SOHC.co.uk Forums > CB750

Bent steering tube.

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Johnny4428:
Purchased replacement off eBay. Let’s hope it’s straighter than the one I have. Good luck with your repair Rob! A few on eBay but just one that suited my K3.

Rob62:
Cheers! and good luck with the replacement johnny. When my replacement came it looked ok but i noticed on close inspection that the lower race was cracked (as it was on the original stem) and the distortion was right at that point where the race fits on the stem, as with the original, so not easy to detect until the race was removed. All the weight of the bike is basically loaded onto that lower race and I don’t know if its long term forces that gradually distort the stem or a single impact. The low milage would be an argument against that, but then the usa users possibly spend more time riding on unmade roads in certain districts....? I guess it doesn’t matter how it happened but I am a bit concerned that the metal could be stressed, it looked ok but who knows. The material Honda used would be tough and not prone to fracturing but those properties also make it slightly soft and therefore able to distort under load... Its a job I need to tackle before the spring... My brother has a little myford which is handy as I am a turner by trade but don’t have my own lathe... but the lockdown is keeping me out at the mo.

Johnny4428:
Yes indeed Rob very annoying when the replacement is no better than the one you had already. Indeed tremendous stresses on this part of the bike. Especially with a knock to the front. If my replacement isn’t straight I will probably cut my losses and send the original away to be professionally straightened. Come to think of it there was cracks in the races on the yoke of my bike too.

Bryanj:
The stem tends to bend in a frontal impact, imagine the force applied when you bend two fork tubes (common replacement back in the 70's) and that is transferred to the lower yoke where the stem is held in place by the bearings so the yoke twists the stem where it is welded in and in that tiny gap between yoke and lower race bottom edge.

Insurance companies would not pay for a strip down to check and only for obvious damage, I once had a CX where after accident rebuid I had to drop the forks through the yokes to get it to stand on the centre stand, wheels perfectly in line, handled fine so explained to owner and he accepted it back as the insurance would not replace frame

Johnny4428:
Received a nice straight one off eBay DK. Currently at powder coasters. Thanks to Nurse Julie helping out with courier to Orkney.

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