72' CB350 Twin - Oil Pump question?

[Danish_Cafe]

Hi all,

I'm in the process of putting my engine back together after a complete tore down.

My camshaft, rocker arms, and the housings for the cam where all in pretty bad shape, so i bought some new of ebay,
but i don't wanna put the old oil pump back in if that's what caused them to wear down.

I need a tip on how to check the oil pump, i can't seem to blow air through the outlet valve. Is this because it needs high pressure to open?

Any tips / ideas would be much appriciated?

Thanks, and hope my english is understandable :-\

 

[Big R]

I don't have an answer (sorry) but I am curious to see how this turns out. Maybe try to look through some of the cb350 builds and find an answer?

Oh yeah, and welcome to the site!

 

[DrJ]

The ball valve in the pump should move freely. If it doesn't, I'd replace it. Also the later 350s have the larger volume aluminum pump, that is the better one.

 

[Danish_Cafe]

i know the valve should move freely. But i mean, a far as i can sei it's only a valve consisting of a spring and a steel ball. I tried blowing pressurised air through it, but that didnt work, so i guess something is really wrong, and i might be better off ordering a new pump.

 

[Wee Todd]

Doctor J is right late pumps are better. The pump has an design fault..at high rpm the ball and spring start to float and oil pressure is reduced. Check to see that the cam and push rod attached to the clutch basket aren't worn out,,,my buddy melted down his motor at cayuga race track because of that,base gaskets can fail and starve the top end,,trust me I know :'(...if the check valve is moving and the oil pump piston and bore are ok.....it should be fine

 

[Danish_Cafe]

Thanks for the info guys. im not taking any chances, so i ordered a new pump today, found it cheap on ebay so better safe then sorry.

 

[Rocan]

1972 is already the later style pump.

you can check wear on the parts... the values are in the shop manual. find a replacement if its past a certain tolerance.


also its a good idea to blow compressed air through every oil hole.

 

[Danish_Cafe]

1972 is already the later style pump.

you can check wear on the parts... the values are in the shop manual. find a replacement if its past a certain tolerance.


also its a good idea to blow compressed air through every oil hole.

Hi Rocan, i already ordered a new pump, because i think the outlet valve has seized up or something,
all other oil holes has been cleaned and blown throught with air.

 

[Rocan]

Hi Rocan, i already ordered a new pump, because i think the outlet valve has seized up or something,
all other oil holes has been cleaned and blown throught with air.

did you get a new oil pump or an old one that is new to you?

if actually new, im curious where you got it from and for how much!

 

[Danish_Cafe]

It's a used one, from a bike with 8000 miles on it. So it's only new to me.
From pictures and description it looks as good as new, so i hope this solves the problem.