Motorcycle Racing Forum

Motorcycle Racing => Wrenching => Topic started by: MightyDuc Racing on April 02, 2003, 12:02:33 PM

Title: Need Brake Help
Post by: MightyDuc Racing on April 02, 2003, 12:02:33 PM
A while back I posted that I was having a little problem with the front brakes on my Duc.  After every session I would come in and the front wheel would barely move because the brakes were dragging a bit.  We would clean the rotors with some brake cleaner and it would pretty much free itself up.  You all suggested I thoroughly clean the calipers/rotors/etc when I got home and maybe even put on new pads.  I did that and when I went back to the track (before my lovely motor issue) I had the same problem.  Any ideas as to why I seem to gum up my rotors in 6-8 laps that badly?  It's gotta be costing me some acceleration and speed due to the extra drag, though I can't feel it when riding, only when trying to clean the tire off and put on the warmers after the session.  Help!

TIA
Title: Re: Need Brake Help
Post by: cabbage996 on April 02, 2003, 12:06:44 PM
Every bike I've ever had has had a little drag on the front wheel.  The brakes always seem to drag a little.  Maybe try taking the pistons out of the brakes and cleaning them and replacing the seals and everything, change the fluid etc.
Title: Re: Need Brake Help
Post by: Dawn on April 02, 2003, 12:21:18 PM
QuoteIt's gotta be costing me some acceleration and speed due to the extra drag, though I can't feel it when riding, only when trying to clean the tire off and put on the warmers after the session.  Help!

TIA

You won't feel it during the heat of the race.  Just ask Paul.  On his ZX-6, the rear foot peg broke during a race (the bike tipped off the stand, but it looked ok  :-/).  When he came in from the race he realized that when the foot peg broke it activated the rear brake.  By the time he came in he boiled all the brake fluid out and melted the caliper (I still have the part to prove it).  It's a amazing we didn't fry the axle bearings.  

Dawn   :)
Title: Re: Need Brake Help
Post by: tzracer on April 02, 2003, 12:30:50 PM
A friend had a similar problem. His front brakes had significant drag (wheel would stop rotating immediately after we tried to spin the wheel). We tried everything. Problem turned out to be bent brake pads. Eventually trying pads from another manufacturer cleared up the problem.
Title: Re: Need Brake Help
Post by: MightyDuc Racing on April 02, 2003, 12:53:58 PM
I talked to Bruce from BCM about it and he suggested I remove the outer seal and machine tiny little air slots in the caliper and run Dunlop pads (???) and that is what all of his guys do.  I think I'll just stick with the cleaner for now...lol.
Title: Re: Need Brake Help
Post by: rsmith on April 02, 2003, 05:26:16 PM
Curious, what type of pads are you running?

I switched to Galfer pads last season because I got tired of fighting the drag issue with EBCs.

Title: Re: Need Brake Help
Post by: Bernie on April 02, 2003, 05:30:41 PM
I had a peculiar problem at Roebling last weekend that sounds similar to yours, but more extreme.

I got to turn 6 on my out lap of my very first session in Fridays practice.  Not even one full lap.  The front felt really wierd, like a flat tire.  I raised my left hand about 1 second before the front brakes locked and lowsided me. :'(

I'm no mechanic.  After speaking to quite a few people, it seems as though the "check valve" (or whatever that widget is in the master cylinder is that allows the pressure to release once the lever is released) may have been bad in my used master cylinder.  Each time I applied the brakes, they never fully released until they locked solid half a lap out.

In hindsight, I should have realized that all ws not right with that master cylinder.  I had a wicked hard time bleeding the brakes initially, and I had a really tough time spinning the front wheel when I got back from tech.  I've got a new master cylinder now, so we'll see how things work out.

During my inquiries to people who have some mechanical aptitude (unlike myself, a mechanical moron) the idea was floated that perhaps the seals in my calipers were bad.  The general consensus was that my result wouldn't have occured so quickly had caliper seals been the case.  Most people said that caliper seals would have likely taken several laps and a fair amount of heat to really start dragging severely.  Sounds kinda like your observations.

At any rate, I can fully testify that having your front brakes "on" when you don't want them to be (or intend them to be) sucks.  Definately do something, I doubt your problem will cure itself.

I have to thank the fellas behind me when I went sliding accross Roebling on Friday.  You guys did a great job on not running me over.  Thanks, and I apologize for causing the incident. :-/
Title: Re: Need Brake Help
Post by: MightyDuc Racing on April 02, 2003, 05:35:42 PM
I gotta try to track down some seals for this bike and change them.  Was planning on doing that anyways eventually.  Sorry to hear about your incident, and I hope you didn't hurt anything too badly.  

I am running the EBC HH pads.  Just bought a new spare set too....hate to just chuck 'em.  Hmm.
Title: Re: Need Brake Help
Post by: unforgivenracing on April 03, 2003, 01:58:30 PM
Have you blead the system ???
It may just be crap in the fluid.
Title: Re: Need Brake Help
Post by: Steviebee on April 06, 2003, 10:06:45 PM
I have the same thing with my front.  I cant spin the front tire ( well it spins but it stops when i stop turning it) , the brakes drag too much.  It makes putting on tire warmers more time consuming.  And have to be carefull taken them off, dont want to just pull the warmers off cause of the brake drag i dont want to break my new warmers.
I figured its just cause i just put new brakes on.   I've never shimmed the brakes but i read some where that you were supposed to do that.   (that might be for older bikes thou).   My rear will spin pretty easy but not my front ??

Hey im a road racer now !!!    yeaaaaa
Title: Re: Need Brake Help
Post by: FUBAR606 on April 08, 2003, 08:16:53 PM
QuoteI had a peculiar problem at Roebling last weekend that sounds similar to yours, but more extreme.

I got to turn 6 on my out lap of my very first session in Fridays practice.  Not even one full lap.  The front felt really wierd, like a flat tire.  I raised my left hand about 1 second before the front brakes locked and lowsided me. :'(

I'm no mechanic.  After speaking to quite a few people, it seems as though the "check valve" (or whatever that widget is in the master cylinder is that allows the pressure to release once the lever is released) may have been bad in my used master cylinder.  Each time I applied the brakes, they never fully released until they locked solid half a lap out.

In hindsight, I should have realized that all ws not right with that master cylinder.  I had a wicked hard time bleeding the brakes initially, and I had a really tough time spinning the front wheel when I got back from tech.  I've got a new master cylinder now, so we'll see how things work out.

During my inquiries to people who have some mechanical aptitude (unlike myself, a mechanical moron) the idea was floated that perhaps the seals in my calipers were bad.  The general consensus was that my result wouldn't have occured so quickly had caliper seals been the case.  Most people said that caliper seals would have likely taken several laps and a fair amount of heat to really start dragging severely.  Sounds kinda like your observations.

At any rate, I can fully testify that having your front brakes "on" when you don't want them to be (or intend them to be) sucks.  Definately do something, I doubt your problem will cure itself.

I have to thank the fellas behind me when I went sliding accross Roebling on Friday.  You guys did a great job on not running me over.  Thanks, and I apologize for causing the incident. :-/

Bernie,

I'm just glad you were ok, and (sort of) figured out what the problem is. Besides, your bike hitting me broadside just gave me that much more confidence at being at full lean and getting t-boned at being able to keep it up  ;)

If it is any consolation, I also got hit on the same side of the bike at the start of one of my Saturday races. Needless to say, I have bought stock in duct tape. And your tire marks simply give my warwagon character  ;D

Hope to see you (on two wheels this time) soon!
Title: Re: Need Brake Help
Post by: Bernie on April 08, 2003, 08:24:04 PM
Damn Steve!  Rough weekend.  I really did feel like a moron that day.  You were a very good sport about the whole thing.  I will be much more skeptical about used parts, and will never try and save money on sh1t like that again.  I definately owe you a beer or two! ;)
Title: Re: Need Brake Help
Post by: FUBAR606 on April 08, 2003, 08:25:45 PM
Folks,

I know this may not help fix your individual problems, but my front wheel spin will make you sick. I get pretty close to 20 rotations out of a hand spin.

My secret...I completely dismantle the calibers every 3 or 4 race weekends and THOROUGHLY clean them. I have never replaced any of the OEM parts. I remove any burrs from the pistons with steel wool and soak the dust and oil seals in fresh brake fluid and wipe each one down individually.

Then once installed, I ensure my wheel/rotors (which incidently float freely) are perfectly centered for maximum clearance. When changing tires I only remove/loosen the axle from one side so that the collar (the widget the axle tightens into) does not move thus ensuring the wheel is mounted back in the same spot before it was removed.

Feel free to take it for a spin if you are around me in the pits...it really will knock your socks off if you are into low friction.
Title: Re: Need Brake Help
Post by: FUBAR606 on April 08, 2003, 08:33:10 PM
QuoteDamn Steve!  Rough weekend.  I really did feel like a moron that day.  You were a very good sport about the whole thing.  I will be much more skeptical about used parts, and will never try and save money on sh1t like that again.  I definately owe you a beer or two! ;)

It was all good. Each contact incident just raised my level of confidence.

Don't feel like a moron at all...it is all part of racing and learning  :) You were really cool about it, which made me have the attitude I did.

I'll take you up on that beer at VIR this weekend. I'll be staying at the track and attending the awards banquet, so you have your chance  :D

I hope to see you there!
Title: Re: Need Brake Help
Post by: Bernie on April 08, 2003, 09:01:00 PM
I burned a coupla holes in my leathers (they're at Barnacle Bills) and am still waiting on a few parts, so I don't expect to be back in action until Summit, first weekend in May.  I'll have some cold brewskis for when I see you later this year at VIR or Savannah. ;)
Title: Re: Need Brake Help
Post by: Bernie on April 08, 2003, 09:05:03 PM
QuoteBesides, your bike hitting me broadside just gave me that much more confidence at being at full lean and getting t-boned at being able to keep it up  ;)

You know, that is really something, now that I think about it.  It would have been one thing if I had a reasonable bike, but my TL must weigh 5 million freaking pounds.  Pretty impressive on your part to stay on two wheels!! :o
Title: Re: Need Brake Help
Post by: FUBAR606 on April 09, 2003, 05:24:55 AM
QuoteYou know, that is really something, now that I think about it.  It would have been one thing if I had a reasonable bike, but my TL must weigh 5 million freaking pounds.  Pretty impressive on your part to stay on two wheels!! :o


The hidden training wheels helped treamendously  ;D ;D ;D ;D ;D
Title: Re: Need Brake Help
Post by: unforgivenracing on May 12, 2003, 03:51:21 PM
You know, a while back I menctioned something about race rotors, that you said "was'nt on your critical list."   ???Next time..