SOHC.co.uk Forums > CB350/400
My New Project arrives after a 44 year wait!
Laverda Dave:
You have raised some interesting points Nigel.
There is no pinch bolt on the top collar although there are two pinch bolts on the top yoke to camp on the fork tubes. Ash checked the torque figure and it is correct but I really fail to understand why it is so high and has such a wide range of between 57-86Ibs? The castellated nut fitted below the top yoke is what preloads the bearings but that doesn’t have a torque figure and instead relies on ‘feel’ to secure the bearings to make sure they don’t bind and to eliminate undue free play. From what I can see the yoke centre nut (centre steering nut) is there to hold the top yoke firmly in position, the two pinch bolts with an 8lb torque setting actually hold the fork legs in position along with the two lower yoke bolts.
The stepped taper bearing as fitted by DD, I remember this kit back in the day, I also remember how expensive it was and there were much cheaper alternatives but of course the reason was because they didn’t have the stepped bearing!
This brings me on to another point, Ted; it was the Pyramid kit I purchased after reading the posts on the forum about fitting taper kits. The kit supplied by Pyramid was the BR29 kit and it didn’t fit! I only got one turn on the centre nut when fully torqued home (and this I consider is what damaged the thread of the steering stem). In my view this was very dangerous. I contacted Pyramid to advise them. They asked me to send photos and measurements of the fitted parts and this is what I did along with an explanation of how I fitted the kit.
The photos I sent to Pyramid are attached to this post. You can see how the top bearing race protruded 1.25mm from the steering head even drifted fully home. When the top bearing is fitted to the race it protruded by 6.5mm and this is what used up all the available thread for the centre nut. Nick Walker form Pyramid agreed with my findings and this is when he advised they would look at fitting a stepped bearing (as DD offered back in the day so the issue with fitting these kits was known about back then).
I offered to be a guinea pig to try the new stepped bearing arrangement Pyramid were proposing to use but I received a response back they were contracting the ‘restorers of these bikes’? Has anyone on the forum been contacted by Pyramid to try the new stepped bearing considering most of the people who restore these bikes are likely to be forum members?
I checked the Pyramid Parts site yesterday and they are still selling the BR29 kit with no mention of a stepped bearing being supplied with the kit itself being a generic fit across a range of Honda bikes! This issue doesn’t just appear to apply to the 400/4 other people with other bikes (Magpie, VFR, Andy D, CJ250 and others) are having problems with these kits, fact is the suppliers appear to be nothing more than box shifters, they don’t appear to be doing any research of their own when a problem has been identified by the people trying to fit these kits.
I contacted Steve at 400bits yesterday to order the steering stem he has in stock and I found out a bit more information. Steve mentioned the stem he has is 209mm in length but some stems he has sold are longer so I needed to check my stem prior to ordering. On checking I found my stem measures 219mm!
I checked the parts list and found there are two lower yokes listed for the UK model. Part number 53200-377-610B for bikes up to serial numbers 1066198 for the F and 1078879 for the F2. It then changed to Part Number 53200-377-611B from 1066199 for the F and 107880 for the F2. There is no description given for the change but I assume the earlier part number relates to the 219mm steering stem and the later to the 209mm steering stem as my bike frame number is 1074127 and is a 1977 F2. Despite the 219mm stem I have fact is the taper bearing kit didn’t fit and that why I had to install the hybrid arrangement of taper lower and caged bearing upper.
The upshot is my rebuild has stalled because I cannot locate another lower yoke, the one Steve has is too short. I contact someone else yesterday who is advertising a yoke on ebay but it doesn’t look in very good condition and I think it maybe a 350four item. He’s going to check it tomorrow, fingers crossed!
Anyway, I'm off out for a ride on my RE Interceptor whilst the sun sometimes shines 8)
McCabe-Thiele (Ted):
I bought the Pyramid kit as a member here I think it was "oldchuffer" fitted the kit without any thread issues on his 400, the same kit fitted my 500.
As the top bearing heights for the plain & the taper kit are the same it's annoying that you had issues - I did wonder if there were different shaped top washer/cups- then again others have had problems fitting taper roller kits to the 400.
Logic would sort of dictate that the taller column might be better - that said if the distance between the tube base and the threaded section is the same then the extra height would it not just raise the top fork bracket height?
As it happens my 400 is a mongrel arrangement with a taper roller in the bottom (not Pyramid part & taller than theirs) with a plain bearing in the top (with the plastic ball spacers) due to the height issue you had.
I did wonder if Pyramid have changed the top bearing design so the bearing sits differently - was your experience recent Dave?
Laverda Dave:
A bit more progress to report during the past week. I managed to obtain another lower steering stem from Steve at 400four bits. I collected it on Tuesday from the powder coater.
Yesterday I summoned up some enthusiasm and stripped down the front end to remove the damaged lower yoke. When I compared the new and the old side by side I noticed the ‘original’ lower yoke doesn’t have the steering lock cut out in the stem! The original yoke is also a lot thicker at the base.
I carefully removed the taper bearing, 3mm washer and dust seal and fitted these to the new yoke. Straight away I could see there wasn’t enough thread showing so I took it apart and left the 3mm washer off. Doing this caused the yoke to rub on the frame so I carefully machined the 3mm washer down to 1mm and it worked. I still only have two complete turns of the centre steering nut which still isn’t good imo and I will torque the nut up in stages from 30lb.
Today I will be refitting the front end and hopefully going forwards rather than backwards with this build!
McCabe-Thiele (Ted):
That's odd - no hole for the steering lock Dave?
That said the only time I used my steering lock on my Honda 250 Dream back in the 1960s when I returned to my bike it would not unlock. I had to go out and buy some Plus Gas as the key stuck solid. I've never used a bike steering lock since.
K2-K6:
Progress at least Dave. I'd still be suspicious of that book specification torque figure on limited threads though. Essentially the steering is directly linked through the base triple to stanchion, just how much location the maximum torque could apply, along with its effect (through friction in its faces) I'm not sure.
Have you considered making a new stem for hhe damaged one, turning the factory weld off the base, inserting and welding the new item in situ ?
You could make a longer one to accommodate the new bearings etc.
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