Topic: 1971 CB750 Fork seals same as 72 to 76?

[chewbacca5000]

I want to do an oil change and install new seals on my 71 cb750 and need to know if 72 to 76 fork seals are different than the 71s.

Thanks!

[MCRider]

I want to do an oil change and install new seals on my 71 cb750 and need to know if 72 to 76 fork seals are different than the 71s.

Thanks!

Check the parts fishies for common part numbers. They may also list the dimensions of the seals.

I think there were changes in the dimensions between K1 and K2. The ID is the same at 35mm, but the OD and the height may have changed, to make them more stable and less prone to leaking. OCICBW

[Powderman]

71&72 had a 46mm OD, that changed in 73 to a 48mm OD

http://find.partzilla.com/?s=1&q=Fork&x=-928&y=-14

[chewbacca5000]

I want to do an oil change and install new seals on my 71 cb750 and need to know if 72 to 76 fork seals are different than the 71s.

Thanks!

Check the parts fishies for common part numbers. They may also list the dimensions of the seals.

I think there were changes in the dimensions between K1 and K2. The ID is the same at 35mm, but the OD and the height may have changed, to make them more stable and less prone to leaking. OCICBW

I looked at bike bandit and they are selling the same seal for 71 and 76 71 730284 OIL SEAL (35X48X11).

Do you have a better source for part fische

[Powderman]

When I checked specific years it gives their size. When I checked 71 seals and see their cross reference to other bikes on the generic seals they show them fitting all the way through 76. Measure yours and see what they are.

[Dream750]

I want to do an oil change and install new seals on my 71 cb750 and need to know if 72 to 76 fork seals are different than the 71s.

Thanks!

Honda went to the "new style" double lip seal design for the 750 K1 and K2. The updated seal part number (91255-341-305) shown in the service bulletin below is still current and that seal size is: 35 x 48 x 13.2
 
http://manuals.sohc4.net/CB750SB/750_41.pdf

[chewbacca5000]

Thanks guys think the right thing to do is to measure first.  Looks like od is 48 according to the service bulletin. 

[MCRider]

A 35x48x11 will fit in where a 13.2 is called for. Maybe not the other way around. If the newer 13.2 will fit your leg, that'd be the one to use.
You may be able to read the dimension on the old seal, or measure the inside leg when the seal is out.

[Powderman]

A 35x48x11 will fit in where a 13.2 is called for. Maybe not the other way around. If the newer 13.2 will fit your leg, that'd be the one to use.
You may be able to read the dimension on the old seal, or measure the inside leg when the seal is out.

Not if the seal race is only 46mm. The issue isn't the thickness of the seal but the OD. The 11 will fit where the 13.2 is called for if using the spacer for the 11.

[MCRider]

A 35x48x11 will fit in where a 13.2 is called for. Maybe not the other way around. If the newer 13.2 will fit your leg, that'd be the one to use.
You may be able to read the dimension on the old seal, or measure the inside leg when the seal is out.

Not if the seal race is only 46mm. The issue isn't the thickness of the seal but the OD. The 11 will fit where the 13.2 is called for if using the spacer for the 11.

I agree. The 46mm leg was K0, but may have been a few K1s too? I was comparing 48 to 48. Always gottta check the VIN/serial numbers on the fishies.