Parts interchangeability '73 to '77 and lowering height

[Tugboat]

Hello everyone,

 I'm new to the forum. I just purchased a '77 CB750K. It only has 12K miles on it and is in overall great shape. I have a chance to buy a '73 parts bike and was wondering if it most parts are compatible or should I pass until a '77 comes along? (It doesn't need anything at the present)
Also I wouldn't mind lowering the seat height. Not sure which route to take - cutting down the seat or lowering shocks or ? I don't want to make any changes that would dramatically effect the handling or could not be undone to keep it original.
Any input would be appreciated. Thanks

[Lucky 1]

The 1977 is very different that the 73.
The 1977 had the most improvements in the engine of all of the SOHC CB750's
There were about 21 improvements, but I am not going to list them all.
The cam chain tower was wider.
What i am saying is many engine parts would not be interchangeable.
The 1977 had the accelerator pump system on the carbs BUT at
least the needles on the slides were still adjustable.

The 1977-78's had the longest swing arms of all the SOHC CB750's

To lower your bike the fastest and easiest way is to get shorty shocks for the rear.
You can get them at Cycle-x (exchange) and they are 11.4 inches.
It makes a dramatic change for a low cost. Then you can just lower the front fork tubes
in the trees 1 inch. OR just leave them alone. Yes.. it will increase the rake very slightly.

[Tugboat]

Thanks Lucky 1 !

I'm going to order their shocks tonight.
Any posts here on lowering the front fork tubes?

Tugboat

[Lucky 1]

Easy to do . Just loosen the pinch bolts holding the fork tubes in the triple clamps.
Loosen them just enough. Then take a plastic or rubber mallet and tap downwards on the triple clamps.

Tap one side the the other side.
Be careful to not hit your instruments etc.,.

After you get them to inch sticking up re tighten the pinch bolts.

Then check the routing of your brake hose and speedo and tach cables
to make sure that they will not have a problem. Make sure no wiring is bunched up or pinched.
It should all be OK with such a minor change.

[Piute]

Lucky 1 wrote

Easy to do . Just loosen the pinch bolts holding the fork tubes in the triple clamps.
Loosen them just enough. Then take a plastic or rubber mallet and tap downwards on the triple clamps.

Tap one side the the other side.
Be careful to not hit your instruments etc.,.

After you get them to inch sticking up re tighten the pinch bolts.

Then check the routing of your brake hose and speedo and tach cables
to make sure that they will not have a problem. Make sure no wiring is bunched up or pinched.
It should all be OK with such a minor change.

                                                             

    Had mine up (1 1/4")till I cut springs N threaded down dampener(now new)old stk. shocks were shot.

[Tugboat]

Thanks again - seems like a simple solution. One more question - There's quite a few 750s around here (western NY) and I want to look for a parts bike. What years (if any) are most compatible with the '77 750K ?

[TOOLS1]

It depends on which parts, you might need. All the carbs, ignitions, charging systems, engines, wheels, frames, suspension parts, cables, and controls can be swapped between any of the 69-78 CB 750 K's, and F's. The only things that would be a problem would be tanks, seats, and side covers.
However to answer your question, since, you have a 77 K model, the best would be a 77-78 K model.
TOOLS

[SouthernAbintra]

I have a 1976 CB750F with a single rear disc brake.  I would like to replace the spoke wheels with "mag" wheels that come on the 1978 model.  Anybody know if they - or any others - will fit?

[Piute]

SouthernAbintra wrote

I have a 1976 CB750F with a single rear disc brake.  I would like to replace the spoke wheels with "mag" wheels that come on the 1978 model.  Anybody know if they - or any others - will fit?

   
                            Chrome Guy
                                                    he swaped the other way check hie tread
                                                    use" free bike "in search should work

[shinyribs]

As far as I know the wheel will swap right on. '78 and later bikes have a different spacing on the sprocket than the earlier ones. Reuse the cush drive(the part of the wheel that holds your sprocket) to retain the proper spacing. BUT,all of my spoke wheels have a 4 spoke cush drive,whereas my mas wheel has a 5 spoke cush drive. I'm still working out the kinks on this myself.

If I am wrong on any of this,someone please correct me!