Author Topic: Is there supposed to be some gasket here...  (Read 777 times)

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Offline BARKER

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Is there supposed to be some gasket here...
« on: September 22, 2016, 09:46:14 am »


This is on the left hand side of my 74' CB750K, between the crank case and the cylinder block (proper term?).

I had the bike out for a short ride yesterday and noticed there was a little oil weeping out from somewhere in this area.

It looks to me as though a piece of the gasket is missing in the center of this picture.

I'm new to the CB750 and I'm looking for some confirmation that this gasket has expired.  :P
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-1974 CB750K Project
-1987 Toyota AE86

Offline flybox1

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Re: Is there supposed to be some gasket here...
« Reply #1 on: September 22, 2016, 09:51:36 am »
looks like a cutout to use when you carefully pry the cyls from the case.
clean and dry it.
Ride again and see if it reappers.
'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)
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Offline Ericcb750

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Re: Is there supposed to be some gasket here...
« Reply #2 on: September 22, 2016, 10:31:29 am »
Hey Barker, I know for a fact on my Vesrah head gasket, on the left and right sides there is a tiny little cutout, about 1/4 - 3/8" long and about 1/4" deep , never really knew what they were for but i'm not 100% positive about the base gasket. Maybe try googling photos of the base gasket and see if the others have it?

I have a set at the house and when i get off work i'll check it out for you to see. Hope this helped a bit.
1978 CB750K
1978 CB750F super sport
2005 Sportster 1208

Offline BARKER

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Re: Is there supposed to be some gasket here...
« Reply #3 on: September 23, 2016, 04:18:36 am »
there is a tiny little cutout, about 1/4 - 3/8" long and about 1/4" deep

A quick google search shows that there IS a cutout in that area. Further leak detection checks is required... thanks guys
My YouTube Channel (contains CB750 stuff!)

-1974 CB750K Project
-1987 Toyota AE86

Offline evanphi

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Re: Is there supposed to be some gasket here...
« Reply #4 on: September 23, 2016, 07:11:19 am »
Use some baby powder on the areas you suspect a leak. It'll keep the oil in one spot when you run the bike again.
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive