Speedometer gear box disassemblySpeedometer gear box disassemblyI have most of the speedometer gear box disassembled, but can't figure out how to remove the brass parts with the internal gear. Any tips?
Speedometer gearbox disassemblyHi I have just joined the forum and am based in Leeds UK currently restoring 1964 CB72 and 1964 CB77 Was planning proper intro and restoration thread but saw your query and have recently dealt with same problem myself as one of my speedometer gearboxes was seized and I had to work out how to take it apart as parts diagrams I have don't show gearbox inards. If you look at the gearbox from the inside you need to lever out the oil seal, there is then a fiddly circlip to remove which overlies a washer holding the ring gear in place. Behind the ring gear are two shims. From your post sounds like you have got this far. The brass end to the lower part of the gearbox is secured by a small brass grub screw which is situated on the lower surface. When this has been removed the brass end cap can be removed from the gearbox either by gripping the end careful in a vice and puliing and twisting or if it's to tight by hitting the opposite cable drive end with a small punch which will drift it out. The brass end cap has a serrated margin and is a simple press fit in the gearbox end when removed there is a washer and then the worm drive to the cable which runs in the inner end of the brass fitting. There is a further washer between the worm drive / cable attachment and the gearbox body.I have photos of disassembled gearbox which I will try to upload if this post is OK. Hope this helps. PhilD.
Speedometer gearbox disassemblyHi I have just joined the forum and am based in Leeds UK currently restoring 1964 CB72 and 1964 CB77 Was planning proper intro and restoration thread but saw your query and have recently dealt with same problem myself as one of my speedometer gearboxes was seized and I had to work out how to take it apart as parts diagrams I have don't show gearbox inards. If you look at the gearbox from the inside you need to lever out the oil seal, there is then a fiddly circlip to remove which overlies a washer holding the ring gear in place. Behind the ring gear are two shims. From your post sounds like you have got this far. The brass end to the lower part of the gearbox is secured by a small brass grub screw which is situated on the lower surface. When this has been removed the brass end cap can be removed from the gearbox either by gripping the end careful in a vice and puliing and twisting or if it's to tight by hitting the opposite cable drive end with a small punch which will drift it out. The brass end cap has a serrated margin and is a simple press fit in the gearbox end when removed there is a washer and then the worm drive to the cable which runs in the inner end of the brass fitting. There is a further washer between the worm drive / cable attachment and the gearbox body.I have photos of disassembled gearbox which I will try to upload if this post is OK. Hope this helps. PhilD.
Speedometer gearbox disassemblyHi I have just joined the forum and am based in Leeds UK currently restoring 1964 CB72 and 1964 CB77 Was planning proper intro and restoration thread but saw your query and have recently dealt with same problem myself as one of my speedometer gearboxes was seized and I had to work out how to take it apart as parts diagrams I have don't show gearbox inards. If you look at the gearbox from the inside you need to lever out the oil seal, there is then a fiddly circlip to remove which overlies a washer holding the ring gear in place. Behind the ring gear are two shims. From your post sounds like you have got this far. The brass end to the lower part of the gearbox is secured by a small brass grub screw which is situated on the lower surface. When this has been removed the brass end cap can be removed from the gearbox either by gripping the end careful in a vice and puliing and twisting or if it's to tight by hitting the opposite cable drive end with a small punch which will drift it out. The brass end cap has a serrated margin and is a simple press fit in the gearbox end when removed there is a washer and then the worm drive to the cable which runs in the inner end of the brass fitting. There is a further washer between the worm drive / cable attachment and the gearbox body.I have photos of disassembled gearbox which I will try to upload if this post is OK. Hope this helps. PhilD.
Thanks for the excellent response. I took mine apart just like you said. Did you find a washer on each end of the worm gear? I only found one on the end by the brass piece I removed. It's possible the other one flew off when I tapped out the worm gear/brass bushing. If it was there I can't find it. Thanks again for your help.
Speedometer gearbox disassemblySorry my post somehow appeared in triplicate. Yes there are two washers on the worm gear, one next to the brass end cap and one inside between the worm gear and the gearbox body. I have disassembled both of my gearboxes and each had two washers though on one of the boxes the inner washer was very thin, I did wonder at first whether the inner washers were shims but I can't see why clearance would be critical and think that the thin washer was just very worn. I do remember the inner washer tended to be left inside stuck to the gearbox body with grease and sometimes fell into the centre of the gearbox body when the worm drive was removed ( I had to disassemble / assemble my seized box several times whilst cleaning rusty corrosion off the cable fitting to clear the seizure and restore smooth running ). I was able to reuse my oil/grease seals though was concerned that removal after 50years may have wrecked them. The seals are 34 x 48 x 6.5 which isn't a standard size and since the parts diagrams don't show the inside of the speedo gearbox I don't know what the Honda part number is or whether they are still available, perhaps one of the forum gurus can advise. UK bearing / seal suppliers do list a 34 x 48 x 7.0 seal which would probably fit as there seems to be enough room to accommodate an extra 0.5mm. I also had a slight problem with the large O ring which runs around the circumference of the gearbox which expanded slightly when I applied a little heat when I was trying to work out how things came apart.. It then wouldn't sit properly and was interfering with free running of the gearbox in the wheel hub. Again I don't think replacements are available as it's far larger in diameter than any I could find. I bit the bullet and removed it completely managing to keep it intact. After the groove in which it sits was cleaned out it went back in with nice even tension and worked fine.
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