Pressure Relief Valve Spring

Joined
Nov 10, 2012
Messages
3,154
Country flag
Hi.
I have fit a new commando spring (without shim).
Cranckases oil ways are not machined.
Engine is all new with + 0,20 flat hepolite pistons.
Something to check?.
Thank you.
Piero
 
Don’t know what you have done precisely but the oil Pressure Relief Valve Spring should be fitted with the suitable spaces, or you will have VERY high oil pressure coming out of the timing cove oil line :!: :shock:
 
Bernhard said:
Don’t know what you have done precisely but the oil Pressure Relief Valve Spring should be fitted with the suitable spaces, or you will have VERY high oil pressure coming out of the timing cove oil line :!: :shock:

What exactly do you mean by "suitable spaces"(spacers)? :?
If you mean OPRV shims, then fitting additional shims increases the relief oil pressure.
 
Nobody seems to know much about these things. I have heard that you are supposed to have one dry and shake it next to your ear and if it rattles, it's good. That seems imprecise. I built a jig to test them but discovered there is so much slop on the 2 or 3 threads mounting the OPRV to the case that oil flows past the threads quite easily. I don't think anyone knows how many shims to put in, I've seen none and up to 4. Who knows. I bought a new one from SRM and crossed my fingers. They swear they have been tested but who knows. I also put a gauge on the bike. 40 PSI cold.
 
Nobody seems to know much about these things.

o_O

I have heard that you are supposed to have one dry and shake it next to your ear and if it rattles, it's good. That seems imprecise.

It does seem rather imprecise, however, that's supposed to give approximately the correct OPRV setting as actual oil pressure doesn't appear to be that critical as the manuals give maximum oil pressure as 45-55 psi.


I don't think anyone knows how many shims to put in, I've seen none and up to 4. Who knows.

Adding or subtracting shims adjusts the OPRV vent pressure but a pressure gauge is obviously necessary to measure the change resulting from the addition or subtraction of shims.
 
Back
Top