Pop up brake upgrade.

[busatoon99]

As you may have seen in other posts the brakes on my pop up are kin shite. Its a standard caliper/master cylinder with braided stainless lines.
I stand to be corrected on this but ive owned a couple of rg500s in my past and the fork bottoms appear to be identical. Would a rg500 twinpot caliper bolt straight on or is there another better caliper that will bolt straight on to improve stopping power ?

Cheers

[fossie]

You will struggle to fit other brakes as the 16" front wheel leaves just enough room.
There isn't anything wrong with these brakes , if yours are grabby or weak , it is probably in need of a master cyl refurb, people forget tat brake fluid absorbs water in the form of condensation so bikes used rarely usually have diluted fluid.

The front brakes on these are the same as fittied to he rear of virtually all Suzuki up to and including the Hairybush.

[busatoon99]

Ok, that sounds fair enough and a bottle of brake fluid and a master cylinder kit is a lot cheaper than a pair of (rare) calipers. Should i use dot 3 or dot 4 for the brakes and clutch ?
If it does not work i would still like to investigate the rg500 caliper possibility as that also had a 16" front wheel, tho it was a different design. From what i remember the fork lowers had the same 4 way anti dive preload so presumibly the disc diamiter and caliper mountings where the same.

[Kryten]

Can't answer the question about the RG brakes but below is a comparison of the various DOT ratings of brake fluid.



Dry boiling point, Wet boiling point , Viscosity limit, Primary constituent.

DOT 2
190 °C (374 °F), 140 °C (284 °F), ? , Castor oil/alcohol.

DOT 3
205 °C (401 °F), 140 °C (284 °F), 1500 mm2/s, Glycol Ether.

DOT 4
230 °C (446 °F) , 155 °C (311 °F), 1800 mm2/s, Glycol Ether/Borate Ester.

DOT 5
260 °C (500 °F), 180 °C (356 °F), 900 mm2/s , Silicone.

DOT 5.1
260 °C (500 °F), 180 °C (356 °F), 900 mm2/s , Glycol Ether/Borate Ester.


Wet boiling point defined as 3.7% water by volume.

Brake fluids with different DOT ratings can not always be mixed. It must be of the same type, and at least the same rating. DOT 5.1 can replace DOT 4 and 3, DOT 4 can replace DOT 3. DOT 5 should not be mixed with any of these as mixing of glycol with silicone fluid may cause corrosion because of trapped moisture.

So DOT 5.1. 4 or 3 would work just as well. leave the DOT2 for the Austin Ruby, and only use DOT 5 from a completely new dry build.

Depending on the state of your master cylinder and calipers, I can recommend Past Parts Ltd to overhaul including a re-sleeve of the master cylinder. Not cheap, but I elected to use them on my SZ front master cylinder after I bu99ered up the bore by mistake replaced the little sight glass as well.

[Pop-Kat]

I got some Armstrong HH pads for the race kat for the last meeting, Although took a while to bed in they are the best available by far for the single piston Katana brakes, I just checked the application chart and they do the HH for the popup aswell as doing their C PRO pads which are the next level up, they are for hard road bike braking and track, they will be a softer compound but they could work well on the popup by providing some all important feel.

[busatoon99]

Top work there Kryton, i never knew there was so much to know about brake fluids. I will be going for a master cylinder and caliper rebuild with some nice new dot 3.
Pop-kat, i switched from standard suzuki pads to some ebc hh pads in my hayabusa and the difference was very noticeable. They gave a lot more initial bite and feel and i never noticed any fading at all. I dont know how long they lasted because i sold the bike not long after i installed the pads. Wether this braking improvement was because the hayabusa had 6 pot calipers, bigger and presumeably better discs, i dont know. For the sake of £40 or so it would be worth trying hh pads in the pop ups single piston set up before i go down the rg500 caliper route.
Thanks for the advice and info.

[Pop-Kat]

DOT 4 is the most commonly available, it's all I use in the workshop.

Popup's have twin opposed piston calipers earlier Kats were single piston

[busatoon99]

Pop kat, i sit corrected and i will use dot 4 as you recommend.

Thanks for the info.

[sparki]

.. in the pop ups single piston set up ...

thought pop ups had twin pistons on the front?