Frame Issues

[gleno]

These forums have a way of focusing your attention on issues that should be blindingly obvious.

Following discussion in the thread 'Now this is a real frame brace' I focused in on some very V-max handling issues and discovered something disturbing that may well affect other riders.

I need the help of any rider who can take some close up digital shots of the frame and post them to this site.

This is what I need

1) Remove the swingarm pinion covers from each side of the bike.
2) Take a photo of the welds that secure the pinion mounting sleeve to the frame.
3) Post the pics to this thread.

That's it.

I've attached some pics to show where the mount is on the frame,

The yellow line in the photo's I took from the workshop manual shows where the welded seam runs (or should run) around the outside of the pinion sleeve mount.

The red marks in the cross section drawing show where the weld seam is on the external view of the frame shown in the photographs.

So Can you help?

I suspect that this may be a major source of misalignment and structural weakness in the frame. I am trying to determine whether my frame has metal fatigue/bad welds/crap manufacturing = frame flex.

A visual comparison with your frames will establish this. :cheers:

 

[gleno]

I took some photo's of the pinion mounts on my bike to show you what I'm on about.

The first photo I've attached shows a left side pinion mounting sleeve in the frame. (not my bike). The sleeve is clearly seen as the lighter coloured inner ring. For want of a better description, this is a piece of pipe (tube) welded into the frame and your swingarm pinion installs inside and through it to you swingarm bearing.

NOTE: This has a continuous weld around the sleeve.

The second photo shows right side sleeve on my bike. It also has a continuous weld around it. I have outlined the weld to make it obvious.

The third photo shows the left hand side pivot on my bike. The weld is NOT continous (unlike the first example photo). I have outlined the welds in yellow. The red outline shows the area with no welded seam. This is as it came from the factory assembly line.

The frame material that supports the sleeve is extremely thin and yet it is expected to support the twisting forces of the swingarm, driveline, rim, tyre and road with so little bracing??!!!

What is the point of bracing a frame (in anyway at all) if this is all that supports the swingarm?

Is this the same on your bike?

 

[Buster Hymen]

Intriguing! You bring up some very good points. :hmmm: That is a good bit of investigation. I'm going out tomorrow to check mine out and take some pictures.

 

[shawn kloker]

When i gussetted my frame these welds looked good that you are talking about.If you look at the frame from the rear you will see a rectangle wich the drive shaft pokes through.I added a gussett into each corner of the rectangle.

I do not know if this really did anything but I saw it done elsewhere on somebodies website.I also braced my swingarm myself while I was at it.Solid mounts and frame braces and now it does not flex hard in the turns.What helped the most?Frame braces seemed to have done the most for me.

Those crappy welds should be repaired,preferably tig welded.

 

[broook]

I just checked mine and the right side is welded all around but the left side is almost identical to your photo. A couple of small tacks.:confused2:

 

[Lew L]

If there was much movement/flexing there the paint would be cracked (maybe even the metal). It's been my experience that the cracks often appear at the juncture of the weld bead and the base metal.
Most of the wire used in factories or automated welding has a tensile strength of 70K PSI and most of the cheepass steel used in these older frame designs is much less at 40 to 45K PSI.
I've had stability problems when:
* Tire pressure has been off
* Tires are getting worn out.
* Rear wheel alignment was off
* Steering head bearings were a bit to loose.

 

[gleno]

I just checked mine and the right side is welded all around but the left side is almost identical to your photo. A couple of small tacks.:confused2:

Thanks for that. I was beginning to think I got the frame they built 5 minutes bfore quitting time on Friday afternoon.

What year model is your frame?

 

[broook]

Thanks for that. I was beginning to think I got the frame they built 5 minutes bfore quitting time on Friday afternoon.

What year model is your frame?

It`s a 1999. Perhaps they were both built on Friday evening.:confused2: