955 to 675 master cylinder conversion!

**Grubber** · 27th April 2011, 21:57

I am in the process of swapping my standard master cylinder on my 955i to a 675 radial m/c. It all looks very simple with a couple of minor adjustments here and there.
Just checking to see if there any little tips or tricks i may not have thought of that someone may be able to enlighten me on.

Thanks for any help.

**Taz** · 27th April 2011, 22:01

But why? .

**YellowDog** · 27th April 2011, 22:03

Originally Posted by Grubber

I am in the process of swapping my standard master cylinder on my 955i to a 675 radial m/c. It all looks very simple with a couple of minor adjustments here and there.
Just checking to see if there any little tips or tricks i may not have thought of that someone may be able to enlighten me on.

Thanks for any help.

You're a brave man

Best advice: Don't do it on your own

**bogan** · 27th April 2011, 22:05

You've probly already checked this, but make sure the calipers have the same piston area, otherwise feel will be a bit off. Also, bleed the fittings as well as the normal bleed nipple when you put fresh fluid into it. Radial masters look the business aye!

**Owl** · 28th April 2011, 07:22

I've just swapped my 14mm for a 5/8 axial. Certainly got the firmer lever I was after, but at the expense of bite/feel

Perhaps I should've taken the 675 radial route too?

**Grubber** · 28th April 2011, 09:02

Originally Posted by Taz

But why? .

Cause a day at the track and i got major brake fade. Been a bit of a problem to be fair!

Originally Posted by YellowDog

You're a brave man

Best advice: Don't do it on your own

Your not the first to say this. Have been told the are pretty damn good when all done. Has to be better than turn 1 at 180k's with no brakes.

Originally Posted by bogan

You've probly already checked this, but make sure the calipers have the same piston area, otherwise feel will be a bit off. Also, bleed the fittings as well as the normal bleed nipple when you put fresh fluid into it. Radial masters look the business aye!

Yup, got this sorted. They apparently match up really well. Suppose to eliminate any fade at all when the fluid gets hot. Should be good i hope.

Originally Posted by Owl

I've just swapped my 14mm for a 5/8 axial. Certainly got the firmer lever I was after, but at the expense of bite/feel

Perhaps I should've taken the 675 radial route too?

Was told this was another option but yes they bite real bad. Had a ride on one a couple of weeks ago that this had been done and have to say the feel was literally gone. They certainly stopped though.

**Grubber** · 28th April 2011, 09:05

Originally Posted by Owl

I've just swapped my 14mm for a 5/8 axial. Certainly got the firmer lever I was after, but at the expense of bite/feel

Perhaps I should've taken the 675 radial route too?

Will let you know if the radial has been a sucess.
New radial for 675 is around $650. Got mine for $390 just yesterday at AMPS. Last one of old stock.

**Owl** · 28th April 2011, 12:20

Originally Posted by Grubber

Will let you know if the radial has been a sucess.
New radial for 675 is around $650. Got mine for $390 just yesterday at AMPS. Last one of old stock.

Yes do that, as I'd be keen to know how you get on. The radial MC on mine would effectively make my brakes the same as the 675 Daytona, as they share the same calipers etc.

Ouch on the price

and I paid less than $200 for my replacement. Still, I'll see how I feel about it once I replace pads, clean pistons etc. I may end up back with the old MC yet.

**speedfish** · 29th April 2011, 09:51

yeah that should be good ive had the same issue on my 955 on the track another thing i was looking at was running 2 lines from mc 1 to each side to eliminate the hoop from right to left calipers which can hold trapped air .I was having a look at a late model speed triple and noticed that the 05 gsxr 600 beside it had the same mc so a second hand one of those could be a cheaper option for some

**Grubber** · 1st May 2011, 21:42

Originally Posted by speedfish

yeah that should be good ive had the same issue on my 955 on the track another thing i was looking at was running 2 lines from mc 1 to each side to eliminate the hoop from right to left calipers which can hold trapped air .I was having a look at a late model speed triple and noticed that the 05 gsxr 600 beside it had the same mc so a second hand one of those could be a cheaper option for some

I have already done the braided single lines and it did help a bit. A bit more feel in the lever after that. The GSXR 750 also fits apparently and works well. It's a 5/8 m/c and therefore allows for more power in the pull so to speak.
A couple of other tricks you can try is to back bleed as best you can and then tie your lever back to the handle bar with a cable tie as hard as you can and leave it overnight. This works really well in getting all the air out of the system and the feel is quite hard again after this.
Also another thing to do is take your calipers off and spray with brake clean and then push the pistons in and out fully a few times to make sure they are not sticking at all. This can be a common problem with these calipers. Chuck some brake clean on your floating rivets too so they don't stick. This can make your brakes vibrate if they are not cleaned from time to time.
That's all my advise for now.

**speedfish** · 4th May 2011, 19:26

yeah mate those brakes sure harden up in feel when you give the pistons a good clean up i used a tooth brush on the areas i could get to then i flossed the rest that you cant get the brush to with string soaked in brake clean i will now do this as routine maintenence

**speedfish** · 10th June 2011, 08:01

yeah cheers grubber i will do these mods later as my bikes pretty much become a track bike and can do with more efficient front stoppers thanks

**speedfish** · 20th July 2011, 13:12

Hey Grubber hows the bike now after the 675 m/c fitted? Ive got my race fairings on now and the m/c is the next job to tackle cheers Neil

**manxkiwi** · 26th July 2011, 13:07

Originally Posted by speedfish

yeah mate those brakes sure harden up in feel when you give the pistons a good clean up i used a tooth brush on the areas i could get to then i flossed the rest that you cant get the brush to with string soaked in brake clean i will now do this as routine maintenence

Something I always do nowadays is paint (with a wee model paint brush) a little silcone grease on the pistons when you're finished cleaning them. Keeps the seals nice and protects the pistons. They attract dust, but when you next clean them it just wipes off nice and easy.

Read it in a mag somwhere along the line, now do it to all my bikes. They do seem better for it too.

Cheers.

**DEATH_INC.** · 26th July 2011, 13:40

Originally Posted by Owl

The radial MC on mine would effectively make my brakes the same as the 675 Daytona, as they share the same calipers etc.

Doesn't the 675 run Nissin radial calipers?

I've noticed the 955 doesn't....therin probably lies the problem. Pretty hard for a master to cause fade, and by changing it you're only masking the problem, you'll still get fade, you just move more fluid so it isn't as noticeable. I'd be looking to see if any other calipers will fit (gsxr,r6 or suthin else that does work) rather than the master.

The early ZX10's had the same issue, and many 'fixed' it with a different master/braided lines/flash brake pads etc, but the real problem was the caliper, which when changed transforms the brakes like you wouldn't believe.

Of course I could be completely wrong