Topic: Swing Arm ID and help

[wyowill]

Hi All,

I could use a little help with the rear fork / swing arm on my 1976 cb750k.  I purchased it a couple months ago and don't know much about it's history--except that I've already discovered a few botch jobs on other parts of the bike so at least one of its prior owners was a piss-poor mechanic.  Anyhow, I noticed a TON of side-to-side slop in the rear swing arm so I took it apart and disassembled to investigate.  I've attached a picture of everything that was on the bike.

What year and model is this swing arm from?  It appears to be from a cb750F according to the figure in my Clymer manual since the grease fitting is in the middle instead of on the end of the pivot bolt.

If it is a cb750F swing arm, am I okay using it on my cb750K?  I think so, but this my first cb750 project so I could be wrong.

If so, what parts do I need to get this back together properly?  Everything that was on the bike is in the picture.  I'm thinking I should get: (1) a new center collar, (2) bronze bushings, (3) dust seal caps, and (4) a pivot bolt washer.

Any other advice or input welcome.  Who knows how the prior owner rode this since the pivot bolt was pivoting solely on the dust caps!?!?!!!  I'm sure glad I decided to do a deep dive on the bike before riding it!

Thanks all!

[seanbarney41]

It is not from an F.  The F has a much different brake stay for the disc brake caliper.  I don't remember exactly what year the grease point changed from the ends to the middle...k5,k6?  Anyway, you have a K6, so looks correct to me.

[754]

Nipple or Zerk and plastic bushings make 75 or 76 I think.
 Except for the nipple, 71 to 76 look the same , except on F model.

[wyowill]

Thanks fellas.  Well, maybe a Clymer figure is wrong.  I'm looking at pages 165 and 166 if anyone cares to double check me.  My bike has rear drums and the wheels are correct to the K6, if that helps any.  The old bushings are plastic and have a collar on them.

Anyone know what center collar I might need?

[HondaMan]

That arm is the K4-K6 version. They have one grease zerk in the center, which basically...doesn't work. It also has the original phenolic bearings, a rare find these days! That doesn't mean they are good, as they usually lasted about 8000 miles from new before the grease made them spongy, or less if no one greased them.

You are missing the collar, though. I'll PM you the rest.

[bryanj]

New bronze bushes and a new collar (not cheap) and you should be ok

[wyowill]

That arm is the K4-K6 version. They have one grease zerk in the center, which basically...doesn't work. It also has the original phenolic bearings, a rare find these days! That doesn't mean they are good, as they usually lasted about 8000 miles from new before the grease made them spongy, or less if no one greased them.

You are missing the collar, though. I'll PM you the rest.

The gauges say it has 11k miles...  Of course, the bearings won't wear much if there's no center collar!

New bronze bushes and a new collar (not cheap) and you should be ok

That was my initial thought.  As you point out, it's hard to find a collar that doesn't break the bank.  Based on my research (and the expert help of this forum!) this bike should have Honda  part# 52141-390-010.

[bryanj]

The earlier 300 midle number collar will fit if you get the older bolt with a zerk at each end. I drill and tap those 6mm to fit standard zerks instead of the push in Honda ones. We call them nipples in UK by the way