Is my frame bent?

[a7avenger]

I noticed today that the diagonal brace tubes that run to the headstock of my frame have a slight kink, as can be seen by laying a straight edge alongside-

http://img231.imageshack.us/img231/9241/cimg1217.jpg

Is this normal? because it got me wondering, the front wheel had obviously had a knock at some stage and has a very minor buckle, also the front spindle was slightly bent. It all seemed very slight until I noticed the above.
I have measured the distance from the lower headstock to the first crossbrace, it comes out to roughly 90.6mm-

http://img828.imageshack.us/img828/1115/cimg1222n.jpg

Does anyone have a bike which has the same frame type who could measure this dimension to check against mine, it's a 2001 M600, I just want to make sure that it has not been thumped hard enough to push the headstock back at the bottom, in effect making the forks stand more upright.
I'm just about ready to start reassembly and the last thing I want is to strip it down again, the frame has just been powdercoated.:worried:
Cheers for any help.

[Dukedesmo]

I have the bare frame on the bench waiting for paint but it's tricky to get an exact measurement as I have welded a brace in between the points you're measuring, but my frame (from a '99 M600) measures around 92mm at that point.

[pooh]

Try measuring diagonals it will give you an idea if it has been thumped chances of it being a straight on hit that bends everything perfectly inline is almost impossible. Also set the frame up level at the headstock end with a decent spirit level then check the level at the back of the frame. This will give you a fair idea if the frame is straight but don't be surprised if it is a little off, that's normal Ducati.

Ian

[utopia]

I have a genuine ducati workshop manual for my Y2K M750, which gives some dimensions for checking the frame. I'm not sure if all frames are the same.
Unfortunately, I'm not able to reproduce the diagram, but maybe I can describe the relevant features.....
If you set the frame on a flat, level surface, with the front engine mount 32mm higher than the rear engine mount (centerlines), the headstock should then be at the required angle (24 deg +/- 15 min) from vertical.
If you can then drop a perpendicular from the centre of the lower face of the headstock tube to the aforementioned flat, level surface, the centreline of the front engine mount should lie 315mm behind that point.
Also, the length of that perpendicular should be 239.5mm.
Hope that makes sense.
Like I said, I don't know whether your frame should be the same as mine, but I would have thought that similar information must be available for other frames, if you can find someone with the correct manual for your bike.

[Dukedesmo]

Unfortunately, I'm not able to reproduce the diagram, but maybe I can describe the relevant features.....


This one?;

http://www.ducati.ms/gallery/files/9/3/7/0/m900_frame.jpg

From an M900 manual but I think all the frames are the same for the first generation Monster?

[utopia]

Thats the one, thanks.

[a7avenger]

Great work guys, thanks very much.
I have spoken to somebody at Maidstone Motoliner today and very helpful he was to, apparently the M600 has a slightly steeper head angle than the 750's and 900's coming out at 23 degrees from vertical or 67 degrees from horizontal.
I have just set up and measured the steering head angle with the C/L of the front engine mount 32mm higher than the rear, the angle as near as I can determine is 68° 40' from horizontal, or 21° 20' from vertical so 1° 25' out of max tolerance. The headstock is perfectly upright though, so that's good point.
I'll have another word with motoliner on Friday to ask if this is enough to worry about, if not from what he was saying they have to heat the frame to tweak it back to its correct goemetry, so there goes my newly powdercoated finish.:eek:

[Dookbob]

You might be able to adjust out that 1 degree and 25 minute difference by dropping the back end. Or leave it alone , that amount of difference could be equal to raising the back end of an accurate frame, and so quicken up the steering nicely. I think that Motoliner might tell you something similar, unless they need the work that is.

[utopia]

And don't ignore the potential for error in your measurements. I'm sure you've done a good job, but even so it must be hard to be accurate without dedicated kit.
Maybe its worth setting it up again, using totally different kit, and then averaging the results ?
And/Or perhaps the Maidstone folk could do a more accurate diagnostic check, before you commit to much cash, or paint.
Also, further to Dook's comments, if you're on the tall side (?) you could raise the front instead of, or even as well as dropping the rear. They're low bikes in the first place.

And, sorry to raise the issue, but what are your forks like ?

[a7avenger]

I see your point Utopia, I'll try another setup and make some ali V-blocks today.
The forks are perfect, to perfect!
Maybe they have been replaced?? Who knows the history??
Cheers.

Steve.

[a7avenger]

Checked it again today using some purpose made V blocks on a surface table, got the same reading within a few minutes of a degree, the headstock is completely vertical side to side.
So it definately has had a "nudge" enough to increase the bend on the lower trellis tubes where they angle into the headstock. I reckon it was crashed and had a new set of forks fitted, maybe whoever fixed it thought that the frame was OK to go? Trigging out this 1° 40" error comes to minus 18.54 mm off the wheelbase over the length of the forks.
The give away is the slight kink in the diagonal tubes nearest the headstock, so any prospective Monster buyers take note.
I'll see what motoliner say on Friday.

[Pedro]

Without being to funny, if you have any doubt about the frame get it jigged and checked properly by a Duke dealer and inspected for cracks etc. If it has had a shunt there may be some hidden damage under the paint. If it's out, then it can be sorted.

[rollo22]

Have a look at this lot
motorcycle-frame-straightening.co.uk