Precision Blend Oiling System Check Valves (2004 175 VMAX HPDI)

[Captainchinewalk]

Hi, in the process of starting to reassemble my 2004 VMAX after #5 piston failure, whilst preparing for assembly I have been checking all the various oiling points on the engine.

6 Check Valves on the intake block above the reeds, one failed & 5 good although with some leak down during test with mityvac. (PN 650-11370-01)

6 Check Valves on the intake side of the engine block all tested good (PN 650-11370-01)

all of the above matches the parts diagrams perfectly, tells me its a check valve and testing shows it’s correct ……..AND now the confusing part………

6 Check Valves located on the cylinder block (PN 646-11370-01) all these are supposed to be check valves however when I test them all of them have no resistance to either pressure of vacuum.

Can someone confirm if these are in fact meant to be Check Valves?, if so why would they all have failed?

Many Thanks for the help.

[99yam40]

if you cannot find someone to answer that question, you might have to order one to see if it is really a check valve and not a mistake in the way they labled them.
Look at where the tubing goes from each of them, if they hit other check valves, there is no use in having both ends as check valves.
just my thoughts

[Captainchinewalk]

Thanks 99yam40.

Yes, I’ve considered just buying one & I’ve certainly had a close look at the other parts of the system.

I think the biggest question I have in all this is given that Yamaha tells me they “should” be check valves (I did find pictures of the correct part numbers online and they appear to be valves), why have all 6 of mine failed? What would cause such a thing……….

Hopefully the forum has some Yamaha techs floating around that can offer an opinion…….

[99yam40]

Rodbolt 17 was the only one I remember that was a Master tech,
but he is not hanging around here anymore

[boscoe99]

Although called a check valve by Yamaha, I don't think they are. Something lost in the Japanese to English translation;.