SOHC.co.uk Forums > CB350/400
My New Project arrives after a 44 year wait!
AndyD:
Feel for you Dave - these things definitely try us!
Have huge sympathy regards the steering head bearings - I've spent far too long messing around with what should be simple replacement and like yourself can't understand how suppliers can simply keep sending out stuff that just isn't right.
I spent yesterday and today replacing the head bearings on the CJ250t as I wasn't happy with the previous tapered roller ones I fitted - they only gave a couple of full turns on the adjuster nut which just felt wrong. I ordered another supposedly correct top bearing which turned out to again be too deep so have now fitted the DSS non-genuine ball bearing version on the top which finally seems to be an exact match to the originals and gives a full 4 turns of the adjuster by hand which feels much better.
My experience has been that the lower bearing in the various replacements are OK but all the top ones sit higher and reduce the available thread for the adjuster.
However even with the 'wrong' bearings on the top the thread for the chrome top nut was still quite generous so I'm wondering what is different on yours / the 400 maybe and that does sound worrying as I guess the main strength of the stem connection is on this nut, especially with the high torque settings mentioned.
Hope you get it sorted.
Cheers,
Andy
Johnny4428:
Think you will be due a bit better fortune after that saga Dave, nice job on the indicator stem earth!😜
K2-K6:
It appears odd to me that the torque instructions are so high (the 750 manual states 58~85 ft/lb) and what it achieves.
Thats a very high figure for such component in either case.
Does the 400 have a pinch bolt on that central top mount too ?
Obviously you don't want the steering moving when in use (twisting around the joint) but much more in clamping etc is from the stanchion clamps top and bottom etc.
Most example of 60 ft/lb range have far more substantial threads and reason to apply such a torque level, rear axle etc.
"Original" taper bearing sets sold by Dresda had one of the bearings modified to allow the correction in height for this scenario. As I understand it, you can't (or couldn't, still looks the same) buy replacement in taper to match the dimensions of original "slim" fit ball race sets. Maybe DD would remember what he had changed (his sets that he had modified) to accommodate this particular dimension.
The std sets are OK, but taper roller really does fit this scenario best for load and durability, so quite desirable if sized correctly. Perhaps more relevant to a higher mileage use as when they were contemporary.
Either type, I'm using black CV molly grease in currently, virtually impervious to water ingress, ideal for high loading and lower angular movement, both types just last longer and much less likely to not damage their track from loading.
This area of setup height is called "stack" dimension in MTB cycle field, with many applications giving consideration to how this is managed in fitment. Likely a modified top bearing is needed here to accommodate switching to taper roller over ball race.
McCabe-Thiele (Ted):
Pyramid do a steering taper roller bearing kit BR 29 for the 400.
In the kit the top bearing is the same size as the original ball bearing part 48.5 x 26 x 15 mm (height).
The bottom bearing is 50 x 30 x 14mm (height) that is 4 mm less than the standard ball bearing at 18 mm
The kit includes 2 x sealing washers.
No issues when using this kit of a shortage of top threads, I think I fitted a 2 mm bottom spacer at the bottom of the column.
I fitted the kit they sell for the 500 - no issues - same kit iirc BR29 - quality bearings in the kit.
K2-K6:
Useful information Ted, as I've said above, they are my preferred design for the load they take.
It is a bit of a pedantic view from me though, just hate "rattling" head stock bearings :) and know if you are chasing them by adjustment it's honestly over for a ball set, especially the lower one. Ordinarily the balls or track are failing if you're chasing it by tightening.
Decent rollers and lubrication never really do that.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version