Author Topic: 1977 cb 550f oil pan question  (Read 888 times)

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Offline mikerider

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1977 cb 550f oil pan question
« on: November 07, 2025, 03:02:56 PM »
Do I have to take off the exhaust  pipes to get to the oil pan bolts on the exhaust side?


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Offline bryanj

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Re: 1977 cb 550f oil pan question
« Reply #1 on: November 07, 2025, 03:29:35 PM »
Probably
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline HondaMan

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Re: 1977 cb 550f oil pan question
« Reply #2 on: November 07, 2025, 06:11:46 PM »
It always seems like the #3 exhaust pipe wants to be right up against the side of the oil pan: I then loosen the #3 and #4 header clamp nuts and the rear footpeg (hanger) bolt for the mufflers and wiggle them away from the oil pan to help reach those bolts.

Don't forget to re-tighten it all afterward - like I've done more than two or three times... ;)
See SOHC4shop.com for info about the gadgets I make for these bikes.

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Offline mikerider

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Re: 1977 cb 550f oil pan question
« Reply #3 on: November 08, 2025, 09:53:16 PM »
OK that all worked out fine got the oil pan on and everything is fine with that but, I still have  a leak from the top of the oil cartridge a d runs down on the floor..  where could it be running from. 

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Offline bryanj

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Re: 1977 cb 550f oil pan question
« Reply #4 on: November 08, 2025, 11:52:10 PM »
Do you mean the oil filter housing?

If so there have been reports of some pattern oil filters having O rings of a too small cross section
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline newday777

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Re: 1977 cb 550f oil pan question
« Reply #5 on: November 09, 2025, 02:49:29 AM »
As Bryan said, aftermarket orings for the oil filter housing and the oil filter bolt are junk and are either too big or too small depending on which aftermarket oil filter you buy. I trash can the orings from any aftermarket oil filter and only use Honda orings to be sure there aren't any leaks(in all of the engine). It's been that way since the 1970s when I was a parts manager.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 1 K2, 4 K6, 1 K8, 1 F1, 1 F3
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline HondaMan

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Re: 1977 cb 550f oil pan question
« Reply #6 on: November 09, 2025, 01:56:56 PM »
In the USA, if your new oil filter came with a new large O-ring, it is 100% likely the O-ring is too thin. All the other bikes that use the filters use thinner O-rings than Honda: Honda's own is 4.5mm thick and yours is likely to be 3.5mm thick if the wrong one. I have replaced a bunch of cracked oil filter housings that broke from  frustrated owners trying to crank them tighter.

Honda's part is:
91316-425-003
O-RING (89X4.5)
See SOHC4shop.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book
Link to My CB500/CB550 Book: https://www.lulu.com/search?sortBy=RELEVANCE&page=1&q=my+cb550+book&pageSize=10&adult_audience_rating=00
Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

Offline piefairy

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Re: 1977 cb 550f oil pan question
« Reply #7 on: November 12, 2025, 06:16:18 AM »
Anyone know if the one that comes from vintage cb750 is the correct size? I have some on order with the new filter.

Offline BenelliSEI

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Re: 1977 cb 550f oil pan question
« Reply #8 on: November 12, 2025, 07:26:18 AM »
Anyone know if the one that comes from vintage cb750 is the correct size? I have some on order with the new filter.

I’ve used a few (most recently buy in bulk on EBay for 1/2 the price) of theirs and I think they worked just fine.