Author Topic: Oil leaking from Cylinder Head Side Covers -- crush washer?  (Read 1933 times)

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Offline jorwesflow

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Oil leaking from Cylinder Head Side Covers -- crush washer?
« on: March 14, 2016, 11:39:18 am »
1977 CB550K

Anyone else every have this issue? It has to do with the crush/sealing washer 90485-001-000 being worn out. It's a slow weep/leak, but annoying nonetheless.

My current ones look like they've been put on train tracks and run over like pennies. But I cannot find this part ANYWHERE. Every single place, foreign or domestic, does not have this washer. I've ordered from places that show "in stock" only to receive an email a few minutes later saying they're backordered/out of stock. It's a 6.5mm crush washer. I've seen a somewhat comparable part 90441-028-010 (but it's  6mm, not the stock 6.5mm).

Any suggestions?

« Last Edit: March 14, 2016, 11:41:08 am by jorwesflow »
1977 CB550K

Offline flybox1

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« Last Edit: March 14, 2016, 11:54:02 am by flybox1 »
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

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Offline jorwesflow

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1977 CB550K

Offline flybox1

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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline heavenlystriker

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #4 on: April 04, 2020, 12:08:30 pm »




What program is this you are using ? I'd like to get my hands on one.

Offline jorwesflow

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #5 on: April 04, 2020, 12:32:23 pm »
What program is this you are using ? I'd like to get my hands on one.

It's a parts fiche. Can't remember exactly which one. might be bike bandit: https://www.bikebandit.com/honda-oem-parts

Here's that specific page:
https://www.bikebandit.com/oem-parts/1977-honda-cb550k/o/m9448#sch402806
1977 CB550K

Offline bryanj

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #6 on: April 04, 2020, 11:31:42 pm »
Its a common leak, change the O rings on the cover as well, here in UK we have what we call "Dowty Washers" used on hydraulic fittings which are alloy, same as original, with a rubber type insert i have had sucsess with those
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 flatlander

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #7 on: April 05, 2020, 12:01:34 am »
the guys are right, a simple copper washer will do. size difference of fractions of a mm wont' be a problem as long as an M6 bolt fits through.

Offline PeWe

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #8 on: April 05, 2020, 12:58:44 am »
eBay sellers located in UK sell these Dowty Washers.
I have recently got some M8 for crank case bolts.

UK sell lots of good stuff for OK prices.  O-rings, bearings, oil seals, Loctite, spark plugs (from green sparkplug company), bolts, nuts etc cheaper than elsewhere. Often very good shipping too.

Dowty washers can also be ordered from China.
Note! There are different qualities Viton or NBR( nitrile).
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline bryanj

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #9 on: April 05, 2020, 06:23:04 am »
If anybody finds stuff in UK that seller will not post to i will happily be a staging post for you BUT i will not carry the can if post office loose it!!!
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 flatlander

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Re: Oil leaking from Cylinder Head Side Covers -- crush washer?
« Reply #10 on: April 05, 2020, 07:20:28 am »
i have a whole bag of those 6mm copper washers.
jorwesflow: if you can't find any i'll just drop a handful in an envelope and send them over. it'll be from the netherlands but shouldn't take more than a few days in the mail. drop me a pm with your address if you want them.

Offline jorwesflow

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1977 CB550K