Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: McCabe-Thiele (Ted) on December 12, 2021, 01:11:10 PM
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I assembled the front axle today - tightened up the assembly - bearings rotate nicely all looks good except if I rotate the speedometer drive hub it feels as if its binding on the outer chrome ring that bolts on top of the drive plate. My original ring was dented so I have fitted a spare one that looks perfectly round.
I can see that the gap between the speedometer drive hub and the chrome ring is not even it feels as though it is binding.
Any pointers as to the cause I'm suspecting the axle could be slightly bent if that's at all possible - seems unlikely looking at the diameter? Not sure how I could check it myself?
My front spindle has a flat on it to enable tightening of the axle not a hole in the end boss as per DS parts list & parts manual - is this an original fitting?
Update:- I have rotated the drive plate through 180 deg and this seems to have improved the situation substantially - plus I assembled the spindle - nipped it up - then fitted the long bolts that hold the disc - it looks much more central now visually where the chrome ring is close to the speedo drive unit. I guess I need to fit the front wheel to see how it spins in situ.
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Ted, a little unsure of your issue, but am sure it is possible to promote hub binding by mis-instal of the bearings - which only shows up on buttoning up the axle assu. (did you have the bearings out?)
Anyways, a past thread here may be of use?
Cheers.
http://www.sohc.co.uk/index.php/topic,23287.msg209285.html#msg209285
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The binding has now gone after spending some time rotating the chrome cover ring to the best position for a uniform gap except for one bit where it narrows but does not catch. The ring is not damaged the photo just makes it look bad due to focus & shadows. It does not feel as though there is a high spot - not now binding.
First photo the gap is pretty even the when I rotate the speedometer drive position it shows how the gap narrows.
(https://live.staticflickr.com/65535/51750859261_cb5df71366_k.jpg) (https://flic.kr/p/2mR3Fua)gap on drive hub (https://flic.kr/p/2mR3Fua) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Below shows how the gap narrows at one point.
(https://live.staticflickr.com/65535/51750859146_0d3009f32e_k.jpg) (https://flic.kr/p/2mR3Fsb)narrow gap on hub (https://flic.kr/p/2mR3Fsb) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Is this anything to fret about - can't get the gap any more even - I do not want to mess with the chrome ring by trying to shave it down?
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I wonder if the 13mm (?) AF bolt heads are slightly pushing the chrome ring off centre, perhaps a reduced outer diameter washer underneath would allow enough play to allow better centreing?
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I wonder if the 13mm (?) AF bolt heads are slightly pushing the chrome ring off centre, perhaps a reduced outer diameter washer underneath would allow enough play to allow better centreing?
Good shout I have had to use a spanner to keep the hexagon off the ring - worth a try.
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Personally, I wouldn't have used A2 stainless steel for the disc retaining bolts Ted ... from memory they have 30% less tensile strength than 8.8 steel. plus the head size is likely 13mm, which isn't correct
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Personally, I wouldn't have used A2 stainless steel for the disc retaining bolts Ted ... from memory they have 30% less tensile strength than 8.8 steel. plus the head size is likely 13mm, which isn't correct
The SS bolts came with a selection pack - (I'm not a mechanical engineer so please forgive my simplistic view) I considered the tensile strength aspect but disregarded it as I considered there is liitle by way of tensile forces acting on the bolts - the torque setting is not that high (Not sure what it is?) - that the shearing forces from the disc trying to rotate on the hub would not be big enought to shear the bolts. It has not dawned on me until you mention it that the heads are 13 mm not 12 mm like the originals as I had not compared them.
I think that the bigger headed bolts are probably the cause of my centreing problems- I have the old bolts but the heads are pretty corroded so I will replace them. Pleased I have not rushed to fit the front wheel yet! Thanks for the extra pointer about the head size difference Ash.
Update: listed as no longer available at DS & others - I'll have to clean up the originals.
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The Japanese dont work fully to iso standards, in that 8mm bolts have a 13mm hex but they seem to prefer 12mm.
There is another non prefered hex size higher up the range but cant remember which
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Got this from Custom Fasteners website years ago when I was working on the bike.
M10(1.25 pitch) and M12(1.25 pitch) FINE THREAD METRIC BOLTS
For use on Japanese motorcycles and cars. M10(1.25) bolts have a 17mm spanner size, M12(1.25) bolts have a l9mm spanner size. The Japanese often
use a smaller size head on their bolts, so please check there is sufficient clearance for the standard size head we supply, before ordering.
NOTES ON METRIC BOLTS
M4 fits spanner size 7mm. M4 thread pitch is 0.70mm.
M5 fits spanner size 8mm. M5 thread pitch is 0.80mm.
M6 fits spanner size 10mm. M6 thread pitch is 1.00mm.
M7 fits spanner size 11mm. M7 thread pitch is 1.00mm.
M8 fits spanner size 13mm. (Japanese M8 bolts use 12mm spanner size). M8 thread pitch is 1.25mm.
M10 fits spanner size 17mm. M10 thread pitch is 1.50mm.
Cheers
Dennis
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What length are the bolts Ted?
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What length are the bolts Ted?
The bolts are 90 mm long, 12 mm head last 13 or so mm is threaded.
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Shame, the 500 ones are 100mm. I have some of those.
I'll see what I can find Ted, might have something suitable.
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Shame, the 500 ones are 100mm. I have some of those.
I'll see what I can find Ted, might have something suitable.
I'm currently cleaning up the original bolts - its the heads that have pretty light surface rust so should be okay Ken - presently in Evaporust bath.
It's at times like this I wish I had bought a Gateros plating kit.
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I was thinking on this last night Ted.
Couple of suggestions.
The bolt head is 1m wider, so 1/2mm either side, just grind off a small part of the flat nearest the ring, it's a stainless bolt so it wouldn't rust.
Fit the bolt the other way round so the nut is on that side. There are stainless 12mm headed nuts out there, I have some.
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If I'm not mistaken, the standard nuts used have a fairly large captive washer securing the disc. I don't think I would fancy changing any of the spec on such a crucial safety part of the bike. I have the same opinion regarding a previous comment about not worrying too much about the tensile strength of the bolts. If you have to apply the front brake quite hard, and you have fitted good 'grippy' tyres, you only have those 4 bolts transmitting all that force to the bike. Stay with cleaning the originals and fit them the right way round.
Just had a look on eBay and there are some available complete with nuts and the chrome ring, and in the photos look fairly presentable.
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A bit of an update - I've tried the original bolts and it's not an improvement.
Next I'm going to fit a different drive plate as I have one - thought occurs to me that the original rubber centre section might be the cause of pushing things off centre. As I have a spare one that's a no cost option.
Second option is to try a different drive casing / hub unit, last option as it's the most expensive - fit new axle & nut.
Update: I have a drive untit/hub on it's way as insurance - found what might be a reasonable condition one for less than £24 inc postage.
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Yesterday I fitted a used replacement speedometer drive plate & worm drive hub.
This has fixed my chrome ring binding issue - pretty sure it's the drive plate that was the problem. The rubberised centre section I think was causing the issue. The clearance gap between the chrome ring & the hub is much more even so am happy with the outcome.