Oil Bypass Spring

[TitanMonsterS4R]

Changing the oil and when I went to remove the oil filter it wouldn't budge.  Took a little more work and finally got the filter unscrewed, however, in the process the bolt and the bypass spring (#14) came with it.  Didn't notice the spring.....FAST FORWARD.  Screwed the bolt back in, filled the bike with oil and took her for a spin.  When cleaning, came back and noticed the bypass spring.  



What purpose does it serve and did I do any short/long term hard by riding her for about 30 minutes?

[stopintime]

From the workshop manual (is this what you're talking about?)

Note
Should the oil cooler be blocked
or frozen, oil pressure will increase
thus opening the reed (Q) on the
cartridge filter (R). Should this be the
case, oil will reach the cartridge filter
(R) without flowing through the
cooler.

[ducpainter]

It's to divert the oil directly through the filter and bypass the cooler when the oil is cold and thick.

You did no harm.

When you re-install make sure the tab blocks off the round hole. The tab will be in between the raised bosses.

[TitanMonsterS4R]

Just curious, could one operate permanently without the spring or is the spring necessary to properly filter the oil?  Electronics are my thing, not engines.....

[ducpainter]

Just curious, could one operate permanently without the spring or is the spring necessary to properly filter the oil?  Electronics are my thing, not engines.....

It won't affect filtration.

Depending on the cold pressure your engine develops I suppose it's possible to damage the cooler. It will also slow the warmup of the engine.

[TitanMonsterS4R]

It won't affect filtration.

Depending on the cold pressure your engine develops I suppose it's possible to damage the cooler. It will also slow the warmup of the engine.

Since it's summer here, it doesn't get colder than 75 in DC.  Just learning......Why would it damage the cooler because oil wasn't being passed through?  If that's the case, would the engine run hotter than normal?

[rule62]

It's to divert the oil directly through the filter and bypass the cooler when the oil is cold and thick.

When I added an oil cooler to my 620, I was told that the spring is necessary to make sure oil is routed to the cooler. I was told that without the spring, the oil would not be routed through the lines to the cooler and the cooler would then be about as useful as a paperweight. Ducpainter's post pretty much inverts that idea. Interesting stuff for anyone wanting to add a cooler to a smaller Duc.

I'm still pretty sure the spring is needed to ensure the cooler is allowed to do its job.

[ducpainter]

Since it's summer here, it doesn't get colder than 75 in DC.  Just learning......Why would it damage the cooler because oil wasn't being passed through?  If that's the case, would the engine run hotter than normal?

It might damage the cooler because the oil pressure, when cold, was too high for the construction of the cooler and could cause it to leak.

I'm not saying it would, but there has to be a reason the engineers added it.

The spring is supposed to stop flow to the cooler so the oil can warm up quicker and flow more freely to the vital engine parts.

When I added an oil cooler to my 620, I was told that the spring is necessary to make sure oil is routed to the cooler. I was told that without the spring, the oil would not be routed through the lines to the cooler and the cooler would then be about as useful as a paperweight. Ducpainter's post pretty much inverts that idea. Interesting stuff for anyone wanting to add a cooler to a smaller Duc.

I'm still pretty sure the spring is needed to ensure the cooler is allowed to do its job.

I've been wrong before.

...but why would it be called a bypass spring?

If the OP has no spring it would be nice to know if his cooler gets warm when he runs the engine.

That would solve the mystery.

[rule62]

If the OP has no spring it would be nice to know if his cooler gets warm when he runs the engine.

That would solve the mystery.

I hope my last post wasn't insinuating. I didn't intend it that way at all.

I'd also like to know if the cooler gets oil without the spring as you've posted above.

[ducpainter]

I hope my last post wasn't insinuating. I didn't intend it that way at all.

I'd also like to know if the cooler gets oil without the spring as you've posted above.

Not at all. 

I'm posting my understanding of the way it works.

If I'm wrong I'll be the first to admit it.

If the OP can start his bike and let us know it will be great.

[stopintime]

Let me try to add some uneducated info...  It's there to ensure oil flow even if the cooler is blocked by 'frozen' oil. It's a valve that opens when/if the pressure is as high as it gets with a blocked cooler.

I don't know if it stays open or shuts down without the spring.

Isn't that the part that needs to be modified when you install a cooler on a non-cooler bike?

[ducpainter]

Let me try to add some uneducated info...  It's there to ensure oil flow even if the cooler is blocked by 'frozen' oil. It's a valve that opens when/if the pressure is as high as it gets with a blocked cooler.

I don't know if it stays open or shuts down without the spring.

Isn't that the part that needs to be modified when you install a cooler on a non-cooler bike?

I believe it needs to be added.

[TitanMonsterS4R]

I believe it needs to be added.

I haven't put hte spring back in yet, what would you like to be tested?  Whether the oil cooler gets warm without the spring inserted?

[rule62]

I haven't put hte spring back in yet, what would you like to be tested?  Whether the oil cooler gets warm without the spring inserted?

Yes

[ducpainter]

I haven't put hte spring back in yet, what would you like to be tested?  Whether the oil cooler gets warm without the spring inserted?

Please.