Author Topic: Stubborn SOB  (Read 1966 times)

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Offline knowsnothing

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Stubborn SOB
« on: July 29, 2010, 09:09:22 am »
Hey All.  I am trying to replace the wheel bearings on my bike (k8).  I got the backs out without too much trouble, but the front is being a real prick.  I can't get the speedo drive gear off to have at the front ones.  I know what i need to do (spin off #16 from #1) , but i can't get a good enough grip on #1 to separate them.  I have already marred it with the vice grips.  Any tips/tricks/tools that help??



Here is the offending wheel:





1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces

Offline CB750Ken8

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Re: Stubborn SOB
« Reply #1 on: July 29, 2010, 09:28:49 am »
I had the same problem, soak 16 in PB Blaster really soak it! Then grab your nearest 11/16 or 19/32 i can't remember which one fits it properly place 11/16 wrench up against something to hold it in place while its around #1s flat spot, it will require a LOT of force to loosen this then get yourself a wrench that will fit over 16 and crank, the worst that will happen is you'll bust your 11/16 wrench. That's how I had to get mine off.
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Offline gmonkey

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Re: Stubborn SOB
« Reply #2 on: July 29, 2010, 09:31:09 am »
And here I looked at the topic and thought you had a personal message for me...

Why vice grips can you not get a wrench or socket on the hex portion?  You could rent an electric impact wrench at a hardware store.
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Offline knowsnothing

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Re: Stubborn SOB
« Reply #3 on: July 29, 2010, 09:51:05 am »
Hey Ken, thanks for the tip.  I started soaking last night and will let if go a few more days i guess.  I guess its time to hit the gym or something. 

GMonkey - the vice it for #1,  it is round with 2 flat sides.  I didn't have anything that would fit in the slot to i tried to vice it.  The other side, #16, i had a hex on. 
1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces

Offline MCRider

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Re: Stubborn SOB
« Reply #4 on: July 29, 2010, 10:28:13 am »
Hey Ken, thanks for the tip.  I started soaking last night and will let if go a few more days i guess.  I guess its time to hit the gym or something.  

GMonkey - the vice it for #1,  it is round with 2 flat sides.  I didn't have anything that would fit in the slot to i tried to vice it.  The other side, #16, i had a hex on.  
I thought the butt end of the axle had a hole in it? For sticking a rod in?

Maybe you could drill a hole in it, put a punch thru it then put the whole thing in a vice.

How about clamping the butt end back in the fork leg to hold it?

Good luck.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
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Offline knowsnothing

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Re: Stubborn SOB
« Reply #5 on: July 29, 2010, 11:12:58 am »
I thought the butt end of the axle had a hole in it? For sticking a rod in?

Maybe you could drill a hole in it, put a punch thru it then put the whole thing in a vice.

How about clamping the butt end back in the fork leg to hold it?

Good luck.

Hey MC,

Yeah, in all of the books i have, they show a hole in the end, but mine definitely does not have one.  I attributed it to that fact it is a K8 and not an earlier bike.  If i were to drill a hole in the end, do i have to worry about it affecting anything?
1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces

Offline MCRider

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Re: Stubborn SOB
« Reply #6 on: July 29, 2010, 11:20:58 am »
I thought the butt end of the axle had a hole in it? For sticking a rod in?

Maybe you could drill a hole in it, put a punch thru it then put the whole thing in a vice.

How about clamping the butt end back in the fork leg to hold it?

Good luck.

Hey MC,

Yeah, in all of the books i have, they show a hole in the end, but mine definitely does not have one.  I attributed it to that fact it is a K8 and not an earlier bike.  If i were to drill a hole in the end, do i have to worry about it affecting anything?
Wow that's weird (to me) and inconvenient to you.

I don't think it would hurt. Wouldn't have to be a real big hole like the earlier OEMs. Just something big enough to stick a punch or rod into to make a "T". Then put the T in the vice and you should be good. Soaking and all the rest as well.

But hey, it ain't my axle.  ;)
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline mrrch

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Re: Stubborn SOB
« Reply #7 on: July 29, 2010, 11:25:08 am »
Use FIRE, maybe a heat gun would be safer to heat up the nut :)
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Offline knowsnothing

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Re: Stubborn SOB
« Reply #8 on: July 29, 2010, 01:19:56 pm »
Dont worry mrrch, I am going to rough this thing up this weekend, fire, ice, earth, sky, water! Everyone start searching their extras bins now.....it could get ugly.
1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces

Offline MCRider

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Re: Stubborn SOB
« Reply #9 on: July 29, 2010, 02:44:58 pm »
Dont worry mrrch, I am going to rough this thing up this weekend, fire, ice, earth, sky, water! Everyone start searching their extras bins now.....it could get ugly.
I looked on eBay to see about the hole/no hole dichotomy. Sure enough the 78s didn't have them. Saving money on production? Anyway, there were 78s on sale and if they are the same dimensions you could replace with earlier, which were for sale too. And I have 2 earler ones myself.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline TwoTired

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Re: Stubborn SOB
« Reply #10 on: July 29, 2010, 03:02:43 pm »
The side with the hex on it is where the BF wrench goes.  The other end gets clamped in the fork tube end to hold it in place.  Then twist the hex.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

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Offline MRieck

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Re: Stubborn SOB
« Reply #11 on: July 29, 2010, 06:15:25 pm »
The side with the hex on it is where the BF wrench goes.  The other end gets clamped in the fork tube end to hold it in place.  Then twist the hex.

Cheers,
The smart way of doing it. Heat doesn't hurt either. I just replaced the wheel bearings for andyCB750 and that axle had 2 ounces of Loctite on the hex. Some Mapp and a breaker bar got it apart. use NeverSeize on the axle when putting it together.
« Last Edit: July 29, 2010, 06:17:01 pm by MRieck »
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Offline Don R

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Re: Stubborn SOB
« Reply #12 on: July 29, 2010, 09:58:20 pm »
Heat, that's what did mine.
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Offline scottly

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Re: Stubborn SOB
« Reply #13 on: July 29, 2010, 10:09:58 pm »
My K1 had the hole, my K7 has the flats. Grind off the sides of an open end wrench until it fits onto the flats. If you do have to resort to brute force, make sure you file any raised metal down, so the axle sits flat in the fork tube cradle and clamp.
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Offline OldSchool_IsCool

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Re: Stubborn SOB
« Reply #14 on: July 30, 2010, 03:11:47 am »
Or do as TT suggested and clamp the side with the flats back into the fork.  Maybe get a BF adjustable wrench to get on the flats.
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Offline knowsnothing

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Re: Stubborn SOB
« Reply #15 on: July 30, 2010, 07:48:56 am »
thanks for all of the advice, one of those is bound to work.  

Quick question (and excuse my ignorance): When you say re-attach flat side to fork, should the fork still be on the bike or am i just using it as an anchor?  If it is still attached to the bike, should i take the other fork off or just leave it un-clamped or loosely clamped? (don't want to bend or tweak anything)

« Last Edit: July 30, 2010, 07:53:35 am by knowsnothing »
1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces

Offline TwoTired

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Re: Stubborn SOB
« Reply #16 on: July 30, 2010, 09:58:17 am »
You're essentially using the fork tube as another BF wrench for the "flat" side.  I wouldn't think on or off the bike matters much.   But, I've yet to encounter one that was on so tight as to bend fork tubes.  That would be scary.   Anyway you are using the fork tube as the opposing wrench.  You should have one hand on the tube and the other on the wrench.  That way, minimal force is applied to the fork tube.  The wrenches are arranged like the end of a scissors, where you either pull them apart or force them closed.

My MC shop friend puts the hex side in the bench vise and uses a big pipe wrench on the other end.   But, I don't like the marks the pipe jaws leave on the part which have to be hammered/filed smooth again.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline knowsnothing

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Re: Stubborn SOB
« Reply #17 on: July 30, 2010, 10:14:08 am »
Thanks TT, i will give it a go tonight. 
1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces

Offline knowsnothing

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Re: Stubborn SOB
« Reply #18 on: August 04, 2010, 07:07:11 am »
I listened to all of your sage advice and used the fork and BF wrench and made that nut my b*tch.  One step closer.....thanks again!
1978 CB750k Green - 811 engine
1978 CB750k Blue - for sale
1974 CB375F Faded Black - had to have that 6th gear
1976 CB400F Red - in many pieces
1973 CB350F TBD - in many pieces