Project Z750 part 17

So, I now have all of the calipers dismantled and ready for cleaning and polishing.

I have been doing some searching on the web about cleaning carburetors (for the CB750) and found soda blasting. This is taking an air compressor, attaching an extra hose to a nozzle and using that hose to feed bicarbonate of soda through the nose similar to sand/bead blasting.

using bicarbonate of soda is supposed to be safe on delicate parts as it is a soft material. it's also water soluble so I can soak parts after blasting to get rid of any left over soda.

I have a small air compressor so I thought I'd give it a go and see if I can get the calipers clean using it.

I got some clear tubing and made a cut in it. then I fitted it over the end of the nozzle and used duct tape to try to seal the connection. The other end of the tube was put into a tub of baking soda, and I fired up the compressor. it took ages to pressurise the tank. I wanted to get it up to 100 psi, and it's only a little compressor. it seemed to take an age, but I guess it took around two minutes.

once it was up to pressure, I pointed the nozzle at the caliper and pressed the trigger. it was fun watching the soda fly up the tube and when it hit the caliper some of the gunk was blasted off. It was working. of course it didnt work for that long. the duct tape seal didn't hold for very long and as soon as it leaked, the soda wasn't being sucked up from the tub and I was just blasting air at the caliper.

Having proved that soda blasting could work, I tried to re-seal the nozzle/tube junction, and gave it another go. it worked for a while but started leaking again. well at least a little bit more dirt was gone.

So soda blasting will work, I just need to figure out how to connect the tube onto the nozzle and properly seal it.

Comments

Project Z750 part 16

The piston puller has arrived. it looks like a pair of pliers, but works opposite so that when you press the handles the "nose" of the pliers expands. the idea is that you put the nose into the piston, grip very hard and turn and pull the piston so that it comes out. the theory is great, but actually using one isn't. in use you are trying to grip as hard as you can, and at the same time trying to pull the piston out of the caliper (as well as maybe turning it if it's stuck like mine). it took a herculean effort to get one of the pistons out, I was gripping as if my life depended on it, trying to twist the piston and pull it out of the caliper. when it turned (a little) it gave me renewed hope of getting both pistons out, and eventually the piston was out, so just one more left. so now on to the fifth and final brake caliper piston. I put the piston puller tool into the caliper, gripped with all my might (no laughing please) and twisted. Well something mo...

Project Z750 part 18

I have done a bit of reading on how to clean brake caliper pistons, and found an article that said you could use fine wet and dry to clean corrosion off them [ http://www.motorcyclenews.com/new-rider/choosing-kit/2006/november/jan26-05-how-to-service-brake-calipers/ ]. as it suggested using 1500 grit wet and dry, I decided to be cautious and start with 3000 grit. I cut the wet and dry into strips about an inch in width. I put some wd40 onto a strip and started polishing the rear piston. After quite a while I started to notice the difference. it was getting cleaner. well, it was working, but it was going to take a long time. well, I was patient and I really didn't want to rush it and ruin the pistons. Over the next couple of weeks, I polished all of the pistons using the 3000 grit wet and dry. As it seemed it was going to take the rest of my life using 3000 grit wet and dry, I decided to take a risk and bought some 2000 grit. yep I was really pushing my luck here. I cut the 20...

Project Z750 part 14

I thought that some photos would be in order rather just all that plain old boring text, so here is a front caliper and it's pistons: This is the caliper before I managed to get the slide off. the pistons show a before polishing started and part way through. Here are the pins that hold the pads into the calipers. again you can see the before and part polished (I hope you can tell which is which) I thought I would show a picture of the rear caliper in pieces: there are more bits for a single caliper than I realised. The rear is a single piston caliper. and one of the front calipers. the front calipers are twin pistons (as I hope you noticed) I dont think that I will be able to remove all of the corrosion from the caliper pistons, so it looks like I will be getting all new caliper pistons. I'll order them once everything has been cleaned thoroughly.

My Ramblings

Search This Blog