VH OIL PUMP

[robin rose]

I am rebuilding an ex basket case VH and am investigating the oil pump back up valve which seems to locate within
the timing case on the crank centre between the quill delivery pipe and a retaining plug adjacent to the pump output.
I wish to remove and inspect/service the valve but am not sure which is the best way to remove the quill or plug as
I am not sure if they are threaded items or pressed so before I start leaning on them could someone give me a hint!
Also any tips on rebuilding the oil pump would be appreciated. Have a nice new big end and do not want to wreck it!

[john.nash]

Hi,

This is from an owners manual.
Do you have one ? There are a couple in the library:

http://www.arielownersmcc.com/members ... Guides.htm

The plug should come out with a pair of long nosed pliers. Just grip it and wiggle it. Catch the ball bearing and spring.
Maybe replace the spring with a new one ? Clean and juggle it all back in (spring, ball, plug). Replace the plug the same way, i.e. push home with pliers - should be an interferance fit

All I did with my pump was to clean it and replace both springs and balls.
Draganfly do an exchange on your pump, for a reconditioned one, if the plungers/bore are that bad:
http://www.draganfly.co.uk/shop/pd-1412 ... goryId=146

cheers

[brenton.roy]

Don't forget the tap - with a small hammer! and drift - to seat the ball properly.

[nevhunter]

The purpose of the ball and spring is to replace the assembly that was external in the earlier singles. These motors had an oil pressure gauge, and the ball and spring made the back pressure that the gauge measured. In the later OHV models there is no oil gauge but the back pressure provides a supply of oil to the rocker bearings. If the assembly is put together wrong or blocked up you will get no oil to the big end, and hardly anywhere else, and the pump would be overloaded. Spring in first then the ball and the little hollow bush?... Fiddly thing really. Nev.