Topic: Solved: Warming up the 750K, throttle stop screw tending

[rotortiller]

PeWe, The bypass situation is possible when the cold oil is too thick to  pass easily through the filter or for when the filter gets clogged.

[Tracksnblades1]

Interesting discussion.
So the oil filter bolt will bypass oil during normal use?
Normal cruising when warm, pressure around 40PSI.

I thought that bolt bypass valve should let oil outside filter when filter was so clogged that oil will not pass, or at least not enough to lubricate.

Oil with particles better than no oil.

Honda designed it as a full flow filtered system. Normal use with a clean filter at operating temperature would filter 100% of the oil.
 
There has to be a pressure differential within the filter itself. With a 21# pressure differential, as Hondaman wrote, the by pass would open allowing unfiltered oil to be added to the filtered oil to prevent catastrophic failure. Especially for those that never change oil or filters.

I’ve attached a service manual picture. It’s similar to the automotive bypass, just a different means..

Also Don R,
The picture show the oil pressure differential within the oil filter housing will increase the effectiveness of the oil filter spring you were posting about not having enough room for with the wix filter on the GL.

[Don R]

 So, if your oil pressure is 60 psi then the filter would bypass if pressure after the filter dropped to around 39 psi. Makes sense.
 

[Tracksnblades1]

So, if your oil pressure is 60 psi then the filter would bypass if pressure after the filter dropped to around 39 psi. Makes sense.

Yes.  And I If you wrote that with 60# of pressure on the outside of the filter element, the bypass would open when the pressure on the inside dropped to 39#, it would mean the same..

That’s the question that’s swimming in my mind because the oil pump regulator it set to that same 60# pressure at operating temp. Actually the main regulator is set at 56.9 psig @ 4000 rpm @ 176*F operating temperature according to the manual. But, Mine reads 60# also when hot..

But where we screw the oil pressure gauge into is the oil galley (filtered) oil…

[rotortiller]

Here are typical psid (differential pressure) bypass valve values for various filters used in bikes and cars.  About 4/5th the way down and it is interesting data for what it's worth.

https://motorcycleinfo.calsci.com/FilterXRef.html#BMW 

My feeling on the different bypass settings is that finer media may 'traffic jam' at a different point or more or less media surface area is present. Most engines run in a similar or general PSI range for oil pressure and that is why most bikers choose a superior automotive oil filter over the overpriced or underpriced OEM. Just because a filter has a slightly different bypass value does not make it unacceptable.

There has been in the past  spin on bike filters without a bypass employed in engines with no engine bypass feature and unlike what the sohc4 has. Because the sohc oil filter is a fixed paper media design the bypass oil filter bolt spring pressure was set with that specific media in mind by size and construction. With spin-on bike filters I choose the longest one that will fit, some peoples' SOHCs actually employ a spin on with an integrated bypass oil filter using a threaded adapter. I have never experienced a problem with (my fav) Mobil-1 substitute spin-on oil filters or alternate SOHC clone paper filters on several bikes I have and many more I have owned.

Sometimes a caution can be found in the power-sport manual about reving the engine right after cold start up causing critical damage. These full flow non-bypass filters were also used in tractors lol.  Kawasaki stopped selling a no-bypass spin-on OEM motorcycle oil filter about 8 years ago thank goodness.

Even if your filter bypasses on cold start up or at other normal operating transient situations it is simply bypassing previously cleaned oil so really it is no big deal. The thing to remember about a bypass situation is that it does not dump the crap accumulated in the filter media into the oil flow, that's why its called bypass-oil flow route around the filter media traffic jam.

[PeWe]

Thanks guys! That explained it all!

Not rev a cold engine has got another reason for me. Never had any thoughts about oil filter, only the lubrication and clearances.

Oil with particles in the oil pan that filters thru the pumps strainer. Small stuff from clutch fibers etc.

[dave500]

so back to the cold idle "throttle hold"thumb screw,i use mine on my 500 when i fire it up cold,gear up as it fast idles,then wind it off,ride away but not hard power for a few minutes,no way any old carburetted car or bike will idle straight up cold with no sort of fast cold idle arrangement or manual throttle actuation!i think anyone born since fuel injection and never used carbs much wouldnt have that feel you need for such an occurrence?in the old days it was part of learning to drive?

[Kelly E]

Back in 06' I was in school for automotive technology. I was the old guy there at 46yo and one of the teams of hot #$%* young guys were working on a Datsun 260Z. They had pretty much murdered the battery trying to start it with no success, it's a carburetted motor. I was teamed up with a sharp young gear head and he said are you going to go help them? I said no but watch this.
After it had been on the jump box for a while I snuck over there when they weren't looking. I got in the car, pulled the choke and it fired right up. Immediately I shut it off, pushed in the choke lever and jumped out of the car. They were all asking how did you do that? I told them to try reading the books instead of trying to get the internet to tell you how the car works.
They were clueless about the choke. On a Datsun 260Z the choke lever is on the side of the console by the parking brake. They never saw it.

[RAFster122s]

For many a manual transmission is an anti theft device…most kids and young adults cannot drive them.

[newday777]

Back in 06' I was in school for automotive technology. I was the old guy there at 46yo and one of the teams of hot #$%* young guys were working on a Datsun 260Z. They had pretty much murdered the battery trying to start it with no success, it's a carburetted motor. I was teamed up with a sharp young gear head and he said are you going to go help them? I said no but watch this.
After it had been on the jump box for a while I snuck over there when they weren't looking. I got in the car, pulled the choke and it fired right up. Immediately I shut it off, pushed in the choke lever and jumped out of the car. They were all asking how did you do that? I told them to try reading the books instead of trying to get the internet to tell you how the car works.
They were clueless about the choke. On a Datsun 260Z the choke lever is on the side of the console by the parking brake. They never saw it.

 Good one

[Kelly E]

For many a manual transmission is an anti theft device…most kids and young adults cannot drive them.

That's the truth. My hotrod 85' GMC S-15 is a 5sp plus a secret parking brake release and it's carburetted. The thieves don't stand a chance.

[Kaze]

First stick I ever drove was a 3 speed dump truck. I was a seasonal for the parks department. Killed it on a hill. Then restarted, put it into gear, and shook the whole goddamn truck like it was an iron earthquake. After that, it was awesome.

Motorcycles are the BEST though. Each hand and each foot has its own job. None of that moving my foot around like I'm playing a #$%*ing pipe organ.

As for carburetors, you guys ever have a car that didn't start, so you took off the air cleaner and put a screwdriver in there to hold the butterfly open? That was like... Dad car lesson 2 in my house. Lesson one was give it a bit of gas before you turn the key, but don't pump the bastard or you'll flood the som#$%*.