Topic: Disassembling front forks - K1 750

[ZTatZAU]

That might work, dunno.

You will destroy the stem washer and seal, but that race is pretty thick, don't think you will damage it because you don't have a lot of room for a big drift/punch.

I clamped mine down (upside down of course), in a bench vise with wood all around the stem and wood on the bottom as not to damage the threads on top of stem.

It actually worked out great, Denward!  And while I've gotten a bit wordy again, I hope this post might help others.

I went over to a buddies shop who fabricates industrial steel to see if he might have a 1-3/8" hex nut lying around.  He did not.  But he did have some scrap 2-1/2" x 3/8" flat bar from a project he's working on and, more importantly, a Piranha steel punching machine which has always amazed me..

In about 5 minutes, he whacked off a 2-1/2" length of the 3/8" flat bar and punched a 1-5/16" hole in the center of the 2-1/2" x 2-1/2" square piece of 3/8" steel.

I took the piece home and, with Mama's blessing, put it in the oven at 400°F.  I then went back out to the shop to get everything ready... An assortment of various size screw drivers, cold chisels, punches, and hammers.

I took the old steering stem from the freezer, clamped it down on my welding table and wrapped it all in a beach towel to maintain the cold temperature, best I could.  Then I brought the hot "holed" piece of steel out from the kitchen and slid it down the stem to rest on the bottom bearing cup.  I then wrapped some pot holders around the hot tool and wrapped everything up again with the towel.  I waited five minutes, thinking that was enough time for the newly fabricated heat transfer tool to do its thing, before unwrapping everything again.  Here's the setup...



I started by sliding and tapping the smallest screwdrivers in around the perimeter of the bearing cup between the bottom of the cup and the rubber seal.  I moved on to larger screwdrivers repeating this process.  Eventually, I was able to slip the tips of a couple of cold chisels in between the cup and the seal and started tapping them in radially around the perimeter with the wedge shape of the chisel tips raising the bearing cup a little more with each tap until the chisels bottomed out against the bottom shoulder of the cup.

By now the cup was raised up high enough to let me start tapping the two chisels in further and further, tangentially on opposite sides of the stem, under the rubber seal and washer between stem and the stop lugs of the triple tree.  With a few more taps, the bearing cup, seal, and bottom washer were free...



There was no beating or banging but rather just a series of light tapping and levering the bearing cup up, a little at a time.  And while I put a few marks on the rubber seal and a couple of scratches on the bottom washer, neither was damaged to where they couldn't be used again had I intended to do so.



With nothing damaged, I can now accurately measure the height of the original bottom bearing stack to determine which, if any, of the All Balls shim washers will be required.

The next step for me now, is to remove the bottom bearing race and the top bearing cup from the goose neck pipe on the frame and start assembling my NOS steering stem with the All Balls tapered roller bearings.

Today, I'm a happy camper!
ZT (SOHC Apprentice)

[BenelliSEI]

Really polish the stem shiny clean. Warm your new bearing and freeze the stem. It will literally drop on. The clearances are not very tight.

[denward17]

Great job, glad it worked out.

[ZTatZAU]

Really polish the stem shiny clean. Warm your new bearing and freeze the stem. It will literally drop on. The clearances are not very tight.

There's no need to polish anything here John, but your advice is always well taken.

I can't expect you to read, let alone remember, everything I've written here; but you've really been missing a lot of the details in some of my recent posts.

My front end rebuild project really began with the decision to replace my original steering stem with bent and damaged steering stops to prevent any contact between my forks and the gas tank.  So I sprung for a NOS steering stem so as not to damage my new Yamiya painted body set.





These pix might refresh your memory!

Great job, glad it worked out.

Thanks Denward!  I appreciate your replies and your nice comments.

ZT (SOHC Apprentice)

[newday777]

I use a cold chisel as a wedge to get between the race and the bottom tree, work around the sides to equally drift the race off.
Or use a dremel with a cutoff blade to cut the race.

[ZTatZAU]

I use a cold chisel as a wedge to get between the race and the bottom tree, work around the sides to equally drift the race off.
...

Yep!  That's exactly how I finished up with mine.

ZT (SOHC Apprentice)

[BenelliSEI]

Curious why you stripped the bearing off a stem you won’t be using?

[ZTatZAU]

BenelliSEI: Curious why you stripped the bearing off a stem you won’t be using?

Curious?  You can't be that curious, John!  But once again... I can't expect you to read, let alone remember, everything I've written here; but you've really been missing a lot of the details in some of my recent posts.   

For a man with your expertise and experience, it must get old plodding through all the same newbie questions and giving the same advice over and over, on topics that have been previously covered ad infinitum, if not ad nauseum.  With that said, I and no doubt many others, do appreciate your patience and taking the time to do so.

To answer your question though, I wanted to remove all the bottom bearing components, without damaging them, in order to accurately measure the stack height of the original bearing set to determine which, if any, of the All Balls shim washers should be used on my new stem.

In hindsight,  I guess I could have removed the bottom race from the frame and made this measurement in place on the old stem, but hey, I'm still learning here and trying to add to my own SOHC experience.

ZT (SOHC Apprentice)

[Floshenbarnical]

PO put tapered bearings in my steering assembly so I don't even have the old races to measure and check his homework.

I'll figure it out.

[BenelliSEI]

You are doing great! Keep it up. J.

[seanbarney41]

The race is not that tight on the stem. Just whack it.

+1, done this dozens of times, have never used heat or freezing.  I use a sharp flat bladed chisel/punch, drive it right into the seal until you can get a piece of the race, then lever or drive it upward.  Only time I ever had trouble, was because the stem was bent/kinked from an accident, at which point your looking for a whole new stem anyway.

[ZTatZAU]

You are doing great! Keep it up. J.

Thanks John!

The race is not that tight on the stem. Just whack it.

+1, done this dozens of times, have never used heat or freezing.  I use a sharp flat bladed chisel/punch, drive it right into the seal until you can get a piece of the race, then lever or drive it upward.  Only time I ever had trouble, was because the stem was bent/kinked from an accident, at which point your looking for a whole new stem anyway.

Thanks Sean!

ZT (SOHC Apprentice)

[scottly]

I wanted to remove all the bottom bearing components, without damaging them, in order to accurately measure the stack height of the original bearing set to determine which, if any, of the All Balls shim washers should be used on my new stem.

You could have simply asked, or read through the tapered bearing thread.
The stock bearing stack is .718" tall. Read post #609 for the rest of your questions:
http://forums.sohc4.net/index.php/topic,1516.600.html

[The Lone Builder]

...
When I did my forks I struggled to find a diagram of what I found inside; then I cam across this in an old issue of Classic Motorcycle Mechanics. Maybe it'll help.

@The Lone Builder, can you provide a link to the entire Classic Motorcycle Mechanics article you mentioned?
Thanks!  ZT

Sorry for the long delay in replying. This was a series of articles.

If you google: project bike honda cb750 site: classicmechanics.com you'll get all the URLs for the series.

If you also search: https://www.classicmechanics.com/show-us-yours-seans-1974-honda-cb750k2/ you'll see a pic of my restored bike, exhibiting the problem with some replacement fork boots - lasted maybe 1,000 kms!

[ZTatZAU]

I wanted to remove all the bottom bearing components, without damaging them, in order to accurately measure the stack height of the original bearing set to determine which, if any, of the All Balls shim washers should be used on my new stem.

You could have simply asked, or read through the tapered bearing thread.
The stock bearing stack is .718" tall. Read post #609 for the rest of your questions:
http://forums.sohc4.net/index.php/topic,1516.600.html

You may have missed post #42 in this thread, wherein I mentioned that I was still working my way through the 26 page tapered bearing thread.  I'm still trying to reconcile some of the incongruent and conflicting information that's been posted there, in order to decide upon the best course of action.

I can't say for sure if I've gotten to the 609th post yet, but I do believe there is a certain benefit to be had from doing somethings for yourself... if only to compare your own results with the results that have been shared by others.  Thanks for sharing yours!

...
When I did my forks I struggled to find a diagram of what I found inside; then I cam across this in an old issue of Classic Motorcycle Mechanics. Maybe it'll help.

@The Lone Builder, can you provide a link to the entire Classic Motorcycle Mechanics article you mentioned?
Thanks!  ZT

Sorry for the long delay in replying. This was a series of articles.

If you google: project bike honda cb750 site: classicmechanics.com you'll get all the URLs for the series.

If you also search: https://www.classicmechanics.com/show-us-yours-seans-1974-honda-cb750k2/ you'll see a pic of my restored bike, exhibiting the problem with some replacement fork boots - lasted maybe 1,000 kms!

Thanks again, Lone Builder!  I appreciate the information and links you've provided.

ZT

[ZTatZAU]

I wanted to remove all the bottom bearing components, without damaging them, in order to accurately measure the stack height of the original bearing set to determine which, if any, of the All Balls shim washers should be used on my new stem.

You could have simply asked, or read through the tapered bearing thread.
The stock bearing stack is .718" tall. Read post #609 for the rest of your questions:
http://forums.sohc4.net/index.php/topic,1516.600.html

Thanks again for your reply Scottly, 

My K1 750's OEM bottom stack measurements were slightly different than yours, but I'm quite satisfied that the All Balls bottom 99-3512 bearing set with the thin 99-1054 washer and seal will work just fine.  The two stack heights were almost identical.

My remaining concern is how the All Balls top bearing set will work out.  I've been distracted with other priorities but did make it through all 26 pages of the Tapered Bearing thread; including your post #609 on page 25.  Despite some conflicting information and opinions on the proper installation order of the All Balls bottom stem components, it's clear to me that the 99-1054 (thin) washer goes on the bottom of the stem, followed by the 33-1007 seal, and then the 99-3512 bearing.

I am still troubled by the reports from some who wound up with an 1/8" or so of extra space between the top bridge and the top fork cover cushions that had to be filled with an O-Ring or some other custom creation. 

In my view, there seems to be no getting around the All Balls top, 99-3511,bearing race sticking out about an 1/8" above the top of the frame's goose neck; which, apparently, results in the extra space described above.  Because of the difficulty in removing the very narrow All Balls races, once installed, I'd like to avoid any surprises when I get to the top of the stem; such as what Scott described in post #609.

...
At the top end, I had a surprise: the top of the inner races I've used before fit neatly inside the nubs on the bottom of the adjuster nut, but the top of the All Balls part is much larger diameter, and the upper washer Must be used. The washer is .078", and the upper seal is another .025", so if too thick of a spacer is used on the bottom, there may not be enough threads on the stem for the adjustment nut to fully engage.

Just to be clear Scott... Did you have enough threads on the top of the stem after assembling the bottom bearing with the thin washer, seal, and tapered roller bearing as you described while still using the All Balls top race, bearing, dust seal and small diameter washer on top?

And if so, (or not), did you wind up with any extra space between the top bridge and the upper fork cover cushion?  OR... Was this all done on your Seely (sic?) frame bike, rather than on a stock CB750, so the extra space above the CB750's fork covers was not a factor at all for your installation?

And if I remember correctly, Steve-O provided a link in the Tapered Bearing thread to another of your posts on the tapered bearing conversion, wherein you advised NOT to use the All Balls top seal or washer.  Was this to make sure there were enough threads showing for the adjuster nut to capture and/or to avoid any extra space between the fork cover cushion and the top bridge?

Sorry for the long read, but I want to be sure of what I'm doing and what the results will be should I go ahead with the All Balls conversion rather than reassembling my front end with the OEM steering stem ball bearing setup.

Thanks for whatever info you (or anyone else) can share and remember!  ZT