It was so old, it ripped as I was getting it over the studs....uploading some shots
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