Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: Johnny4428 on January 16, 2021, 11:35:41 AM
-
Apparently I have a bent steering tube. Never even noticed, but the guy at the powder coaters did. Is it viable to try and straighten or should I replace?
-
Do you mean the actual frame headstock tube thingy is bent?
-
Tube on the bottom yoke. Sorry maybe called it the wrong thing!
-
Not really viable to repair as there are used ones out there depending on model
-
I have a similar issue on my K4... the stem is not bent as such but is slightly distorted right at the base whee the lower race presses on. I did buy a spare when I was doing the resto but that also has a very slight distortion in the same place. The bike rides great but i can never get the bars to be pointing absolutely perfectly straight which I suspect is due to this. I obviously don’t know how this happened, whether it was due to a minor front end (no other evidence of this) or whether its just wear and tear, usa dirt road riding, whatever.... The stem tube walls are fairly thin and would probably be fairly soft material too. As I have a spare lower yoke I am planning on turning off the lower weld and making a replacement stem to press back in. You can buy a modern replacement from a place called cognitomoto.com but they are ridiculously expensive.. Anybody with a small lathe could make some, they could probably make a few bob selling new stems on here. 😄
-
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.
-
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.
-
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.
-
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
-
Received a nice straight one off eBay DK. Currently at powder coasters. Thanks to Nurse Julie helping out with courier to Orkney.