Topic: CB750KO - Caliper pin problem

[Steve F]

This would be my fix, as vibration has egged out the holes.

Ream or bore the swing bracket and the alum bracket that bolts to the fork (may only have to do the top on that one. Adjustable Ream or bore till it cleans up ar atleast 85%.

Then machine a new pin out of stainless, and add a grease or oil hole near the top of the swing bracket or grease it once in a while.

 i bet some people WASH IT REALLY REALLY GOOD at the car wash or with a pressure washer.. cuase there was a bit of seepage there.. that will surely make the problem worse..

Added.. checked one today.. the swing bracket could be bored and bushed, if the pin has not worn in the bracket. The one I looked at the pin was sticking in the swing bracket and pivoting in the  c shaped bracket.

Back on this subject - Is stainless steel hard enough to make a new pin from or should I have one machined in steel and then hardened?

Stainless is fine. again, no need to harden.  I was thinking of making some thin walled bronze bushings for mine after I ream the holes and maybe make a new pin too if it's worn unevenly.

[754]

I was looking at one, I think it needs a grease nipple, the whole problem is, it never gets lubed..

[Old Scrambler]

Nice thread and I understand you are dealing with PO maintenance problems. I usually hit that pin with Teflon spray after a wash or ride in the rain. No rattles yet.........after 37 years and about 65,000 miles. Frank's fix will be applied to my K2 build.   

[AshimotoK0]

I have had a CAD drawing done for an oversize caliper pivot pin for the CB750K0/K1/K2 if anyone is interested. I am getting on made in Stainless Steel and reaming the hole in the arm and brackets out to 11mm. the standard pin is NLA from Honda and I don't even think Yamiya sell a repro one

[nippon]

I made a new stainless steel pin and a bronze bushing for the aluminum bracket two years ago.
I'm pretty sure that there is not that much power on the pin to make a steel pin necessary.
I guess, if you do not use a bushing,....the soft aluminum bracket will be opened up again after thousands of miles.
So far, no clunks anymore.

nippon

[Johnie]

As you may note I started this post back in February 2008 on my KO project. I never did fix it, but instead tightened the screw tension on the front pads a bit which helped some. But the noise is still there just not as bad. Is there someone willing to make some of those pins and bushings and offer them to the members with some profit of course for time, materials, etc. Appears to be a popular problem, but many of us do not have the tools to fabricate pins and bushings. I would still have to have the bracket drilled by someone.

[Simpson]

As you may note I started this post back in February 2008 on my KO project. I never did fix it, but instead tightened the screw tension on the front pads a bit which helped some. But the noise is still there just not as bad. Is there someone willing to make some of those pins and bushings and offer them to the members with some profit of course for time, materials, etc. Appears to be a popular problem, but many of us do not have the tools to fabricate pins and bushings. I would still have to have the bracket drilled by someone.

Suprised you can't find an OEM used replacement on ebay.
You could always shell out the big bucks.
http://www.yamiya750e.com/index.php?main_page=product_info&cPath=33_86&products_id=361

[Johnie]

Agreed...Yamiya at $305 is pretty steep. I have seen them on eBay, but I have used and don't need another which will probably have the same problem. I like the idea of new pin and bushing.

[754]

If I ever build oversize pins, I will try to put a grease nipple in.. the bottom would be good..hmmm.. wonder if they make them in 1/16 pipe thread..?

[Steve F]

If I ever build oversize pins, I will try to put a grease nipple in.. the bottom would be good..hmmm.. wonder if they make them in 1/16 pipe thread..?

Most grease nipples are 1/16 pipe thread, and you can get them with just about ANY thread you want, even some that get pressed in.  Unless you leave internal space for the grease to get pumped in, a grease fitting would be ineffective and you just blow out the o-rings.  Just my opinion.  I'll stick to disassembly and packing w/ grease.

[754]

I looked yeasterday at a 1/4 NF nipple, that would work..
 No need to blow anything out, an 1/8 or 14 stroke of the grease gun will put new grease on the pin surface.. no need to grease up the rotor.

[hahnda]

Found this in a stack of Honda Service Bulletins I have.

[Johnie]

I saw that bulletin, but I could not get a spacer in there. No enough room.