CZ Swingarm Pivot Pin Removal

[Ji Gantor]

Support or remove engine. Remove end cap bolts. CRC all connection joints. Rotate swingarm and engine mount bracket to free up pivot pin. Apply heat to engine mount bracket, then shoot some CRC down into the pivot pin. The heat will make the engine mounting bracket expand and the CRC will cool the pivot pin making it shrink. Support frame and drift out pivot pin. These last two processes will have to be repeated time and time again.

Good luck and be patient.

Ji

[Ji Gantor]

To inspire the next person that has to do this.
The attached image is what it looks like when it comes out.

Just in case anybody thinks this is easy. I pulled apart my 10 ton press and rebuilt it with the chassis interlaced. The press refused to move the pin and the backing tube I placed behind the frame started to force its way into the chassis plate.

I will be replacing this system with a needle roller bearing.

Ji

[jimg1au]

thanks
i have 2 of these to do
i have herd this is very hard
jim

[Ji Gantor]

Hard like diamond.

I found that the engine mounting bracket was the anchor. When you start, you will feel that there is a grub screw or restricted flange holding it. The solidness will make you think that you are doing something wrong. Be patient and use heat and cooling. Before the CZ my ten ton press had only once not removed a bearing and in the end I had to cut that one out with a die grinder. Don't be tempted to take a hack saw and cut it out. I have been told this is another method. I feel the hack saw would do more harm than good and then you are still left with getting the pivot pin out of many parts.

Ji

[Ji Gantor]

Just to give you an idea of how hard it is to get these pivot pins out. The attached image is of my starter drift. It was perfectly round when I started.

Ji

[shortshifter]

There is an article on removing CZ swingarm bolts in VMX mag no28 2006.Everyone seems to have a horror story about this and as the article states it was a design fault copied from their road bikes.Old Yamahas seem to have the same problem and I just about destroyed a good frame getting a bolt out with a press once even though it was supported.I am enjoying your "blow by blow" descriptions Ji.Cheers!

[Ji Gantor]

Hi shortshifter,
Issue 28, may be someone can post that article.

The pivot pin was not easy by any means but I only spent 2 hours on it. I have spent 4 hours today working on one wheel. In the grand scheme of a restore it is just another job that needs doing. The important lesson to learn here is to pop the pivot pin out once or twice a year and give it a good greasing. I have spoken to some CZ restorers in the States and they tell me that you can drill a hole in the middle of the pivot pins cap bolt, tap a thread and screw in a grease nipple. This way you can charge the hollow centre of the pivot pin with grease.

I agree, you have to select the right tool for the job, if I had kept on going with the press I would have damaged the two fin plates that hold the pivot pin housing.

Thanks for your support.
Keep well.
Ji