caliper pistons

flinty · Post by **flinty** » Fri Sep 14, 2007 12:44 pm

I've found my first problem!! I'm overhauling the brakes on the KR1S and i've found the brake pistons to be pretty badly mangled and pitted so i'm looking to put in new ones. Question is, are those piston inserts (insulators) essential? or can i just bung in new pistons sans inserts? How do the inserts come out?

any advice much appreciated, also any tips on where to source pistons and if necessary inserts? I've spoken to wemoto and they only supply a piston kit with the seals included, trouble is i've already bought all the seals....doh!!

mr_bungholeo · Post by **mr_bungholeo** » Fri Sep 14, 2007 6:16 pm

should be able to get the right ones from big k....probably the same as zxr400...any good dealer will know...the insulators are just that...they spread the load over the pad and stop heat being transfered to the caliper and boiling your fluid....best to leave em as they were made if pos.....or you could do the fireblade caliper mod(cheap on ebay) and an easy fit...or i think gsxr six pots go straight on....there's posts about it....

nate · Post by **nate** » Sat Sep 15, 2007 5:33 pm

Wemoto sell pistons, seals and dust covers... cheaper that my local Kwak dealer...

Just fitted 3 pistons and all 10 seals to my calipers...

(Whinge) Do people bother to check things when they own bikes... My calipers were ok but the seals were falling apart and 3 pistons were pitted to hell...

(Whinge over)

flinty · Post by **flinty** » Mon Sep 17, 2007 10:13 am

Thanks for the info.

Did those wemoto pistons come with the piston inserts or did you reuse the original inserts?

nate · Post by **nate** » Mon Sep 17, 2007 8:23 pm

came wityh new inserts... fitted fine...

headcoats · Post by **headcoats** » Thu Sep 20, 2007 8:40 pm

After checking my pistons on the calipers they all seem pitted on the ends

Now for stainless pistons and seals ,it's about £140 for the two calipers

Is it possible to get the old pistons re chromed like what they do with fork stanchions when they get pitted.
Is there a company that can do this ?

Charles · Post by **Charles** » Thu Sep 20, 2007 9:16 pm

Wouldn't it be cheaper/easier to get another pair of calipers that are in decent condition and don't need any work on the pistons?

headcoats · Post by **headcoats** » Tue Sep 25, 2007 5:39 pm

Can i use Dot 5 silicone brake fluid with the KR1S brake system ?

Charles · Post by **Charles** » Tue Sep 25, 2007 5:50 pm

I wouldn't, as DOT5 is silicone based and Kawasaki recommends polyethylene glycol based fluid DOT3. Dot 4 you can use.

mr_bungholeo · Post by **mr_bungholeo** » Tue Sep 25, 2007 6:36 pm

dot 5 is also very hygroscopic...it sucks up moisture like a sponge...you only need it in race bikes that get brake fluid changed every race...

headcoats · Post by **headcoats** » Wed Sep 26, 2007 7:37 am

So what's the correct brand and spec then peeps

I like silicone for the very fact it doesn't touch yer paint

Charles · Post by **Charles** » Wed Sep 26, 2007 7:44 am

headcoats wrote:So what's the correct brand and spec then peeps

Just take DOT 3 or 4 or 5.1. Don't know which brands in the UK are to be recommended....

flinty · Post by **flinty** » Wed Sep 26, 2007 6:56 pm

I've got all my pistons out (stirrup pump and an extra pair of hands to block up all the holes!) and they're basically all shagged. I can't bring myself to put any back in. I can't imagine that having these parts rechromed could be economic, what with machining and all.

I'm going to replace with original type rather than stainless as they originally use hard chromed to give better friction and wear.

I think I read somewhere that you have to be careful with DOT 5 fluid as it isn't compatible with all older types of seal materials.

headcoats · Post by **headcoats** » Wed Sep 26, 2007 9:16 pm

I contacted a firm about getting the pistons re chromed and they wanted £24.......EACH

Went to Cradley kawasaki yesterday and forked out nearly £60 for new seals

makes yer feel sorry for folks with 6 piston calipers

the-elf · Post by **the-elf** » Thu Sep 27, 2007 10:20 am

flinty wrote: I think I read somewhere that you have to be careful with DOT 5 fluid as it isn't compatible with all older types of seal materials.

Use 5.1 as that is compatable. The best fluid I've come across is Halfords own Brand 5.1.