Twisted but where?

[Al]

Assuming i have understood youre plan i would say that there is next to zero chance of getting the outcome you need. If youre intending to strike the sacrificial 'slug' sideways i think it will bend the holding bolt first, bend the yolk centre tube / damage its thread and oval the headstock where the bearing sits before it bends the frame. There will be too much 'bounce back' in the frame tubes and no incentive for the frame to move back to an acceptable position unless you either; heat it first or pre-load it significantly in the direction you need it to move.
If you were intending to brace the bottom of the headstock back to the wall with a bar or piece of wood, it will likely just collapse the headstock tube in on itself before it 'rotates' it.
Its just my opinion and sorry to say it but i dont want to see the situation worsen and its easy for me to say this too because in similar situations i have been fortunate and had all the options and facilities available to me in the workshop. Delighted to be proved completely wrong.
AL

[moizeau]

Thanks for your advice and knowledge Al. I was planning to use a piece of oak, shaped as much as possible to share the impact, between the lower part of the headstock and the wall coupled with a ratchet strap to hold the oak in place and pull the frame towards the wall then 2 further ratchet straps attached each side of the frame near the lower engine mounts to the walls either side. The slug bolts down tightly onto the lower headstock bearing adjusting nut (the top locking one is removed) and then over tightened making the steering a little stiff. I was hoping the bearings would protect the headstock tube. The weak link may be the thread section of lower yoke. I've asked my mate to shorted the slug by 7mm in order to use almost all of the threads. This should gain me just over 4 threads, roughly an extra 25%. I realise this is a risky procedure but I haven't got any alternatives. I will be lifted on a pallet to strike the slug crochet style as this will give a more controlled hit than trying to swing the sledgehammer horizontally.

[moizeau]

Partial success. I decided against the sledgehammer method because it wasn't controlled enough and I had no idea what forces would be put on other parts of the frame so used this method

I had to adjust the positioning of some ratchet straps as the car jack was trying to push the bike over. I over stressed the headstock expecting some spring back

which it did, so not completely there yet, but gained about 2mm so the method works.
What was confusing was that the handlebars in a straight position gave the front wheel even more of a turning left position so was worse in some respects but wheel alignment, though not spot on, had improved.
Now that the headstock was improved I rechecked the forks. Still 2 degs out left to right and fore aft they differed by 1 degree. I removed the top yoke, front mudguard and wheel. The bottom yoke is bent and I'm presuming the top one is as well. With everything removed and the headstock more vertical it is clear to see with the naked eye.
So now on the hunt for a set of yokes.
The headstock still needs 'adjusting' but I'm happy that the method works.

[Al]

Thats more like it in my opinion. If you hit it, the instaneous force applied is only acting locally and the energy cannot be dissipated or broadly transmitted so something gets bent.
A couple of years ago i was asked to do a repair to an Americam classic car chassis in a friends garage with limited facilities. Youre first pic put me in mind of it. It had a massive whamoo in the front RHS and i used a piece of 4x4 and an 8 tonne bottle jack and a little violence and managed to get back the shape to within 1mm and re-establish the caster, camber, KPI and Ackermann in short order. Car was resto-modded and feedback says it drives like a modern car now its back on the road.
AL

[moizeau]

Did some more today. Couldn't improve it any further with a jack alone because no matter how many straps were attacked it was tilting the bike and lifting the rhs of the ctr stand..
The yokes are buggered and good ones should be arriving this week. So a slight melange of plans. Stress the headstock and then larrop it. Got it to within a mm of off vertical. Knocked it the head (literally) for the day until the good yokes turn up then I can see if any efforts have made a difference with wheel alignment.

[moizeau]

Stuff turned up

Very impressed with the seller, well packaged, good communication and left lots of bits on that other sellers take off and sell separately. Going to throw them on tomorrow to see where I really am.
flashbackmoto.fr

[moizeau]

It's back in one piece.
The clinometer on the forks measure a flickering 59/60 on each leg. They were 2 degs out from each other before, so the little bending but manly the new yokes have done the trick.
Whilst it was stripped I was having a nose at other parts of the frame. The bottom rhs front engine mount plate is slightly bent and the engine a pretty much touching the frame on the lhs so it's had a massive wollop at some point.
The wheels are still out of line by an inch but are now parallel so when the handle bars are in a neutral position the front wheel actually points forward. Took it round the block and it seemed quite odd looking at the bars in a normal position after 4 years.
So the plan now. Change the front tyre, give it an oil and filter change, sync the carbs and check the mixture and run it.
When I'm back in the UK, for whatever reason, strip it to a bare frame, chuck it the van and give it to Motoliners.
I've improved it a bit and also learnt a lot, including my limitations.
Although not right, I'm reasonably happy and the bike has been improved.
Thanks for all the advice and comments made.