Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: McCabe-Thiele (Ted) on February 12, 2021, 04:00:04 PM

Title: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 12, 2021, 04:00:04 PM
I am trying to find the diameter of the steering shaft where the lower ball race sits at the bottom yoke.

As my lower race has not yet to be removed not sure if the diameter increases where the bearing sits. The shaft itself measures approximately 26.7 mm in diameter.

The place I am trying to source the taper bearing kit from bearing says the Top Bearing is 48.5mm OD: 26.0 mm ID that's right I think.

He gives the lower bearing as 50.00mm OD:30.0mmID. Unless there is a bigger diameter where the bearing sits I think the OD is too big.

Anyone here know the answer please ?
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: K2-K6 on February 12, 2021, 04:37:43 PM
Someone must have one out to measure for accuracy.

But I "think" they may be something odd like 1 1/8 inch as legacy from english bicycles,  making something like 28.55mm

Needs checking though. The crown race usually flares though to allow you to drop the bearings down the stem and just drift it home for the very last bit.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Deano400 on February 13, 2021, 11:27:40 AM
Ignore the 0.01mm I haven't cleaned it.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: ka-ja on February 13, 2021, 12:25:22 PM
Definately 30mm as already posted.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 13, 2021, 09:17:01 PM
Definately 30mm as already posted.

Thanks ka-ja & Deano400 I'm dropping my steering shaft & yoke at my BiL on Monday so he can remove the bottom race in a Covid secure environment.

I can order my taper roller kit with added confidence.

I have also realised that the correct bottom spacer will mean the steering lock will align properly with the hole in the column.

BiL has reoved the bottom bearing it is 30mm as has been posted. Just need to finalise the spacing and see if the one supplied is about right. Thanks folks. If it helps I will post the link here for the supplier.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 16, 2021, 10:35:57 AM
This is the e-bay online shop second link was how I found them - they had sold out of the cheaper bearings so mine were £30 including postage really helpful - they confirmed the actual bearing sizes too.
I asked if they would fit my model Honda that's when he came back to me with the right ones. They are also bike breakers selling used parts as well as some new stuff.

https://www.ebay.co.uk/str/offshorebikebits?_pgn=4


https://www.ebay.co.uk/itm/Steering-bearings-taper-roller-Honda-CB250-350-400-450-500-550-650-750-super/153984339007?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: AndyD on February 17, 2021, 04:27:33 PM
Ted,
I had problems on the CB400 and also the CJ250T with two different brands of tapered bearings.
The issue seems to be that the upper bearing is simply thicker than the original so reduces available thread on the stem.
Bottom bearing with spacer worked out correctly but top bearing on both caused the problem.
Will be keen to see if the ones you have will work better as it seems crazy that the bearings aren't simply interchangeable without issue.
No other bikes I've worked on have had an issue so guess it's just on some models that things don't fit nicely.
Cheers,
Andy
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 18, 2021, 09:24:58 AM
Ted,
I had problems on the CB400 and also the CJ250T with two different brands of tapered bearings.
The issue seems to be that the upper bearing is simply thicker than the original so reduces available thread on the stem.
Bottom bearing with spacer worked out correctly but top bearing on both caused the problem.
Will be keen to see if the ones you have will work better as it seems crazy that the bearings aren't simply interchangeable without issue.
No other bikes I've worked on have had an issue so guess it's just on some models that things don't fit nicely.
Cheers,
Andy

I'll keep this post updated when the bearing arrive & I have fitted them it will be a few weeks away before I fit them as am doing the frame painting soon /next methinks.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 19, 2021, 05:49:05 AM
Ted,
I had problems on the CB400 and also the CJ250T with two different brands of tapered bearings.
The issue seems to be that the upper bearing is simply thicker than the original so reduces available thread on the stem.
Bottom bearing with spacer worked out correctly but top bearing on both caused the problem.
Will be keen to see if the ones you have will work better as it seems crazy that the bearings aren't simply interchangeable without issue.
No other bikes I've worked on have had an issue so guess it's just on some models that things don't fit nicely.
Cheers,
Andy

Did your bottom spacer replace the existing one under the bottom bearing to allow for the difference in bearing height?
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 19, 2021, 08:54:40 PM
My taper bearing kit arrived today its a German Packaged brand by JMT shown as suitable for Honda CBb 250/350/400/500/550650/75 SSH750 clearly far too universal.

The bearing diameters are the  correct OD & ID  48.6 mm x 26mm for the top bearing: 50 mm x 30 mm for the bottom with a 4 mm spacer.

The Bottom Bearing measures 15.14mm deep: the top bearing 15.70mm deep approx.

What I can't get my head round is that the bottom ball bearing race is approx 13.5 deep. So if the bottom bearing is 15.14 mm deep why does it need a 4 mm spacer as that would raise everything too high as has been mention by others ?

My worst case scenario is I fit the taper roller on the bottom that takes a pounding and put a ball bearing on the top if they do not fit as a pair. A sort of neither fish nor fleash option.

Anyones input / observations welcome.

Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Bryanj on February 20, 2021, 10:49:46 AM
The parts you cant remove are the outer races on the tapers as when fitted there is no "lip" sticking inwards to get a drift on, only way i found was a dremel which, of course, wrecks the race.
You can get the inner races off fairly easily so i would suggest fitting the lower bearing with no shim to start and holding tight into frame to see if anything interfears at frame/yoke ares, on the 500 i used a 1mm shim bought off ebay for not much
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) on February 20, 2021, 08:28:54 PM
If I can find the races off the set I bought in the 80s I'll measure the top race and see how it compares to yours, can't do that with the bottom as Bryan says getting the inner races out is problematic but the top race will come out if you lever it.

No worries I measured my bottom race it was 13.5 mm or thereabouts - I have my top race out I will measure it with the balls in place & post the thickness I get.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Seabeowner on February 21, 2021, 09:23:16 AM

What I can't get my head round is that the bottom ball bearing race is approx 13.5 deep. So if the bottom bearing is 15.14 mm deep why does it need a 4 mm spacer as that would raise everything too high as has been mention by others ?

I think this is because of the different contact points between the two types of bearing. It is higher on the taper bearing so although the overall length (depth) may be about the same the lower yoke will sit in to far without a spacer. Turning the bearing over will give a different result.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: K2-K6 on February 21, 2021, 11:14:16 AM
The original ball set standard equipment cannot be matched as far as I understand,  that's in tapered std manufactured.

Contemporary times for these, suppliers like Dresda had taper sets ground to match the Honda fit and sold as kits.

Referenced by Bryan in this thread  http://forums.sohc4.net/index.php?topic=1516.0 to effectively give a drop in set. 
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: K2-K6 on February 21, 2021, 11:32:39 AM
Some pictures on page 4 of that link show a little more details.

[attachimg=1]

[attachimg=2]

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

Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) 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 -



Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) 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.

(https://live.staticflickr.com/65535/50965488953_09fdd7e882_k.jpg) (https://flic.kr/p/2kDDsfM)Bottom bearings (https://flic.kr/p/2kDDsfM) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) 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.

(https://live.staticflickr.com/65535/50965488488_004de545f1_k.jpg) (https://flic.kr/p/2kDDs7L)Top bearings (https://flic.kr/p/2kDDs7L) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) 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 ?
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Bryanj 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
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Nurse Julie 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.
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) 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 !
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: McCabe-Thiele (Ted) 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
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Bryanj 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
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: Bryanj on February 22, 2021, 12:40:38 PM
If you are worried look at ebay 324462234796
Title: Re: Does anyone know the diameter of the CB400F2 steering shaft at the base?
Post by: K2-K6 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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