Oil pressure bypass valve.
 

Im not sure if the SV has one... but im wondering if in general people have had issues with these? I think im having problems with mine being jammed open! Grrr.

Basically im getting the oil warning light on when below 2000RPM at warm running. I believe that something might have made my oil bypass valve stick open and is causing this pressure leak.

Other possibilities could be pressure sensor which I will look at and big end failure. I REALLY hope its not the latter :(

If its the oil pressure bypass thingy then I got some stripping to do... and unfortunately not the sort to involve clothes :(

Cheers for any info on this fella's (ladies :))

Re: Oil pressure bypass valve.
 

Yes, the SV has a pressure relief valve.
I have once suspected a valve had a broken spring/stuck plunger, but the engine had high miles so it was replaced rather than stripped - as you may know the sump on the SV is not separate so the motor would need to be removed and the cases split to gain access to the valve.
I doubt the pressure relief valve would cause the symptoms you describe, it's a simple device, just a plunger that will be pushed back against a spring when the oil pressure rises high enough to overcome the strength of the spring. Higher revs means higher pressure, thus at low speed the valve won't operate but will vent excess pressure when at high revs. If the valve were stuck open or the spring broken there would be no oil pressure at all, and thus the oil light would be lit constantly. Even if the spring were weakened the valve would still operate at a given pressure, and that would be constant, so the problem would be low oil pressure at all engine speeds, not just low speeds.
I'd check the pressure switch by substitution first, if that doesn't solve the problem then you'll need to find a suitable gauge to find out precisely what's happening with the oil pressure.

Re: Oil pressure bypass valve.
 

Fair enough. Lets hope its just the pressure switch then.

What sort of pressure guage do I need to buy, Ive seen air pressure guages for testing pistons etc at halfords, don't suppose that's the same sort of thing?

The engine in its self sounds normal. No rattle from the top and and tensioners and as yet no bottom end knocking. Just hope it is as simple as the switch! Dont fancy having to put in a new motor tbh. :rolleyes:

Re: Oil pressure bypass valve.
 

Is this on your Falco ?

My brother had similar problems on his RSVR Millie, he never got the bottom of it, despite taking the motor apart and fitting new oil pump etc etc.

I need to ring him later and I can ask him what he did might save you some time. I know he found some articles on the RSV forum that gave him loads of stuff to try.

Re: Oil pressure bypass valve.
 

The pressure switch is a very simple device and they're certainly not known for failing - but I have seen it happen, and if as you say it's running OK otherwise, I'd say there was room for optimism. Probably easiest to get somebody suitably equipped to test the oil pressure - the relevant gauge and connection adaptors would be expensive items for one-off use.

Re: Oil pressure bypass valve.
 

Cheers Fizz. I have searched on there and there are a few cases that are similar. If he went to a lot of trouble like he seems to have then that is very odd!

OK sid, ill have to find a shop local that can do that for me. Taa.

Re: Oil pressure bypass valve.
 

just to back up what Sid says, I've had oil pressure switches fail (not on the SV, on my BMW in the Alps, quite worrying when it happens!) so it isn't unknown, and it's by far the cheapest thing to change. Hope that's all it is.

Re: Oil pressure bypass valve.
 

Yea, the thing that doesn't make sense is that its at pretty much exactly 2100rpm that it does it when warm and the temp (viscosity) makes a difference... Wouldn't have thought a buggered switch would do that?

We shall see. Will let you know for interests sake as soon as I know.

Any more idea's then feel free to voice them! :cool:

Re: Oil pressure bypass valve.
 

Well changed the Oil pressure switch and no go! :(

Ill be taking the side off of the motor soon to check the pumps etc. Joy. Just what I need, to strip the damn engine down! :thumbdown:

Re: Oil pressure bypass valve.
 

Damn it Nick, just sell that bike!










And buy another Falco :)