Author Topic: Oil filter bolt question CB750 (Read 3208 times)

BobR · « **on:** May 06, 2018, 03:51:12 PM »

Got a new oil filter housing bolt for my CB750K4 with an F2 engine. The bolt is different inside where the bypass valve is. My old one has a line up of valve/spring and retaining pin. The new one has it the opposite. Spring in first, valve and retaining pin. Did I buy the wrong one or has PO messed with my original? TIA, Bob

Bodi · « **Reply #1 on:** May 06, 2018, 04:27:57 PM »

The top one is correct. The valve piston should block flow from the holes nearest the bolt head through to the second set of holes, you can see it is blocking the second set. There's a smaller diameter to the center hole where the piston is stopped - it can't go further in. The spring is against the pin. If filter pressure drop gets high enough to force the piston down against the spring because the filter is blocked by crud (like maybe the filter hasn't been changed for rather a long time), oil can then flow between the end and second sets of holes and bypass the filter.
With the parts reversed, you bypass oil all the time and the filter is useless.

BobR · « **Reply #2 on:** May 06, 2018, 04:40:52 PM »

Ok I see. If it cant make it thru the filter it goes thru the top holes forcing the valve down, out the second holes and back into the bottom holes into the engine.
So the aftermaket bolt is a POS. Wonder how many have just put them in without looking too closely , effectively eliminating the oil filter? : o. Thank you for the explination! Bob

PeWe · « **Reply #3 on:** May 06, 2018, 09:44:38 PM »

Possible to correct a wrong one? Remove pin and assemble in correct order.
I have to check the aftermarket big headed bolt I have somewhere in the garage.

Edit:
I found mine. It seems to be done in correct order. spring under the pin.
This assembly can be wrong independent of make, right? A person do it in wrong order where they are manufactured.

BobR · « **Reply #4 on:** May 07, 2018, 01:43:59 AM »

Quote from: PeWe on May 06, 2018, 09:44:38 PM

Possible to correct a wrong one? Remove pin and assemble in correct order.
I have to check the aftermarket big headed bolt I have somewhere in the garage.

Edit:
I found mine. It seems to be done in correct order. spring under the pin.
This assembly can be wrong independent of make, right? A person do it in wrong order where they are manufactured.

Perhaps but I wouldnt with mine. The valve inside was too cheap looking -dont trust it. Yours may be of better quality. Bob

PeWe · « **Reply #5 on:** May 07, 2018, 09:21:46 AM »

Quote from: BobR on May 07, 2018, 01:43:59 AM

Quote from: PeWe on May 06, 2018, 09:44:38 PM
Possible to correct a wrong one? Remove pin and assemble in correct order.
I have to check the aftermarket big headed bolt I have somewhere in the garage.

Edit:
I found mine. It seems to be done in correct order. spring under the pin.
This assembly can be wrong independent of make, right? A person do it in wrong order where they are manufactured.

Perhaps but I wouldnt with mine. The valve inside was too cheap looking -dont trust it. Yours may be of better quality. Bob

This little detail can cause an expensive repair. Really good find!
Everyone with this kind of bolt should do a filter change direct and inspect the bolt.

pjlogue · « **Reply #6 on:** May 07, 2018, 10:36:16 AM »

Quote from: Bodi on May 06, 2018, 04:27:57 PM

The top one is correct. The valve piston should block flow from the holes nearest the bolt head through to the second set of holes, you can see it is blocking the second set. There's a smaller diameter to the center hole where the piston is stopped - it can't go further in. The spring is against the pin. If filter pressure drop gets high enough to force the piston down against the spring because the filter is blocked by crud (like maybe the filter hasn't been changed for rather a long time), oil can then flow between the end and second sets of holes and bypass the filter.
With the parts reversed, you bypass oil all the time and the filter is useless.

I don't know if this is correct. This picture shows the 2 right (bolt head) holes being blocked. Where would the oil pressure force come from to move the piston to divert the oil flow?

In the OP's picture (top bolt, pic. #2) it looks as though the piston is not being fully pushed to the end of the bolt so one set of holes at the head end of the bolt is "open" either the spring is worn/broken or the bore of the bolt has a burr preventing movement.

-P.

PeWe · « **Reply #7 on:** May 07, 2018, 11:43:32 AM »

Another photo with same new oil filter bolt that look good. Now together with an old big headed one.
Red tube to visualize the hole, there are 4 holes.
Valve inside can be pressed to the threads against the spring and reveal the next row of 4 holes, IF I have got it right when reading the earlier post by Bodi

The faulty one has the spring visible on wrong side and all 2x4 holes open.

BobR · « **Reply #8 on:** May 07, 2018, 01:15:51 PM »

Quote from: pjlogue on May 07, 2018, 10:36:16 AM

Quote from: Bodi on May 06, 2018, 04:27:57 PM
The top one is correct. The valve piston should block flow from the holes nearest the bolt head through to the second set of holes, you can see it is blocking the second set. There's a smaller diameter to the center hole where the piston is stopped - it can't go further in. The spring is against the pin. If filter pressure drop gets high enough to force the piston down against the spring because the filter is blocked by crud (like maybe the filter hasn't been changed for rather a long time), oil can then flow between the end and second sets of holes and bypass the filter.
With the parts reversed, you bypass oil all the time and the filter is useless.

I don't know if this is correct. This picture shows the 2 right (bolt head) holes being blocked. Where would the oil pressure force come from to move the piston to divert the oil flow?

In the OP's picture (top bolt, pic. #2) it looks as though the piston is not being fully pushed to the end of the bolt so one set of holes at the head end of the bolt is "open" either the spring is worn/broken or the bore of the bolt has a burr preventing movement.

-P.

I had to visualize how the set up works. The set of holes closest to the head of the bolt are outside the filter when its installed in the housing. With the second set of holes blocked it has no way of bypassing. If the filter gets plugged the oil then has enough pressure to push the valve open exposing the second set of holes. It then goes though the second set of holes and into the bottom holes back into the engine.
With the new faulty bolt it would do that all the time. Bob

BobR · « **Reply #9 on:** May 07, 2018, 05:16:28 PM »

Quote from: PeWe on May 07, 2018, 09:21:46 AM

This little detail can cause an expensive repair. Really good find!
Everyone with this kind of bolt should do a filter change direct and inspect the bolt.

I totally agree and why I started another warning thread about it. Thing is its rather insidious since there is no warning that anything is wrong. Might take quite some time to slowly rack up the damage too- then its too late. Bob

pjlogue · « **Reply #10 on:** May 07, 2018, 05:39:00 PM »

Quote from: BobR on May 07, 2018, 01:15:51 PM

Quote from: pjlogue on May 07, 2018, 10:36:16 AM
Quote from: Bodi on May 06, 2018, 04:27:57 PM
The top one is correct. The valve piston should block flow from the holes nearest the bolt head through to the second set of holes, you can see it is blocking the second set. There's a smaller diameter to the center hole where the piston is stopped - it can't go further in. The spring is against the pin. If filter pressure drop gets high enough to force the piston down against the spring because the filter is blocked by crud (like maybe the filter hasn't been changed for rather a long time), oil can then flow between the end and second sets of holes and bypass the filter.
With the parts reversed, you bypass oil all the time and the filter is useless.

I don't know if this is correct. This picture shows the 2 right (bolt head) holes being blocked. Where would the oil pressure force come from to move the piston to divert the oil flow?

In the OP's picture (top bolt, pic. #2) it looks as though the piston is not being fully pushed to the end of the bolt so one set of holes at the head end of the bolt is "open" either the spring is worn/broken or the bore of the bolt has a burr preventing movement.

-P.

I had to visualize how the set up works. The set of holes closest to the head of the bolt are outside the filter when its installed in the housing. With the second set of holes blocked it has no way of bypassing. If the filter gets plugged the oil then has enough pressure to push the valve open exposing the second set of holes. It then goes though the second set of holes and into the bottom holes back into the engine.
With the new faulty bolt it would do that all the time. Bob

Yes, the holes in PeWe's photos would work as the piston allows the oil to get at the top hole (hole closest to hex end of bolt) This photo here has both sets of holes blocked by the piston and the oil pressure can't move the piston to allow bypass of the filter.

-P.

BobR · « **Reply #11 on:** May 07, 2018, 06:06:34 PM »

@pjlogue- that bolt looks OK. The top holes arent blocked that I can see. Looks that I can see thru the top hole and am looking at part of the hole on the other side ,no?

Besides the issue I'm talking about is receiving a bolt with the line up backwards. I would hate to have people get more confused.Bob

pjlogue · « **Reply #12 on:** May 08, 2018, 01:04:14 AM »

I stand corrected Bob. Upon closer inspection I see it is the plastic of the bag behind the top holes and it is very close in color to the plug. I guess I'm getting old and my eyes are becoming geezerly.

-P.

fxef79 · « **Reply #13 on:** May 07, 2021, 10:25:05 PM »

Wow.

Didn’t cross my mind that they might be assembled entirely wrong.

Will be checking all mine THIS weekend!

Sent from my iPhone using Tapatalk

bryanj · « **Reply #14 on:** May 07, 2021, 11:38:20 PM »

Not only aftermarket can be wrong, a nos honda 500 four oil pump recently had the pressure relief valve assembled wrong and mad enough pressure toexplode the filter housing

Little_Phil · « **Reply #15 on:** May 08, 2021, 03:00:12 AM »

Lots were sold 17mm head.
4into1 still shows incorrect type: https://4into1.com/honda-kawasaki-oil-filter-bolt-cb400-500-550-750-900-1100-cbx-gl1000-1100-1200/

The Lone Builder · « **Reply #16 on:** March 14, 2024, 04:15:30 AM »

Is there a way to check that this valve is working, preferably without taking the thing apart?

What keeps the valve from falling back towards the head or attached to the spring?

How can you check that the valve is not seized?

BenelliSEI · « **Reply #17 on:** March 14, 2024, 05:32:28 AM »

Quote from: The Lone Builder on March 14, 2024, 04:15:30 AM

Is there a way to check that this valve is working, preferably without taking the thing apart?

What keeps the valve from falling back towards the head or attached to the spring?

How can you check that the valve is not seized?

I suspect the bore is smaller near the bolt head.

BenelliSEI · « **Reply #18 on:** March 14, 2024, 05:34:04 AM »

So glad you pulled this out of the past. I think I have one of these on my K6 project. Will be checking it today!

The Lone Builder · « **Reply #19 on:** March 14, 2024, 06:21:58 AM »

I just fiddled a bit more.

With a small screwdriver it is possible to move the valve side-to-side. Then i was also able to rotate it.

So since it's not seized, and presumably the spring is OK as it is not under any pressure normally, I'm banking on it being OK.

MauiK3 · « **Reply #20 on:** March 14, 2024, 08:03:20 AM »

Weird thing, can't trust anything.

BenelliSEI · « **Reply #21 on:** March 14, 2024, 09:44:10 AM »

Quote from: MauiK3 on March 14, 2024, 08:03:20 AM

Weird thing, can't trust anything.

Yes! I just popped the one on the K6 loose and left it to drain. I’ve only run it for 10 minutes so far and will have a close look before sync. the carbs, for sure!

BenelliSEI · « **Reply #22 on:** March 14, 2024, 01:34:00 PM »

Created enough paranoia that I pulled mine out. It’s a “new” 17mm head part that came with a bunch of other stuff I bought ages ago. It was all assembled correctly. Phew.

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Author Topic: Oil filter bolt question CB750 (Read 3208 times)