Upgrading the 1983 Rear master cylinder

[83gl1200]

dan filipi » Sat Aug 16, 2014 11:39 am[/url]":sy0v5o6i]
Just FYI it's been my intension all along to see how this $11 mc fits and if it's big enough to work on 83 linked brakes. Once I know this then ill buy a new Honda OEM.

Scratching my head on that one... You could have just started with a 1500 rear master off eBay and rebuilt that, rather than wasting time with something you have no intention of using. People have been using 1500 masters successfully for a while, there are a few threads out there on that subject. No need to try to go smaller or cheaper if you can already afford new Honda OEM. I don't get why you've gone down this path at all based on what you're saying now.

 

[dan filipi]

I like to try different things.
It's what I do.

 

[joedrum]

look theres a lot more to this mod than line fitting ...thats big but lets just see this through ...as stated it is a china mc and im sure pushing info like race is won in middle of race is not the way....i never told anyone that a 1000 stator works in a 1200 rotor ...till it did work

 

[Dusterdude]

Im fixin to buy one of these chinese mc for my 750,we'll see how it goes

 

[dan filipi]

It's mounted up.
This is no 1 hour job that's for sure.

Need a new reservoir hose then I can bleed it.

 

[Ansimp]

dan filipi » Sun Aug 17, 2014 9:25 am[/url]":1sf9c4yi]
It's mounted up.
This is no 1 hour job that's for sure.

Need a new reservoir hose then I can bleed it.

opcorn: opcorn: opcorn:

 

[dan filipi]

This MC is too small.
Even though the piston travel length is the same as the original, there isn't enough volume to push the 4 linked pistons.
I vacuum bled them and I'm certain there is no air.
It may work fine on a non linked brake system though but I'm on the hunt for an 1800 MC.
The 1200 and 1500 MC's look too big to fit, 1800 looks very similar to this one and uses a banjo.

 

[83gl1200]

dan filipi » Sun Aug 17, 2014 2:53 pm[/url]":22zma07p]
This MC is too small.
Even though the piston travel length is the same as the original, there isn't enough volume to push the 4 linked pistons.
I vacuum bled them and I'm certain there is no air.
It may work fine on a non linked brake system though but I'm on the hunt for an 1800 MC.
The 1200 and 1500 MC's look too big to fit, 1800 looks very similar to this one and uses a banjo.

Good to know, lucky I didn't try one.
I need to learn how to vaccuum bleed my brakes, did you run across any good directions or already knew how? I bought one of those mighty vac things and It didn't come with instructions....

 

[dan filipi]

Here's a basic video on the process.
I do the rear cylinder on the bike first since that's the one closest to the MC.

[video]https://www.youtube.com/watch?v=KTY2iBkFeV0[/video]

 

[dan filipi]

I went and ordered an 1800 rear mc, $38 shipped from Ebay.

 

[Steve83]

Should push plenty of fluid - 17.4mm piston.

 

[dan filipi]

That's good to know.

So what I've found out by doing this is the larger 83 mc is larger for a very good reason :mrgreen:

Oh well. Maybe by doing this I'll save others from trying it in the future and now I have a nice new braided line with the more common banjo end replacing the old one with chewed up fittings.

 

[83gl1200]

I probably would have tried one at some point, on one of my next bikes, so yes you saved me from making that mistake. Thanks
Sounds like that one would be OK for a single dual caliper piston but nothing bigger. I rebuilt my front master but still intend to replace it with something that looks better. Since on an 83 it runs only one dual caliper piston, would any average cheap china front master be OK? (Aside from not trusting cheap Chinese stuff, but nowadays everything comes from China...)

 

[dan filipi]

I can't remember who but someone here recently mentioned an aftermarket and cheap front MC that was adjustable.
Maybe it was ansimp?

 

[Ansimp]

The Chinese MC I had in the Rats Nest worked fine ( you must wonder why it came with a rebuild kit though) but I was down on brake pressure the same as with the original MC. Atm I am running an old CBR1000f MC ( had one handy) which has a smaller bore diameter (12.7mm) and adjustable lever position which gives me fairly good front brakes. I have ordered 82 dual piston calipers and discs which I beleive will give me better performance than my 81 set up. The final improvement would be to use new braided brake lines.

 

[dan filipi]

I suspect the rubber used in these cheap MC's are not very good quality, at least that's the case with the reservoir hose that came with this one. It split down the middle and I hadn't even installed it yet Lol.

 

[Steve83]

Hmmmm...bad Chinese rubber - no wonder there are so many people there!! :shock: :hihihi:

 

[Ansimp]

Steve83 » Mon Aug 18, 2014 11:40 am[/url]":124xes7y]
Hmmmm...bad Chinese rubber - no wonder there are so many people there!! :shock: :hihihi:

:smilie_happy: :clapping: :smilie_happy

 

[83gl1200]

dan filipi » Sun Aug 17, 2014 3:04 pm[/url]":10xz3rv9]
Here's a basic video on the process.
I do the rear cylinder on the bike first since that's the one closest to the MC.

[video]https://www.youtube.com/watch?v=KTY2iBkFeV0[/video]

Just had a chance to watch this, thanks, looks easy enough. But i was wondering about how he used Teflon tape on the bleed screws. Is that really OK, do you guys do that on motorcycles too? I watched another video that showed using grease to seal around the bleed screw, not sure which is better. I had one bleed screw break off already and I had to buy a new caliper, easy out couldn't get it, so concerned that Teflon tape might cook on the threads and make them hard to remove again since some comments on those videos say Teflon tape isn't meant for these high temperatures.

 

[dan filipi]

I don't use anything on the threads.
The idea here is to draw a vacuum at the nipple to pull fluid and air out of the line.
The bleeders seem to seal pretty good around the threads anyhow and what little air gets pulled in is going to go toward the pump, not into the brake line or caliper.