Straightening Forklegs

The patient is a 46mm rwu fork from a ZX9. The bend, of the order of a
couple of degrees, is localised in a narrow band just below where the
fork passes through the bottom triple clamp. No cracks or other marks in
the chrome, and the section of stanchion involved in the wheel travel is
unaffected; the fork moves through the 150mm or so of normal travel
smoothly.

Seems like a trivial enough repair to me. What do wiser heads think?

 

Large press , a dti and some edges , going to sell it ?

 

They make dti's now?

Sorry. Should've made it more apparent that I'd be pulling the fork
apart, throwing the stanchion at a bloke in greasy overalls and saying,
"It's bent, and cahns on ausmoto reckon it's fixable. Can you fix, please?"

The first rule of IK Labs is, "Parts come in, complete bikes come out."

I've got the other fork, and a fair portion of a whole bike (still need
a couple of trivialities like a frame), so, if this one can be
straightened, that's one less major component to have to track down.

 

wouldnt Laurie be the man for this one , sounds like a viable job

 

Laurie would, but him being a pair of $15 postages away, this is some of
that looking stuff you're supposed to do before you leap.

 

Dial test indicator
IF the chrome survived then there is a strong chance you will get some
one to sort it , but how much is a wrecker replacement or new one ?

 

I thought this is the sort of thing that your Uni has a phone for

 

In aus.motorcycles on Sun, 18 Sep 2005 20:10:16 +1000

Couple of degrees is a lot.

When I've seen it done, it's done in a press, and the fork leg wasn't
visibly bent, only rolling it on a flat surface showed it wasnt true.

I also think that if it's that far up the leg that it will be hard to
straighten, as there's not a lot of leverage.

Zebee

 

It can be done , BUT there will be a risk involved , the chrome may
crack and the leg will be less strong the a new unit but of course only
an experienced tradesman will determine the final answer. I would think
most good engineering shops would handle it .

 

I've straightened trail bike fork tubes at work without problems. But
I'm not sure I'd try it on a road bike that's going to be used at PI at
250+.... your call


G-S

 

Come on Guys where's "ya have to split the cases" answer??
Lushy

 

you mean he hasn't already to get the front end off ?

 

Laurie Alderton in Sydney.

Bob Martin in Melb.
Typical spot for a front-ender, any creases at the bending mark and it's a
bending-tube for the workshop
(i.e. for straightening fairing-frames).
My personal golden rule: laid side-by-side next to a straight tube, if it's
out by more than 8mm at the bottom, it's history. If it's creased, it's a
junker, too. Same for something that pops the chrome/ coating during
straightening, hardchroming and running around plus the straightening itself
comes close to a new one, $$-wise.
And DON'T listen to any knucklehead who mentions a 32mm socket driven
through the leg with a piece of tubing and a 4-pounder....
cheers
pete

 

The ZX9 has rwu forks with 46mm inners.
The YZ has usd forks with 48mm inners.

Dirtbike forks cop more of a pounding than sportsbike forks, and have
the construction to reflect that.

Wall thickness on the Nine fork uppers is 2mm. From what I've been led
to understand, the thicker the material, the bigger the chance it'll
crack or crease when being straightened... this accurate?

 

It's a spare part, though. It's not associated with any cases.

If it's any consolation, I've got a CBR400 engine which'll probably be
coming apart this Sunday.

 

Spend the fucking $12 postage and find out. Bob Martin's
charged me $55 for a R100GS fork leg, came out perfect.
No guarantees, though ... sometimes they don't survive the
procedure even if they don't look too bad to start with.

-----sharks

 

That is my understanding also... and yes dirt bikes have big forks
now... but I'm talking XR not YZ

G-S

 

DR BOB is the cure , the only other option is training wheels

 

Don't forget the American Car Club Nationals at Queanbeyan Showground (bikes
and tractors too). Think I should check BT's booth for him on the way past?

 

You bringing the Trans Am down?