Twisted but where?

[moizeau]

Cheers, I'll download the one you use and try it out

[moizeau]

Got a Clinometer and went for a play.
Checked everything possible, horizontal brace under the seat, the horizontal bracket that bolted to the frame rear of the fuel tank, both were the same. The 2 outside horizontalish spine tubes, same, each fork, same but the 2 forks differed by 1 deg. the rh one is more upright. After having put it back together last weekend, time to take it apart again, only moreso. Got to be yokes or headstock. So now I've stripped the front end completely including bars, clocks etc.
This shows a laser picking up the centre of the rear tyre, which is vertical, and the lower yoke.

I knew the lh fork touched the oil cooler on full lock but with the forks removed it shows the difference between the lh and rh lock.

Partly caused by this

But mainly due to the headstock.
Spoke to MX bloke and went to the circuit and everyone looked very ponderous regarding a frame straightener. I was given one bike shop's no. big place that has a big showroom but apparently the head mech is getting on a bit and knows his stuff. I was told if he couldn't do it he should know someone who can. There was a place but it closed down 2 years ago, I know a chap in a retro car club that recommended the closed shop a few years ago, wonder if he's he's still got his tooling?
So 2 possibles, if not I'll have to get a bigger hammer.

[compo z1r]

Hi can u get access to one of these it’s a high tech laser u need one around the 2k mark for the correct features it gives u datum points and is self levelling correcting it self every second if the head stock is out front to back then it would only affect the rake ! Side to side is where u are having your problem so with the triple tree in place put in new bearings and lightly tighten set laser to centre of head stock and set horizontal to bottom of yokes this will give u the degree it’s out u will spot it straight away if it’s not head stock then triple tree is bent

[Al]

Pete, what would be the angle of the top surface of the swingarm at the front pivot subtracted fomm the angle of the side of the headstock? Hopefully 90!!
You can use a say; inch square piece of wood to step off from the headstock.
AL

[moizeau]

Compo, I can get my hands on something like that from a friend who does drainage etc. but not today so I've used mine again which does self level and has a cross but doesn't tell you angles.

The first thing I did was set a piece of 9mm glass level and set the bottom yoke on it.

It's not too clear on the photo but there is a decrepancy between the lh and rh fork tube clamps even though the centre tube was vertical. It also rocks. Here's a video. The laser can be seen better also.
https://www.dropbox.com/scl/fi/cmu48sj3 ... y0ov4&dl=0
Al, I could get a measurement underneath the swingarm pivot and it was 0 but with the bracing and welds around the headstock I was't confident with the reliability. I did get 88 both sides which makes sense but I could alter the reading by tilting the phone so not conclusive.
Next, refitted the lower yoke, set the laser to yoke centre underneath and also to the centre of the frame at the rear, then set the horizontal.

As can be seen the rhs is higher than the lhs and the headstock is tilted towards the left at the top (As it's looked at in the photo). I wanted to check other areas of the bike so set the laser up with the horizontal line set on the fuel tank mounts and the vertical on the top of the headstock.

With the lower yoke centralised I also measured the distance from the tail fin mounts to the slit on the fork clamp. There were within 2mm of each other. 119.0 cm and 119.2cm.
Z1Streetfighter, if you get a chance could you do this measurement please? Rear of the tail piece mounts on the side tubes to the top of the slit. Cheers
Another photo showing the top of the lower yoke tube's offset due the headstock. Again datumed to the underside of the lower yoke.

Dropped the top yoke back on and the forks in, set the bottom yoke central then lasered each fork using the top of the stanchion as a ctr point.

So unless someone can see a flaw in my methods I think the headstock is definitely kicked over and the lower yoke is potentially bent as well, therefore the top yoke also. Now just got to work out what to do next if I can't find a frame straightener. I have access to trolley jacks, chains, barn walls that are 50cm thick and tractors, steel bars.......just can't see it is possible without damaging some other part of the bike.

[compo z1r]

That looks like your correct Pete if u had the other laser it would show with mine I have software to 2D shadow block it like this ?

You could then set it up the front of the forks and it would show it out of true ! Looks like u need frame on jig and new lower yoke

[moizeau]

Possibly this
https://www.youtube.com/watch?v=Py4kHgtx8bA

[Speedie]

Hi, I haven't read through all the replies but for info I had my frame
checked at motoliner in Maidstone UK before I spent any money going forward on my project Z1000.
The headstock was out by 1/2in and the triple clamp also had to be
realigned. Total including vat £425 (2023) I also paid for local collection and redelivery on top.
Good to have the piece of mind!
Paul

[Al]

Have you come to any conclusions here or ideas' about where you are going to go with it?

Al, I could get a measurement underneath the swingarm pivot and it was 0 but with the bracing and welds around the headstock I was't confident with the reliability. I did get 88 both sides which makes sense but I could alter the reading by tilting the phone so not conclusive.

An online calculator of an acute isoscelese triangle having a length both sides of 150cm and an included angle of 2 degrees gives an opposite side of a touch over 5cm.
This is; the length of the forks, the 'off angle' of the headstock and the co-respnding displacement of the position of the front wheel. I think you said the front wheel appears to be approx. 1 and a half inches over so not too far off; calculated to observed.
AL

[CAT3]

A few points I'd like to chip in with, hopefully they'll make sense.

I'd be wary of positioning the lower yoke on a piece of glass & using that as a datum.
The glass will be flat, or at least flat enough for this excercise. However, because the lower yoke & upper yoke for that matter, is not a machined item, but cast it will not be accurate & flat along the lower surface.
What I'm suggesting is because of the inaccuricies in cast parts the lower yoke may well not be parallel when laid on the glass. So the stem may well lean a little one way or the other.
What you really need to do is mount the fork stanchions in the lower yoke & then try sliding the top yoke on & it should all line up with the stanchions & stem.
To check for frame out-of-alignment I'd remove the tyres from both wheels & clamp two, long known straight edges to either side of the rear wheel, (normally the rear is the wider wheel so there should be gaps between the straight edges & the front wheel rim). If you then measure from these straight edges to the front of the front wheel rim & the rear of the front wheel rim the measurements should all be the same if everything is perfectly aligned, (you might need to adjust the steering just to get it dead straight).

I suspect most bikes are not perfectly aligned, even from new so a little misalignment may well be quite normal & nothing to worry about.
I'm not saying that your frame/yokes are not out of alignment, but a little mis-alignment might not be a massive issue.

[moizeau]

Not sure where I am going with this atm. The headstock is definitely out of line as can be seen in the above photos, backed up by abnormal wear on the front tyre and the fact that I am permenantly turning right to go in a straight line. There are no frame straighteners near. Closest one is 3 1/2 hours away which means a day to drop it off and another to pick it up. I'm tempted to try and straighten it myself with the help of tractors and blocks of wood holding the frame in place then a metal bar down the headstock followed by an impact with a very big hammer. Can't be any worse than it is. I realise this isn't anywhere close to putting it in a jig and using proper rams etc. but an impact caused the twist so a reverse impact may straighten it a bit.
The other option is to put a part worn tyre on the front and ride as is then when I come back to the UK to see family at some point, stick it in the van and drop it off at Motoliner if they can turn it round in a few days.

[Al]

Did you have a chance to measure the rake angle either direct off the headstock or from the fork legs?
AL

[moizeau]

Al, Straight off the forks, 61 RH 62 LH.

[Al]

Thats encouraging; either 28 or 29 degrees rake angle which i am sure is about right but i dont have numbers for the ST.
The J's vary from 27 to 29 through the different model years so it looks like it was hit 'side on' and there is no significant frontal component to the damage. Be a shame to try yourself or Motoliner it and not addres that if it was there.
AL

[moizeau]

Bike has had the top yoke removed, forks dropped so both wheels are on the ground.
Mate knocked this up on his lathe

It's going to be bolted on here

Then it'll be strapped the the walls, I'll be lifted on a pallet with a big sledge hammer......
More to come at the weekend when mates and a tractor is available