85 250R Caliper rebuild... HELP!

[xman2rman]

I need some advice on what to do about the caliper pistons on my 85 250R. I’ve got 3 calipers and all have what I would consider bad pistons. They all have pitting to some extent and my concern is they will leak. My question is, what should I do? I’ve looked up the parts and they are not available. I looked up TRX caliper pistons and it appears only one of them is available. I’ve searched the forum for hours and all I can find is someone once said that a CR caliper piston was the same size. Can anyone confirm this and know what model or year may interchange? Now I know I can’t be the first person to run across this problem… so what did you guys do? Any and all help is greatly appreciated!

[xman2rman]

Maybe nonody's running rear brakes??? I never had them on my 185s... :(

[xman2rman]

OK.... I've been researching this issue a lot. It seems I can't find any other Honda caliper piston that will intercahnge. I've read somewhere that a CR plastic type would work but my research tells me they are 27mm in diameter and the ATC250R is a 25mm. I thinking about getting a CR set and having them turned down. Anyone done it or know if it can be done? What's my "other" option for a rear caliper? Can the 85 swinger/carrier accept the 450R bracket and caliper?

[Xowner]

Look into converting your 250r brakes to 450r!

[ailll1]

Does it help?

http://www.3wheelerworld.com/showthread.php/65919-250r-rear-brake-mod?highlight=250r+450r+caliper

[falloutboy]

I talked to a machinist once about having new pistons machined, but they weren't too hot on the idea. The reasoning was that that have such a tight tolerance, he wasn't sure he could make it exactly perfect. I kind of felt like I was being fed BS, whether it was a lot or a little....

[Stingray]

falloutboy,
If your machinist is worried about tight tolerances you need to find a new machinist.

[xman2rman]

Thanks for the link. I have 3 calipers with bad pistons and I hate to trash them. I'm going to check with my machinest and post up what he says about making the caliper pistons.

[xman2rman]

Just to let anyone searching the forums know, I ended up having my machinest make me new caliper pistons from stainless bar stock. He told me he turned them .001" smaller than original due to the properties of stainless. They have been installed and working perfectly for 2 months now and I'm glad I didn't have to convert my 85 set up. Anybody needing caliper pistions for a 3rd gen 250R, shoot me a PM and I'll see about getting you some made.

[rdlsz24]

That's cool, thanks for sharing. I junked an 85 R caliper in the past because the pistons were seized and a rebuild kit failed

Rob

[Xowner]

Just to let anyone searching the forums know, I ended up having my machinest make me new caliper pistons from stainless bar stock. He told me he turned them .001" smaller than original due to the properties of stainless. They have been installed and working perfectly for 2 months now and I'm glad I didn't have to convert my 85 set up. Anybody needing caliper pistions for a 3rd gen 250R, shoot me a PM and I'll see about getting you some made.

Whats the cost on these?

[Dirtcrasher]

If he only took off a few thousandths, then he cuts it and faces it, and a couple angles so they slide in. It should be a big deal.....

I can't imagine them putting the hollow hole in there, so I doubt it's necessary and just a weight thing.

As long as last cut is super smooth, your golden...........

[xman2rman]

I'll have to get a price, they were done FREE for me. He turned them from 1" SS bar stock. The original dia. is .9775 and he made mine .9765. They are hollowed out just like the original, less surface area to transfer brake pad heat to the caliper. You do have to use a block off plate because they don't have the E brake rod out the back. I'll talk to him this weekend and see if he's interested in making some more and how much they will be.