SOHC.co.uk Forums > CB350/400
Steering Head Bearings
McCabe-Thiele (Ted):
After another search this morning I have found my top outer race I have measured it with my calipers as 48.53 mm now I am confused I get a tad over 48.50 with my micrometer?
Clearly a difference between a 400/4 & a 500 by the looks of it.
Hopefully someone else can clarify the top bearing size for a 400/4 F2 as it might be you can get a taper roller for the top that fits without loosing threads.
The taper upper that I did not fit is a JMT Tapper Roller Bearings Top 26 x 48.5 x 15.75 as I did not want to loose any top threads.
Seabeowner:
Years ago I got a "set" of bearings off Steve with a view to doing my 500 that I've had for 20 years. But the set was missing a bit and to compound it when I took my 500 apart recently it already had tapered bearings installed. I didn't do it, but rebuilt the bike 19 years ago and obviously forgotten! May use bits on a 550.
The bottom bearing is marked H305014. I only have the outer.
https://www.tradebearings.com/h305014-bearing-30-50-14mm-product-84516.html
The top bearing is marked H264815.
https://en.tradebearings.com/N_H264815-170254.html?rel=nobot
AndyD:
Ted,
Interesting - but sad that simply getting replacement bearings is such a pain!
I received the alternative style ones from Wemoto and have had a quick look at these.
The bottom set looks perfect and appears an exact match of the originals, with the exception of the ball bearings being captive.
Top set not so good - the race seems the same but the bearing cage just doesn't fit at all so can't check any further.
Also the top cone is thicker and has a different shape so this may also cause a problem in terms of overall thickness etc. but can't check as the bearings don't fit in.
I've spoken with Wemoto and they are going to look into it - maybe a rogue bearing set but hopefully will find out and update on 'progress'.
Measured up the old bearing and got 48.55 so same as your dimension.
Also measured the overall height of the top assembly and came out at around 14.3mm overall but with only a few BBs fitted - when I get a chance I'll re-check with all bearings in place to see if this is correct or changes much.
Cheers,
Andy
McCabe-Thiele (Ted):
Not doubting your findings Oddjob yours is an early 500 you say - both myself plus Andy have a different size upper ball race - the size variation is too large for it to be a simple measurement error.
Could it be that they changed size during production over the years - this might explain why some folk have so much trouble fitting taper rollers at a later date yet some don't?
Interestingly not all sellers show the same bearings across all the variants wheras some do. My 400F2 was registered in March 1978 so I assume it's a later production version.
McCabe-Thiele (Ted):
Might interest you to know I'm currently looking at converting the original swinging arm to needle bearings instead of the metal sleeves they used back in the 70s. It's about 50% done at the moment with some small machining needed which I'm having to ask a mate to do as I don't have a lathe.
« Last Edit: Today at 05:15:55 PM by Oddjob »
The rear swing arm bearings on my 400 were some sort of plastic sleeve, I've changed them for Brass sleeves (via NJ) - needle rollers sound interesting - similar to the old Mini rear radius arms - they had sleeves on one end that had to be reamed to fit with needle rollers at the other end. Oddly enough the needle rollers usually wore out first due to water ingress. I never understood why they had two such different bearings on the same radius arm shaft.
https://www.ebay.co.uk/itm/174340141835?chn=ps&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=174340141835&targetid=1279902197659&device=c&mktype=pla&googleloc=1006674&poi=&campaignid=12689626702&mkgroupid=124353408922&rlsatarget=pla-1279902197659&abcId=9300529&merchantid=101733956&gclid=CjwKCAjwgviIBhBkEiwA10D2jwz9reN4dmzkpa-vSvbNu-29oJvQwt2Stgebd-2RJ7V7LV60ycqqkRoCmcUQAvD_BwE
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