Whats causing this?

[tony27]

Any ideas on why my front guard has spread far enough to touch the fork legs & hit the wipers under compression.
It's a 73 style guard from VMXracing & has only done 2 meetings, noticed it part way through the day at Taupo & had to release then reseat the wipers after each race
Is my best option to replace it with a Falta style guard or is there a trick to mounting them that will stop the problem?

[Davey Crocket]

Just trim it with a stanley knife.

[tony27]

Actually have thought about riveting a small piece of aluminium on the inside to pull the sides in but think thats really just treating the symptom rather than the cause
The Falk guard I replaced with this had done the same thing except the sides went inwards & hit the tyre

[pokey]

Ever tried to bend a pipe without a pipebender? it creases dont it.
Now imagine your guard is a tube

The front of the guard is bending down every time to forks compress on every bump. That means the energy has to be transferred someplace and thats to the part thats not bending ,, The mount.
all that force is going into the sides ...The sides are steadily being forced outwards and staying there.

answer 1;  As said trim the sides around the fork tubes. (fix symptom)
answer 2; A long  brace on top of the guard to stop the guard flexing (fix problem)

[Davey Crocket]

If your good with a heat gun you can reshape it aswell.

[DR]

My ignorance showing here but I assume the underside where it bolts on is all flush and on the same level..mounting screws could be distorting things otherwise..

[VMX247]

My ignorance showing here but I assume the underside where it bolts on is all flush and on the same level..mounting screws could be distorting things otherwise..

or bigger flat washers(underneath) to distribute pokeys force ideas. 
cheers

[tony27]

My ignorance showing here but I assume the underside where it bolts on is all flush and on the same level..mounting screws could be distorting things otherwise..

Has a high density foam pad under the triple clamp due to the stem sitting proud but thats standard according to the parts book
The Falk guard had a thin plate under it instead of washers, maybe I should refit that after heating & straightening the sides

[Mike52]

Is the guard mounted with 4 bolts outside of that centre rib??

[tony27]

It is but the rib doesn't extend to the mounting

[DR]

Near bet it's distorting at the mounts. In or out flex would depend on which guard, the rib position and where the screws are positioned on or near the rib. Common issue appears to be the foam pad. I'd try the solid mount again.

[pokey]

A wise monk, Occam, many eons ago said ;
"entia non sunt multiplicanda praeter necessitatem"

thats latin.. dead ducati rider speak.

this translates to.....

 "Why make crap harder than it already is when the simpliest answer is often the best".

Now go outside and grab a plastic bucket and press one side in.. holy crap the sides go out.
 Do it hmmm thirty times and see if its still round or a Bit fat.

I'll be in the main bar philosophising the world through the bottom of a cold beer glass. i can see a lot of unhappy wives seeing squished buckets tomorrow . hahahahaha


 rubber mount the guard to take the vibration and stresses and dont tighten it till it squashes or cut the sides orr... beef up the flex point

[tony27]

Heated out the bend quite easily while at work on friday, looks like I'll have to try tightening up the side bend a bit more because it still hits the forks when placed on the tyre. I'm guessing the shape isn't quite right which sounds to be normal for a vacuum formed replica

[Davey Crocket]

Hey hokey Pokey, thats should be everybodies thought of the day.

[SAABCOMBI]

fib/glass guard would be best for that model CZ.