Oli Pump stiff

S

stevepm2011

Hero member
Location
Cologne, Germany
Just thought to share this experience with you, might save someone some trouble & cash:

As I had removed the primary drive cover from my 1200 TS, I took the oil pump off to inspect it for damage.
The (9mm) pump was fine, so I propmptly put it back on - only to find it would no loger turn smoothly. It really had to be forced around.  :o
I pulled it off again, and checked for the obvious things such as foreign objects, gear protruding above the housing etc.
No improvement. FFFFF !!  :'(
And I really didn't want to replace what had up till now been a perfectly good 9mm pump.
After tearing what remains of my hair out, I put it under the magnifying glass - literally.
Looking at the slight but definite wear patter on the teeth, I realised that it was not symmetrical all the way around the two gears.
At least one of them was eccentric! 1980's Italian quality had struck again. :-X

But at least the fix was now obvious: find the position the gears had bedded in to.
Take one gear out, rotate a few teeth and try again. After a couple of attempts - Bingo!! The pump rotates freely again.

One happy lad, break out the cold beer!
Steve



 
It's great that you have got it going smoothly Steve, but that is pretty poor quality control by whoever made the pump.
There will of course be extra internal leakage across the gear teeth as the clearance opens and then closes to the pump body, due to eccentricity.
I expect there is enough oil to lubricate everything even with leakage, but in the long run I would be putting a new pump in - assuming of course they are not all like that?

Just my opinion for what it's worth.
 
I had this exact same issue with a brand new high output oil pump.
Seems at that time (around 2008) there was a bad batch going about.

The supplier changed the gears and all was well in the end.
You never know what is still going about so if you buy a new one it would be worth checking before bolting it all back up.
 
Grant,

I really like your "give a Fuck O-Meter"
But the needle movement seems a bit exaggerated - it actually twitches if you watch it for long enough!!
Agree with you, check everything by hand before  you consider putting it under load.

Simon,

You may be right about the leakage, although it ran happily for nearly 40,000km so I'm not going to lose any sleep over it.

Steve
 
Your oil pump isn't faulty, it's actually meant to be like that. It's not a gear pump. It works on the epitrochoidal displacement principle, somewhat like a Wankel engine except that it has two rotors instead of one. The gear teeth are only there to synchronise the epitrochoidal lobes on the rotors, so it's important to get the timing correct as you have discovered.

;)



 
Epitr.. what??

Considering the fun the Italians have traditionally had with conventional piston engines, it's probably just as well they didn't try to build Wankels :D
I'll bet Laverda invented the oval piston as well (accidentally)

Steve
 
stevepm2011 said:
Epitr.. what??

Considering the fun the Italians have traditionally had with conventional piston engines, it's probably just as well they didn't try to build Wankels :D
I'll bet Laverda invented the oval piston as well (accidentally)

Steve
Click to expand...
If your piston (skirt) isn?t oval (cam ground) you had better modify it before assembling. And don?t insult our Italian piston engines  >:D
 
    I had a Madras curry last night, so l'm just off for an epitrochoidal displacement....

                                                eric
 
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