Frame crack.

TeK9iNe wrote:

So really, you guys dont trust the JB weld that much?
It reportedly has a higher tensile strength than steel...

Absolutely not true.
JB weld will seal a gap, but it has NO tensile strength.

What you propose is absolutely unsafe.
I guarantee you that on your fist ride the JB will crack.

It must be welded.

Nice and freshly powdered :lol:

Pics comin soon... promise.

Cheers

My 73 frame is #10636 and I to have the famous Z1 crack.



mtkawboy wrote:

The bike with the crack is #03795, my other 73 Z1 is 11107, so maybe the problem is with the earlier frames. Im going to drill it and have it welded. I dont think Id want to do the whole bracing kit without the frame mounted in a frame jig although the steering heads are supposed to be welded crooked from the factory so they dont track right per a friend who raced the first Z1 in the country at Bonneville. They had to cut the steering head off and reweld them in a frame jig & true the front wheels to stop the head shake on the salt.

TeK9iNe wrote: [,,,]on the underside of the frame at the very back of the main lower frame pipe (just in front of the center stand cross-pipe weld), is a crack that goes half way around the pipe! [,,,]

I know its an old topic, but i had a very same issue. I discovered a crack in a lower part of the frame, it goes from one side to another.I had someone to weld it up, but i was thinking about the cause of it.





Its the rust which eats the frame from inside out. This is because these tubes seem to be air sealed, no vent holes. They start at he headset then go under the engine and end at the swingarm axle housing. No vent holes, and the most important no drainage holes, unlike cars what have such holes in the sills or even in doors.
So the water collects even from the moisture in the air, and its just a disaster waiting to happen.

I drilled little 3mm holes in each of these frame tubes, near the headset, to inject some WD40 as an antirust protection.
Anyway then just to see what happens i blew 4-5 bar compressed air into these holes, and this is what sprayd out of the welds, next to the swingarm axle housing.

First it was lots of black goo, its these black stains on the cardboard under rear wheel. So i poured more WD40 into the frame, and now its just light gray mayonnaise coming out with compressed air. And mind you this picture is from the other non-cracked tube(!) on the outside it looks perfectly healthy.

I don't know what could i do at this point but pouring more WD40 in, hopefully it would disperse all water. Ideally it would be to drill another holes at the lowest part of these frame pipes, but i just put the exhaust on, so no access.
Anyway i just wanted to throw that in, as a warning, even if your lower parts of the frame is shiny and fresh eg from some oil leak, the inside could be filled with water.

I believe linseed oil is standard practice in the welded-tube aircraft business. The frame is manipulated so the the oil covers the interior of the tubes, then the access holes are permanently closed with rosette welds. It's all academic in this situation since the damage is already done.

It is surprising how bad these frames can rust, from inside out caused by condensation. Also what might look like just light surface rust reveals a lot worse once the you go down to bare metal.


I had an '82 GPz550 H untrack swinging arm like this, quite shocking how dangerous it was, only noticed as I was prepping it for paint. These swing arms were originally in red too, a black one would be even harder to spot. Both my ELR and 81 GPz550 needed welding, I expect the 750 will also.

This is a good point to be aware of now these bikes are well past their design life and even past Kawasaki's very generous 25 year parts supply policy.

Not such an issue if you live in sunny California, but in damp and rainy Europe where bikes often get stored over winter it is well worth checking.

ayeckley wrote: I believe linseed oil is standard practice in the welded-tube aircraft business. The frame is manipulated so the the oil covers the interior of the tubes, then the access holes are permanently closed with rosette welds. It's all academic in this situation since the damage is already done.

+1
and wd40 has water in it, try something else.


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Anything I used WD40 on seemed to rust faster after a few months.