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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 10:30 am Post subject: Sb6 steering bearings |
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I wanted to check the bearings, clean them and regreese...
but I can't understand how to take off the lower tree: the upper one went off easily and now I see the naked upper bearing, but I cant push away the lower one..
it seams the upper bearing is screwed onto the steering tube...
any trick? _________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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oily
Joined: 05 Apr 2008 Posts: 4788 Location: worcestershire
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Posted: Sun Nov 04, 2012 11:55 am Post subject: |
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Big hammer
Lets have a picture to explain what you mean Marco _________________ SB6 mk1 (project mega light, big bore)
Sb6 mk2 ( Big Bore)
Sb6 mk2 ( Restored)
Sb6R fighter
Sb6 or Sb7 WANTED |
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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 12:27 pm Post subject: |
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oily wrote: |
Big hammer
Lets have a picture to explain what you mean Marco |
I just came back from my parents home, where the bike is, and I can't take pictures
I^ve removed the upper tree, the upper threaded retaining cover, and I see the double (?) upper bearing and the central pivot pin...
I thought I had to slam down the pivot pin with a rubber hammer to let the bearing free to be removed.. but any attempt (I tried carefully) went bad, so I thad the doubt the upper bearing is threated to the pivot pin...
today I'll take some picture _________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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oily
Joined: 05 Apr 2008 Posts: 4788 Location: worcestershire
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Posted: Sun Nov 04, 2012 12:37 pm Post subject: |
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I see
I repeat....bigger hammer
No, the bearing is not threaded to the pivot pin.
Obviously, you need to protect the threads whilst using a big hammer.
I use a block of wood between the pivot pin and the hammer.
It transpires that the Bimota factory was afraid of grease during the SB6 era.
Which model have you got? Mk1 or Mk2? If Mk1, do NOT damage the bearings as they are unobtainable _________________ SB6 mk1 (project mega light, big bore)
Sb6 mk2 ( Big Bore)
Sb6 mk2 ( Restored)
Sb6R fighter
Sb6 or Sb7 WANTED |
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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 12:46 pm Post subject: |
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oily wrote: |
I see
I repeat....bigger hammer
No, the bearing is not threaded to the pivot pin.
Obviously, you need to protect the threads whilst using a big hammer.
I use a block of wood between the pivot pin and the hammer.
It transpires that the Bimota factory was afraid of grease during the SB6 era.
Which model have you got? Mk1 or Mk2? If Mk1, do NOT damage the bearings as they are unobtainable |
Frame number is 539, but I don't know if MK1 or not
I will not damage the bearings... I've sprayed some WD40 between pin and bearing, this afternoon I will hit stronger...
BTW: the retaining clamp has no way to be torqued as it's flat, It can only be tighteened by hand... and this sound strange to me... but if it works...
many thanks Oily _________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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Evilchicken0
Joined: 12 May 2010 Posts: 2996 Location: London
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Posted: Sun Nov 04, 2012 3:27 pm Post subject: |
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There isn't anything in there to hold it once you taken the torque nut off (with a C or hook spanner). See fi you can take the top bearing out ... I guess you've tried to jiggle it a bit. The top bearing shouldn't be attached to the lower race
If not try hitting it from below on the bottom yoke to lift the top bearing then the bottom yoke should drop free (probably).
You have taken the forks out haven't you _________________ Don't read everything you believe |
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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 5:07 pm Post subject: |
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I tried with a 1.5kg bricklayer hammer and a piece of wood... NOTHING.
it's still tight to the pivot pin with no game.
Tried to heat with an heating gun with the intent to liquify the old grease that could has became glue between pin and bearing... NOTHING. NOT A MOVE
this is the situation:
and this the retaining clamp that has no way to be torqued properly (only by hand i guess):
do you think I have to hit harder or I'm missing something??? _________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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oily
Joined: 05 Apr 2008 Posts: 4788 Location: worcestershire
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Posted: Sun Nov 04, 2012 5:58 pm Post subject: |
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Bigger hammer
Looks like the Mk1 headstock too.
Try not to damage the bearing as they are unobtainable and you will be trying to convert to standard taper bearings instead of the barrel shaped rollers
They are a really tight interference fit and when you finally get the bearing off (with a bigger hammer) it might be worth shaving a few thou off the stem
_________________ SB6 mk1 (project mega light, big bore)
Sb6 mk2 ( Big Bore)
Sb6 mk2 ( Restored)
Sb6R fighter
Sb6 or Sb7 WANTED |
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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 6:07 pm Post subject: |
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oily wrote: |
Bigger hammer
Looks like the Mk1 headstock too.
Try not to damage the bearing as they are unobtainable and you will be trying to convert to standard taper bearings instead of the barrel shaped rollers
They are a really tight interference fit and when you finally get the bearing off (with a bigger hammer) it might be worth shaving a few thou off the stem
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OK, so next time a little more anger even if I hope that hits won't ruin the race
but if it is fitted with this interference (I avoid to ask "why", as we are talking about a Bimota) how will I retight?
I admitt that the temptation to leave them in place is becoming big
Heat gun could help? _________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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Evilchicken0
Joined: 12 May 2010 Posts: 2996 Location: London
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Posted: Sun Nov 04, 2012 6:11 pm Post subject: |
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Use some carb cleaner to dissolve the grease on the stem and then some penetrating oil _________________ Don't read everything you believe |
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oily
Joined: 05 Apr 2008 Posts: 4788 Location: worcestershire
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Posted: Sun Nov 04, 2012 6:17 pm Post subject: |
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Heat would certainly help but on the bearing not the stem.
Yes you right, they are far too tight with or without grease. I assure you it is not the grease holding it together but the interference fit
Bigger hammer _________________ SB6 mk1 (project mega light, big bore)
Sb6 mk2 ( Big Bore)
Sb6 mk2 ( Restored)
Sb6R fighter
Sb6 or Sb7 WANTED |
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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 8:32 pm Post subject: |
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THANK YOU!!!
Done!
hit with no fear and the lower stem went down. Cleaned,
checked for scratches and regreased. Remounted heating the upper race to decrease interference.
I think I'll tighteen a little bit with a tool I used to fit the headraces in the Honda fours... a 8mm rod with flat faces to be compressed: using a proper brass spacer I would have to fit it right:
I think I'll check even the swingarm pivot as it seems in Bimota were saving on grease... _________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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oily
Joined: 05 Apr 2008 Posts: 4788 Location: worcestershire
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Posted: Sun Nov 04, 2012 8:35 pm Post subject: |
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The solution to all the worlds problems......
A bigger hammer
Well done, you now know why the adjustment only needs to be hand tight _________________ SB6 mk1 (project mega light, big bore)
Sb6 mk2 ( Big Bore)
Sb6 mk2 ( Restored)
Sb6R fighter
Sb6 or Sb7 WANTED |
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Mako
Joined: 17 Dec 2011 Posts: 141 Location: Reggio Emilia, Italy
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Posted: Sun Nov 04, 2012 8:45 pm Post subject: |
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oily wrote: |
The solution to all the worlds problems......
A bigger hammer
Well done, you now know why the adjustment only needs to be hand tight |
_________________ Honda CB450K1 - CB750K2 - CB500K1 - RC30 - Ducati 750SS - Bimota SB6 |
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