Author Topic: Does anyone know the diameter of the CB400F2 steering shaft at the base?  (Read 576 times)

Offline K2-K6

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #15 on: February 21, 2021, 11:32:39 AM »
Some pictures on page 4 of that link show a little more details.

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The original "stack" height has a seal washer for the bottom race which the new kit may not have.


Offline Macabethiele (Ted)

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #16 on: February 21, 2021, 02:18:24 PM »
Reading the 2005 link it does not appear to be about the CB400 but a CB550.
Putting  that aside what is interesting is that the taper bearing measurements quoted appear to be as follows:

     Top 26 x 48.5 x 15.2            mine are 26 x 48.5 x 15.70 so a little taller. Original ball bearings Top 26 x 48.5 x 14.0 approx.
Bottom 30 x 50.0 x 14.4            mine are 30 x 50.0 x 15.14 so a little taller. Original ball bearings Bottom 30 x 50 x 17.8 approx

I guess they are just a different kit to mine hence the hight differences.

My old Top Ballrace measured about 13.5-14 mm: Bottom Ballrace measures 17.55-17.60 with calipers. I need to double check this but this explains why they sent a 4 mm spacer but that ought to be nearer 2.54 mm. Original bottom yoke spacer is 0.95 mm.

I guess what I need to do is get the outer bearing races fitted  into the frame and look at it then -



« Last Edit: February 21, 2021, 08:15:14 PM by Macabethiele (Ted) »
Honda CB400F2 under restoration
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Offline Macabethiele (Ted)

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #17 on: February 21, 2021, 03:36:16 PM »
This is my bottom bearings visual comparison - I guess it will need some spacing but 4 mm is way too much.

Bottom bearings by Macabe Thiele, on Flickr
Honda CB400F2 under restoration
Jeep Grand Cherokee WJ
Jeep Grand Cherokee WK
Mercedes R129 SL500

Offline Macabethiele (Ted)

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #18 on: February 21, 2021, 03:40:02 PM »
This is my top bearing the roller replacement is in the range of 1.7 -2.2 mm taller than the ball bearing type.

Top bearings by Macabe Thiele, on Flickr
Honda CB400F2 under restoration
Jeep Grand Cherokee WJ
Jeep Grand Cherokee WK
Mercedes R129 SL500

Offline Macabethiele (Ted)

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #19 on: February 22, 2021, 11:05:59 AM »
Sorry about asking this question again in another way it would be completely unnecessary had I taken more photos as I was dismantling the steering and taking off the forks. I was in such a rush to strip it down & tbh the idea of fitting taper rollers was not on my mind.

I have it in my brain that when I removed the top yoke that there was a fair bit of thread section above the addjustment nut. Reading about taper roller conversion posts seems to mention a thread shortage issue or even fouling at the bottom if the spacing is not right on the lower bearing.

Having established that my lower bearing is not as tall as the original ball bearing am wondering if my existing 0.95mm washer will work rather than making up the whole difference in bearing thickness with a spacer. Just not sure what difference 1.7mm loss of bearing depth will make.

If I manage to source 2.5 mm spacer to replace the original 0.95 mm this would be close to the original at the bottom but I still have the problem of the top bearing height being 1.7 mm taller, so is there enough thread on the adjuster to not have to worry about it ?
Still leaves me with the fall back position of putting a ball race at the top provided the two styles are compatable.

Lastly of course there is the steering lock engagement to consider - am I overthiking this & boring everyone ?
« Last Edit: February 22, 2021, 11:36:50 AM by Macabethiele (Ted) »
Honda CB400F2 under restoration
Jeep Grand Cherokee WJ
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Mercedes R129 SL500

Offline Bryanj

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #20 on: February 22, 2021, 11:38:52 AM »
Try it with the shim you have, the inner race normaly comes back off easy if you need to add more.
If the shim is too small the lower yoke binds on the frame.
For shims i just put 1mm shim 30mm id into ebay

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #21 on: February 22, 2021, 11:42:44 AM »
Hopefully you can understand now why Graham never fits these type of bearing, they are an absolute pain and just stick up too high. He did try on his 550 Mongrel he's recently built but gave up and went back to original type. It would have worked if he had milled down the internal lip by about 5mm but he would have had to strip the bike down completely to do it and you can't get a whole frame in the milling machine anyway.
« Last Edit: February 22, 2021, 12:00:17 PM by Nurse Julie »
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Macabethiele (Ted)

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #22 on: February 22, 2021, 12:07:52 PM »
Try it with the shim you have, the inner race normaly comes back off easy if you need to add more.
If the shim is too small the lower yoke binds on the frame.
For shims i just put 1mm shim 30mm id into ebay

That ebay search worked a treat seems JCB buckets use them !
Honda CB400F2 under restoration
Jeep Grand Cherokee WJ
Jeep Grand Cherokee WK
Mercedes R129 SL500

Offline Macabethiele (Ted)

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #23 on: February 22, 2021, 12:12:22 PM »
Hopefully you can understand now why Graham never fits these type of bearing, they are an absolute pain and just stick up too high. He did try on his 550 Mongrel he's recently built but gave up and went back to original type. It would have worked if he had milled down the internal lip by about 5mm but he would have had to strip the bike down completely to do it and you can't get a whole frame in the milling machine anyway.

NJ not the words I wanted to hear but my least desirable  "Mongrel" option of mixed bearing types looks theoretically possible does it not? 

Please say yes that the mixed bearing option is an option albeit neither Flesh nor Fish.lol
Honda CB400F2 under restoration
Jeep Grand Cherokee WJ
Jeep Grand Cherokee WK
Mercedes R129 SL500

Offline Bryanj

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #24 on: February 22, 2021, 12:30:21 PM »
As long as the yokes turn freely and have no play whatever works is good, i have long said that tapers are not necessarily any better as they still "pit" and get notchy.
When rotating as designed they last an incredible legth of time but just moving back and forth a few degrees with over 90% of the time in one place i dont think so

Offline Bryanj

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #25 on: February 22, 2021, 12:40:38 PM »
If you are worried look at ebay 324462234796

Offline K2-K6

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Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
« Reply #26 on: February 22, 2021, 12:56:50 PM »
"Please say yes that the mixed bearing option is an option albeit neither Flesh nor Fish.lol"

Nothing wrong with this at all from a technical point of view.  Quite common to mix bearing types according to load demand.

The taper is most beneficial on the bottom in absolute terms,  top just really keeps it from wobbling or falling out  :)

You get similar in MTB cycles with a complete mess of different frame, fork and bearing size. They don't have a fixed length stem though, so can be made up with all sorts of different components to fit various types of forks etc.

 

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