Best way to improve brake feel

2468 Views 16 Replies 10 Participants Last post by Amac, Mar 1, 2009

cm8

Discussion Starter · Feb 28, 2009

I have a 2004 SV650 track bike and I am struggling quite a bit with brake feel. I have a bad tendency to lock up the front under heavy breaking and then can't really modulate it since the engagement start/finish is very short (and very close to the grip). I managed to lay down my bike today because I was under heavy braking (on a downhill portion of the track entering a turn) and then manage to miss a shift and with me trying to get everything straightened out, didn't match revs well and was essentially locked up in front and then had the rear kick out (since I don't have a slipper clutch and didn't match revs). End result - lowside.

Bike will be fine after a new right footpeg and bracket care of Woodcraft, but would like to get some opinions of how I can get a more progressive brake feel.

I run Vesrah RJL pads at this time. Forks are stock (with the upgraded valves). Also has stainless steel lines.

Any suggestions on what to try?

1 - 17 of 17 Posts

pne

· #2 · Feb 28, 2009

a new master cylinder for starters, are you running the stock unit? Why is it engaging close to the grip? The lever can be adjusted outwards.

cm8

Discussion Starter · #3 · Feb 28, 2009 (Edited)

pne said:
a new master cylinder for starters, are you running the stock unit? Why is it engaging close to the grip? The lever can be adjusted outwards.

What's a good source for Brembo M/C (if by new master cyclinder, that is what you mean). Is there a particular one that works best with the stock calipers/rotors? Also, any alternatives to Vesrah RJL pads for the track?

And yes - I have the stock MC

99Sv650N

· #4 · Feb 28, 2009

I have a hard time locking the front tire... My a$$ end always comes up first

SV650R

· #5 · Feb 28, 2009

I think an R1 (Brembo) master cylinder will help you... Or a late model radial GSXR Master cylinder... I would bleed the system with good brake fluid...

Sand blast the rotors and sand a little the pads... Then break in your new surfaces, 4-8 times at 35-40 mph... Let the rotors cool down... Then do it again, 4-8 times at 60-80mph... let them cool down...

You are set!!!

Luis

99Sv650N said:
I have a hard time locking the front tire... My a$$ end always comes up first

Do you need suspension work... Are you bottoming out your forks? Luis

cm8

Discussion Starter · #6 · Feb 28, 2009

The bike is a Superstock bike so I don't think I can replace the MC btw.

99Sv650N

· #7 · Feb 28, 2009

SVXR650 said:
Do you need suspension work... Are you bottoming out your forks? Luis

No I dont bottom out my forks, I dont however have performance front suspension. I just have heavier fork oil which seems to be a lot stiffer than stock. I can stoppie without bottoming out the front end.

pne

· #8 · Feb 28, 2009

talk to some of the other racers running sv650's, see if you can borrow a spare and see how it feels. The stock unit should be pretty progressive, which leads me believe something is wrong with your MC, or somehow one from another bike found its way onto yours. The bore and stroke of the MC will dictate the feel, effort, and travel of the brake lever.

SV650R

· #9 · Feb 28, 2009

cm8 said:
The bike is a Superstock bike so I don't think I can replace the MC btw.

I think you can bore them out...

What if you get an older 19mm non radial GSXR? ...They look about the same... ;D

Luis

SV650R

· #10 · Feb 28, 2009

99Sv650N said:
No I dont bottom out my forks, I dont however have performance front suspension. I just have heavier fork oil which seems to be a lot stiffer than stock. I can stoppie without bottoming out the front end.

Thicker oil only dampens more the springs.

It feels stiffer but it is not. You only restricting the movement.

You may not be bottoming out the springs... You may be hydro-locking them... :nana:

Springs absorb and relase force. Proper springs will resolve your issue.

Luis

636Tony

· #11 · Feb 28, 2009

depending on weight, your front fronts could be a big problem.

the stock brakes aren't great, but kris87 claims he uses a stock master, so i figure i can use it too.

do you still have stock springs? sounds like you might be packing up the front end if you do.

jdewkilla

· #12 · Feb 28, 2009

take it easy with kung-fu grip

Oh My Sack!

· #13 · Feb 28, 2009

Perhaps this doesn't apply in your situation but maybe someone else will benefit. I had brake fluid that had been in the reservoir for a few years. I think that's something often overlooked by many people. My brakes really felt crappy. The lever seamed creaky when squeezed and modulation was poor. I thought it was just something inherent with the SV, kind of like the sh!tty suspension we have on an OEM bike.

I took the Mighty Vac and drained and flushed both brake systems and refilled with Galfer Dot 4. The result was nearly as striking as the change to a new shock and Racetech Springs. I no longer thought I'd be needing to upgrade to a GSX-R master.

Old fluid has a yellowish tinge to it, fresh is virtually undetectable in the OEM reservoir. The yellow coloration is air and water as brake fluid is highly hygroscopic, it pulls moisture out of the air, hence the reason they say to always use a sealed, fresh bottle of brake fluid.

Invest in a Mighty Vac and change it. You'll be amazed.

See less See more

cm8

Discussion Starter · #14 · Feb 28, 2009

Thanks for the advice so far. It has occurred to me that I have not done a brake fluid flush since I bought the bike (and I don't really know when the last one was done so that was my mistake). I'll do that first.

andyauger

· #15 · Feb 28, 2009

Fluid is #1. I've had very good luck with the Valvoline Super Syn brake fluid.

Next would be to steel wool the pads and the rotors and clean all the parts with BraKleen or similar product. I prefer manual steel wooling to bead blasting the rotors, not to say bead blasting doesn't work.

If you could change the master cylinder one with a smaller bore would give you more travel/less effort which many find works well for finer control and modulation. On the other hand, a larger bore gives less travel/more effort which, guess what, many find works well for finer control and modulation.

SV_Marv

· #16 · Feb 28, 2009

+ to the fluid replacement references. Made a big difference in my brakes.

Amac

· #17 · Mar 1, 2009

SVXR650 said:
Thicker oil only dampens more the springs.

It feels stiffer but it is not. You only restricting the movement.

You may not be bottoming out the springs... You may be hydro-locking them... :nana:

Springs absorb and relase force. Proper springs will resolve your issue.

Luis

+1 to SVXR650's theory on the forks, especially how you describe your symptoms. Before I even got the end of your post I was wondering if it wasn't a suspension issue. Get your forks set up properly, that is the 1st money you should spend on a track/race bike anyway.

If you haven't serviced your stock m/c in a while, definately replace the fluid at a minimum. Like someone said, it works fine for Kris 87 - and he has won multiple NATIONAL championships on SVs.

Are Brembos better? yes, but provided it is working properly, the stock unit works more than well enough.

1 - 17 of 17 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.