Tapered bearing installation and the rubber seal
- OKC_Kent
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Tapered bearing installation and the rubber seal
31 Jan 2006 07:47
I took the front end down Saturday to install tapered neck bearings. When taking the bottom bearing off there was a rubber seal beneath it, I guess to protect the original bearings from the elements.
Should I have re-installed that rubber seal? It got pretty demolished during removal of the bearing, and now that I have the whole deal back together I'm having second thoughts.
Should I have re-installed that rubber seal? It got pretty demolished during removal of the bearing, and now that I have the whole deal back together I'm having second thoughts.

Cashion, OK
78 KZ650 B2 85,000+ miles
78 KZ650 B2 85,000+ miles
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- Biquetoast
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- King Jeremy The Wicked
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Re: Tapered bearing installation and the rubber seal
31 Jan 2006 08:22
That's funny. I just did the same thing.
I stared at the box from the bearings a while, re-reading it. It said to remove the seal, but it never said to re-install it.
I actually tried to put it back in... twice... above and below the bottom washer (which, arguably, also should not be there with the new bearings)...
...just to ease your mind, it cannot work. There is nothing to allow the rubber seal to stay in position on its own, nor hold it there. It just gets completely squished no matter how you try to put is back together, and then binds against the headstock pointlessly.
Feel better?
I stared at the box from the bearings a while, re-reading it. It said to remove the seal, but it never said to re-install it.
I actually tried to put it back in... twice... above and below the bottom washer (which, arguably, also should not be there with the new bearings)...
...just to ease your mind, it cannot work. There is nothing to allow the rubber seal to stay in position on its own, nor hold it there. It just gets completely squished no matter how you try to put is back together, and then binds against the headstock pointlessly.
Feel better?

(1.) '75/'76 KZ400D - Commuter
(2.) '78 KZ750B3 Twin - Commuter
(3.) '78 KZ750B3 Twin - Commuter
(4.) '75 KZ400D - Sold
kz750twins.com
(2.) '78 KZ750B3 Twin - Commuter
(3.) '78 KZ750B3 Twin - Commuter
(4.) '75 KZ400D - Sold
kz750twins.com
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- OKC_Kent
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Re: Tapered bearing installation and the rubber seal
31 Jan 2006 09:16
OK COOL.
What I did was seat the lower bearing, installed both races in the top and bottom, greased the heck out of them and put it all back together. I snugged the nut to let the forks flop to the side under their own weight. I still need to get a 1-1/16" socket to torque that top stem nut but all seems good.
I was looking at the old races, they were cratered and dimpled. Maybe in her previous life she was a wheelie king?:silly:
What I did was seat the lower bearing, installed both races in the top and bottom, greased the heck out of them and put it all back together. I snugged the nut to let the forks flop to the side under their own weight. I still need to get a 1-1/16" socket to torque that top stem nut but all seems good.
I was looking at the old races, they were cratered and dimpled. Maybe in her previous life she was a wheelie king?:silly:
Cashion, OK
78 KZ650 B2 85,000+ miles
78 KZ650 B2 85,000+ miles
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Re: Tapered bearing installation and the rubber seal
31 Jan 2006 10:01
OKC_Kent wrote:
Boy, mine were too. The old grease was now hardened lumps of nearly rock, stuck between the bearings. Once I got all the weight off the forks/trees and just before I got the bearings (I was doing a front-end teardown anyway), I could finally feel how ratchety the steering was. Wow. So much better now....
...I was looking at the old races, they were cratered and dimpled....
Boy, mine were too. The old grease was now hardened lumps of nearly rock, stuck between the bearings. Once I got all the weight off the forks/trees and just before I got the bearings (I was doing a front-end teardown anyway), I could finally feel how ratchety the steering was. Wow. So much better now....
(1.) '75/'76 KZ400D - Commuter
(2.) '78 KZ750B3 Twin - Commuter
(3.) '78 KZ750B3 Twin - Commuter
(4.) '75 KZ400D - Sold
kz750twins.com
(2.) '78 KZ750B3 Twin - Commuter
(3.) '78 KZ750B3 Twin - Commuter
(4.) '75 KZ400D - Sold
kz750twins.com
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- RonKZ650
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Re: Tapered bearing installation and the rubber seal
31 Jan 2006 10:05
Every set of the stock balls and races will be dimpled, doesn't matter if it was only ridden by a 75 yr old grandma to church on Sunday. Reason is first pothole the motorcycle ever hit on day one dimpled the bearing races and the dimpling continues to progress every pothole from there on out. You'll notice the dimpling will always cause your handlebars to center pointing the front end straight ahead on any of these bikes with dimpled races, because the wheel is always straight ahead when the dimpling happens. Just to be the strange guy I admittedly am, I changed to tapered rollers in all my Kawasakis 15 or 20 yrs ago and could never actually tell one ioda of difference, so now I ride the last remaining ratty KZ650 with the dimpled races.
OKC_Kent wrote:
OKC_Kent wrote:
OK COOL.
What I did was seat the lower bearing, installed both races in the top and bottom, greased the heck out of them and put it all back together. I snugged the nut to let the forks flop to the side under their own weight. I still need to get a 1-1/16" socket to torque that top stem nut but all seems good.
I was looking at the old races, they were cratered and dimpled. Maybe in her previous life she was a wheelie king?:silly:
321,000 miles on KZ's that I can remember. Not going to see any more.
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- OKC_Kent
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Re: Tapered bearing installation and the rubber seal
31 Jan 2006 10:51
Are your bikes with the 15 yr tapers still smooth, with no ratchety feel?
Cashion, OK
78 KZ650 B2 85,000+ miles
78 KZ650 B2 85,000+ miles
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- RonKZ650
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Re: Tapered bearing installation and the rubber seal
31 Jan 2006 11:57
OKC_Kent wrote:
As far as I can tell, yes, but like I said the ratchety thing doesn't bother me.
Are your bikes with the 15 yr tapers still smooth, with no ratchety feel?
As far as I can tell, yes, but like I said the ratchety thing doesn't bother me.
321,000 miles on KZ's that I can remember. Not going to see any more.
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- pjx
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Re: Tapered bearing installation and the rubber seal
28 Aug 2006 15:34
Ok this is really cool. I just bought a KZ550 off godjester and he says I need to do this. So where do I find the right one for my 1980 kz550? Because rith now the garage has parts all over and I need to start putting it back together.
Paul
Paul
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- OKC_Kent
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Re: Tapered bearing installation and the rubber seal
28 Aug 2006 17:40
Gotta love a bike rebuild project! Get your bearings from Jeff at
www.z1enterprises.com
and then throw a few pictures up.
Cashion, OK
78 KZ650 B2 85,000+ miles
78 KZ650 B2 85,000+ miles
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- godsjester71
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Re: Tapered bearing installation and the rubber seal
28 Aug 2006 18:03
OKC_Kent wrote:
Shouda sold it t someone i don't know. :woohoo: :woohoo: :woohoo:
Cool, I found it for you here:
www.z1enterprises.com/detail.aspx?ID=216
Post edited by: godsjester71, at: 2006/08/28 21:19
Gotta love a bike rebuild project! Get your bearings from Jeff at www.z1enterprises.com and then throw a few pictures up.
Shouda sold it t someone i don't know. :woohoo: :woohoo: :woohoo:
Cool, I found it for you here:
www.z1enterprises.com/detail.aspx?ID=216
Post edited by: godsjester71, at: 2006/08/28 21:19
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- loudhvx
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Re: Tapered bearing installation and the rubber seal
29 Aug 2006 00:13
It must make a difference on really bad dimples. When I converted to taper-rollers, it solved the really annoying problem of being wiggly on non-flat roads while braking.
If the center of the road forms a hump(or the car tire-tracks form shallow canyons) like we have in Chicago, you have to correct the steering slighty if you are riding on the slanted transition between hump and canyon because you are on a slight slant. Because the bars are not straight ahead, when you hit the brakes, the bearings try to center in the dimples which causes the bars to alter their course. The harder you brake, the more it alters course. It's not severe, but it gives an un-settling feeling like the tires are slipping or something. It's most noticeable at intersections where the humps are at their most severe.
My bearings were really bad so the taper bearings made a big difference in eliminating this behavior.
If the center of the road forms a hump(or the car tire-tracks form shallow canyons) like we have in Chicago, you have to correct the steering slighty if you are riding on the slanted transition between hump and canyon because you are on a slight slant. Because the bars are not straight ahead, when you hit the brakes, the bearings try to center in the dimples which causes the bars to alter their course. The harder you brake, the more it alters course. It's not severe, but it gives an un-settling feeling like the tires are slipping or something. It's most noticeable at intersections where the humps are at their most severe.
My bearings were really bad so the taper bearings made a big difference in eliminating this behavior.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
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Kz550 valve train warning.
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- timber
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Re: Tapered bearing installation and the rubber seal
29 Aug 2006 20:46
i just switched mine out last night. mine still had the ball bearings in. i put the bigger seal on the lower and the smaller one on top. they fit fine and i was able to get everything back together ok. or did i do something wrong :lol:
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