Twisted fork

[marroinia]

Hi everyone!

As I was riding on a long straight road, I looked down at the top bridge and handle bar, and it seems that I slightly turn right to go straight.

So back home, I took two aluminium sections and used them as winding sticks. Eyeballing down on them, there is no doubt the wheel is pointing left, (or the handle bar is coming backward on righthand side.)

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I turned the tubes in place but nothing happened. I unscrewed the right axle holder and turn the tube, noticed no axial or radial move toward the wheel axle, same thing on the other side. As far as I see tubes are straights. Handle bar is brand new from DSS, no cracks in the bridges.

I unlocked the steering stem nut and top sides screws, tryied to move the thing and everything came in place, but when screwing everything tight the problem is back. Whatever I do.

Any idea someone, something I missed?

What is the way I'm supposed to tighten the top brige? stem first, then the two side screws or the other way?

Thanks for reading

[Bryanj]

Leave everything tight and stand in front of the bike with a leg clamped tight either side of the wheel grab the bars tight and twist straight plus a bit to allow for springback

[marroinia]

Nothing moves, even whith the stem bolt a little bit slacken, my knees are sore now I try to fully turn on left to pull using the bottom bridge stopper on the frame, all efforts are useless...the winding sticks are saying it's twisted.

The mudguard is not very lined up with the wheel, it's obviously following the fork false. Can it twist the fork by itself and be the faulty one?

If I can turn a tube easily with no hard points and without slacken the other one then I know it's straight.

I don't think the iron bridges can bend, they will break before, could it be something normal for these 70's bikes to be a bit imprecise? Am I chasing ghosts?

[K2-K6]

It's just possible the bottom triple clamp is bent so that the bores are not aligned.

You could try and drop both the stanchion down out of the top clamp to observe how they align when free from being held. That may give you an idea of geometry as they should just point to the correct place to go straight through.

Warning, it may be more of a task to get them back in if there's significant alignment present there.

[marroinia]

ok I will try that,
I dropped them once to change ball bearings ( just the balls not the races) and I had to lightly tap the top clamp with a wood mallet to fit it back on the tubes, but it wasn't forcing that much.

[Bryanj]

The yokes bend easily and have straightened loads the way i suggested but if yhat dont work it suggestes you need to change the lower yoke and maybe the top one as well

[marroinia]

Well, I think the top yoke is fucked.

I used a piece of glass across the stanchions to see geometry while only half out of the top yoke, they are dead true. If I drive them back up they go twist...

The gap between the top clamps screws , where its pinching, are not flush, I bent them back, now the twist is worst. The bike is unusable  I will bend as it was, I want to ride...

[marroinia]

I used your method Bryanj, and everything came back as it was before I messed with that fork.That will be the good news of the day! I also tryed to push on a wall corner, it straightend the fork but it springs back. I can't do more...

I also have a gap between the left fork leg and the speedo drive, that remember me that thread:

http://www.sohc.co.uk/index.php/topic,22727.msg203415.html#msg203415

No christmas present for the kid and wife this year, I need new yokes!

I think buy the bottom one first, as I read it's the first to bend.

Is it possible to pay someone to straighten them like the frame ?

[allankelly1]

Hi

I had a very badly bent set of yokes on my Rd bottom yoke was so twisted it was out by over 6mm and sent them to Motorliner in Maidstone as  they are pros at straightening yokes and frames


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[marroinia]

So it can be done, good to know. There is a bike shop 1h ride from my place, they have good reputation, (and cb four they refurbish ) I will ask them if they do it or know somebody. Maidstone is 12h drive!

Thanks everyone for advices! I'll let you know if that's fixed.

allankelly, how much did you pay for that?

[allankelly1]

I posted mine to motorliner

As for cost I cannot remember but I think it was around 50 squid I will see if I can find the email


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[marroinia]

Hi!

I planned to sell both wedding rings and buy brand new set of yokes on cms for 800euros  , but my wife told me better money to ask Steve at

https://www.400fourbits.co.uk/#running

So I did, it cost me less than send to UK for straightening, and nobody here answers to phone call or emails (how strange...)

Have to fit them on the bike now, and I'm thinking about checking frame truth with a vertical laser and wheel alignement, long way to go...

[taysidedragon]

Hi!

I planned to sell both wedding rings and buy brand new set of yokes on cms for 800euros  , but my wife told me better money to ask Steve at

https://www.400fourbits.co.uk/#running

So I did, it cost me less than send to UK for straightening, and nobody here answers to phone call or emails (how strange...)

Have to fit them on the bike now, and I'm thinking about checking frame truth with a vertical laser and wheel alignement, long way to go...

You'll get there. I hope the new yokes fix the problem. 🔧👍