Author Topic: Oil filter bolt  (Read 668 times)

Offline Athame57

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Oil filter bolt
« on: September 18, 2026, 10:47:49 PM »
Is there actually a torque setting for the oil filter bolt? I know it shouldn't be tightened as much as other bolts, but I always seem to get a mess start to develop over time between the housing and the lower part of the crankcase ...too loose?  ::)
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1978 CB400F2 named Elen.

Offline taysidedragon

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Re: Oil filter bolt
« Reply #1 on: September 19, 2026, 12:30:36 AM »
I just do it up gently, a bit more than hand tight and never have a problem.  Make sure the joint faces are spotlessly clean and always use a new oring.
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Offline Bryanj

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Re: Oil filter bolt
« Reply #2 on: September 19, 2026, 07:15:05 AM »
There is anecdotal evidence in US that some pattern oil filter O rings are smaller in cross section so tend to leak

Offline Athame57

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Re: Oil filter bolt
« Reply #3 on: September 19, 2026, 07:43:59 AM »
There is anecdotal evidence in US that some pattern oil filter O rings are smaller in cross section so tend to leak

That might be the answer Bryan, as I've tended to do like Tay said. The new oil filter I have here is HIFLO FILTRO HF401. I've been using these a while now. Looks good, I hope it is.
« Last Edit: September 19, 2026, 07:45:45 AM by Athame57 »
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Offline exvalvesetdabbler

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Re: Oil filter bolt
« Reply #4 on: September 19, 2026, 10:01:40 AM »
I have used the hiflo filters for the last 3 years and no leaks. Just tighten the bolt until you feel the oring is being compressed and you then feel the housing bottom out on  the engine then nip it up a little, probably <1/8 turn.  I would guess 6 ft/lb at the most.

The OEM bolt that had a small hex was prone to rounding off when folk overtightened them.

For me, 6ft/lb is a short ring spanner, thumb on the nut and two fingers  half way along the
spanner.

Regards
Dave

Offline Skoti

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Re: Oil filter bolt
« Reply #5 on: September 20, 2026, 08:02:50 AM »
I have used the hiflo filters for the last 3 years and no leaks. Just tighten the bolt until you feel the oring is being compressed and you then feel the housing bottom out on  the engine then nip it up a little, probably <1/8 turn.  I would guess 6 ft/lb at the most.

The OEM bolt that had a small hex was prone to rounding off when folk overtightened them.

For me, 6ft/lb is a short ring spanner, thumb on the nut and two fingers  half way along the
spanner.

Regards
Dave

I've heard it said that the OEM filter bolt was deliberately designed with a smaller head to help prevent over tightening.

Been also using HiFlo filters, I note they now have German TUV approval which seems fairly a stringent quality test.



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Offline exvalvesetdabbler

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Re: Oil filter bolt
« Reply #6 on: September 20, 2026, 10:24:22 AM »
Yes people did round off the bolt, then used mole grips to complete the rounding off.

George, if you have had leakage it might be worth checking the filter housing on a flat surface or on the engine to verify it sits flat and hasn't been distorted.  Bit of a long shot, I know but it costs nothing to check next time you do a filter change.

Regards
Dave

Offline Bryanj

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Re: Oil filter bolt
« Reply #7 on: September 20, 2026, 04:13:53 PM »
Yes Honda only had a 12mm head to stop overtightening and yes they got rounded off because people usd cheap 12 point sockets, all you needed was a whitworth socket to hammer onto the hex and they undid no problem

Offline Athame57

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Re: Oil filter bolt
« Reply #8 on: September 20, 2026, 05:52:29 PM »

George, if you have had leakage it might be worth checking the filter housing on a flat surface or on the engine to verify it sits flat and hasn't been distorted.

Good idea Dave. I'll also check for anything on the contact surfaces that may be compromising oil tightness. This is a mega slow leak though, not even any drops on the parking spot, it's just an eye sore mucky surface.
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1978 CB400F2 named Elen.

Offline Oddjob

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Re: Oil filter bolt
« Reply #9 on: September 25, 2026, 05:30:57 PM »
Oil filter bolt torque is 19.5 - 23.8 ft lbs.
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Offline Athame57

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Re: Oil filter bolt
« Reply #10 on: September 26, 2026, 08:50:03 AM »
Oil filter bolt torque is 19.5 - 23.8 ft lbs.

That's it then, time to get a torque wrench!  ;)
I brake for animals!
1978 CB400F2 named Elen.