16 replies to this topic

[ryanthesailorman TT Bronze Member]

So I know that the kawi brakes are not the best but I just can't get it to stop dragging. It's driving me nuts. With the bike on the stand I can get maybe three rotations out of the front wheel if I spin it hard. I have taken it apart, cleaned the crap out of out and bled bled bled . Still dragging. it has new pads, new fluid.
What has worked for you guys?

I'm on somewhat of a budget and looking for a good fix. Id like to swap the whole system for a Hondas front brake buy that's to pricy I think.

Edited by ryanthesailorman, 08 May 2013 - 07:32 PM.

[dringer3888 TT Member]

Is your rotor warped or twisted? On my 2011 i can hear it dragging when i free spin as well. I think it's just how it is, it doesn't hurt anything. Have you taken your caliper off and spun your wheel to make sure your wheel bearings are good? Let me know if you swap for the Honda setup, i would like to know if it drags less

[PRYOUNG TT Member]

Not sure about the brake drag, not got the problem. When you spin the wheel, is the drag consistent for a complete revolution of the wheel?

If improved brake performance is your goal, a cheap fix is to replace the front master cylinder with a Brembo unit.

[ryanthesailorman TT Bronze Member]

dringer3888, on 09 May 2013 - 06:10 AM, said:

Is your rotor warped or twisted? On my 2011 i can hear it dragging when i free spin as well. I think it's just how it is, it doesn't hurt anything. Have you taken your caliper off and spun your wheel to make sure your wheel bearings are good? Let me know if you swap for the Honda setup, i would like to know if it drags less

rotor is not warped and the bearing are good.

PRYOUNG, on 09 May 2013 - 09:46 AM, said:

Not sure about the brake drag, not got the problem. When you spin the wheel, is the drag consistent for a complete revolution of the wheel? If improved brake performance is your goal, a cheap fix is to replace the front master cylinder with a Brembo unit.

the drag is consitent, it will make 2 revolutions and stop. if i compress the calipers the wheel spins free.

[numroe TT Addict]

Brake pad drag is often because the caliper piston fluid seal is sticking. Or maybe the dust seal is tight too. Did you pull the pistons out, smooth out the bore and put some brake assembly grease on the seals?

If that works but for a while but the problem comes back then you'll have to consider new seals. I've done that a few times on my KX.  Cost about $20. I've got the Honda caliper and master parts on my KX. It's a bit better for firmness and feel, but this problem can still happen with any make model caliper.

If you tried working on the caliper, but it did not work, then I'd suspect something wrong in your master. I've seen it happen on my son's KTM when the master piston is not retracting fully. Which can happen because of seal/bore roughness or because you've adjusted the push rod to be too loaded/long.

[ryanthesailorman TT Bronze Member]

I took it all apart again, everything looks pretty good. Im just going to regreece the seals and put it all back together. I did take the master cylinder apart this time, but everything looks normal in there too. no excessive ware or damage or anything. I'll let you all know if it works.

[PRYOUNG TT Member]

With the drag being consistent, it indicates that the disk is not bent. The only other issue I have experience with is piston stuck on the caliper, remedy as per numroe comments.

[ryanthesailorman TT Bronze Member]

ok , i took it all apart again, regresed everything, bled everything and swaped the positions that the pistons were in (not sure if this worked or not) the seals look good but there was some minor minor scraches on one of the pistons. i buffed it out. also in the master cylinder there is a little clear cap over the small lever piston, it has five small holes in it im assuming to regulate flow back into the MC. i heard somewhere that they are too small from the factory, so i took a dart (from a dart board) and widened the holes to increse flow. i put it all back together and bled and its a world of diffrence now. the wheel spins much more free now, i can get about 5 revolutions out of it plus the brakes feel better. before they seemed like they were either full on or full off but now if feels like there is progression at the lever, very minor drag and i havent sanded the rotor at all yet. what grain sandpaper should i get for this? also i used racing grease on the selas and pistons and MC (the same that i use for my linkage and bearings) is this bad?

[numroe TT Addict]

You must only use brake assembly grease on those seals. Else they can swell up and stick, again.

[ryanthesailorman TT Bronze Member]

so i have a new question, i have been playing around with how im bleeding the brake and im getting diffrent results each time. ill squeeze the lever and open the bleed valve up. if i squeeze the lever all the way to the bar the close off the valve the brake feels mushy and feels like it has too much lever pull to fully lock the brake howver the wheel spins much more freely. but when i only bleed the brake halfway to the bar and quickly close the valve while squezing the lever the brake is solid but draggs much more. is there a sweet spot that i need to find? i know the manual says the pull the lever all the way to the bar the close the valve but it feels weak when i do it this way. also how much do pretty new (4 or 5 rides) brake pads affect the drag and will it get better? thanks for the help guys.

[kx450f63 TT Gold Member]

ryanthesailorman, on 16 May 2013 - 09:45 AM, said:

so i have a new question, i have been playing around with how im bleeding the brake and im getting diffrent results each time. ill squeeze the lever and open the bleed valve up. if i squeeze the lever all the way to the bar the close off the valve the brake feels mushy and feels like it has too much lever pull to fully lock the brake howver the wheel spins much more freely. but when i only bleed the brake halfway to the bar and quickly close the valve while squezing the lever the brake is solid but draggs much more. is there a sweet spot that i need to find? i know the manual says the pull the lever all the way to the bar the close the valve but it feels weak when i do it this way. also how much do pretty new (4 or 5 rides) brake pads affect the drag and will it get better? thanks for the help guys.

I may have missed it, so I am going to ask anyway... have you cleaned and lubed the caliper mounting pins?

As far as the bleeding procedure goes... If you are getting different results using different bleeding procedures, that means you are letting air back in.  There are several ways to solve this.  You can attach a one way valve to the bleed port on the caliper, use a syringe to push fluid from the bottom to the top (obviously pushing all air with it) or learn how to use the lever and bleed port to not allow air back in during bleeding process.  Your bleeding procedure should not effect how much drag you are getting.

To answer your question about the pads and dragging issue... As long as the mount is square to the rotor (not bent or worn) the pads will not have any effect on the amount of drag you get, new or used.

An excessive friction issue in your type of brake system is only caused by a small number of things.  Bent rotor, bent or worn mounting assembly for caliper or pad pins, sticking caliper mounting hardware or pad hardware, sticking caliper pistons, failing brake hose (collapsing),  sticking master cylinder plunger (not returning to uncover the bleed port), miss adjusted operating lever (holding plunger in too far).  There could be many reasons for any one of these problems, but this is the basics.

[ryanthesailorman TT Bronze Member]

Thanks for all the help. i took it out last weekend and it feels smoother and less grabby which was fine but by the end of the day on a really rough track it was back to dragging. Now that it’s on the stand in my garage its back to feeling smooth and a more free spinning wheel. i bleed with a one way valve so i know there’s no air getting back in but the brake like doesn’t look new and i still question the caliper plungers and seals. i think the master cylinder is good. i took the lever off to ensure that it wasn’t slightly engaging the mc but i had the same results, a dragging front tire. When i compress the caliper slightly on the rotor the wheel spins for days but after a few lever grabs is slowed down. But its still better than i started with. Now im confused as to why it got worse over a day fo riding and got better on the stand  oh and i cleaned and greased all pins and brake pad guides. i think im just going to have to go thru a systematically replace one thing after another until its fixed.. Damn. ill start with the caliper plungers and seals first then brake line.

Edited by ryanthesailorman, Today, 08:08 AM.

[kx450f63 TT Gold Member]

ryanthesailorman, on 22 May 2013 - 08:06 AM, said:

Thanks for all the help. i took it out last weekend and it feels smoother and less grabby which was fine but by the end of the day on a really rough track it was back to dragging. Now that it’s on the stand in my garage its back to feeling smooth and a more free spinning wheel. i bleed with a one way valve so i know there’s no air getting back in but the brake like doesn’t look new and i still question the caliper plungers and seals. i think the master cylinder is good. i took the lever off to ensure that it wasn’t slightly engaging the mc but i had the same results, a dragging front tire. When i compress the caliper slightly on the rotor the wheel spins for days but after a few lever grabs is slowed down. But its still better than i started with. Now im confused as to why it got worse over a day fo riding and got better on the stand  oh and i cleaned and greased all pins and brake pad guides. i think im just going to have to go thru a systematically replace one thing after another until its fixed.. Damn. ill start with the caliper plungers and seals first then brake line.

No need to guess at it.  Take a wedge (screw driver) push the pistons in.  Be delicate, but put the wedge in between the pad and rotor.  Once the pistons are pushed in far enough to give you about an 1/8" gap or more between the pad and rotor, grab the caliper and wiggle it in all directions.  Notice how much play you have and where.  This may indicate you have a worn bore or pin.  The only way to fix this properly is to replace the caliper, bracket/pins, and bushings.  I have access to a machine shop so I bore mine and put inserts in the bore and bushings on the pins.
Once you have checked for wear, now see how well the caliper slides on the pins.  Push the caliper left and right (or in and out) basically slide the caliper on the pins as if you are mimicking the movement as the pads wear.  It should slide or glide with very little effort.
Most likely the problem is in your caliper mounting assembly.  It is rare to have piston issues in the caliper on a newer bike.  Also just as rare to have a hose issue unless it has previously been compromised, same with the master cylinder.
If I were going to guess at it, I would inspect the caliper assembly as stated and if no problems found I would start with the hose.  It is the least expensive.

[ryanthesailorman TT Bronze Member]

ill be doing this tonight. ill keep yall posted and thanks a ton for the help

[motogeek TT Bronze Member]

Ryan, have you tried clamping the brake lever closed and putting a zip ty on it overnight? This works for some guys and some of the street bike guys swear by it.

[ryanthesailorman TT Bronze Member]

motogeek, on 22 May 2013 - 04:48 PM, said:

Ryan, have you tried clamping the brake lever closed and putting a zip ty on it overnight? This works for some guys and some of the street bike guys swear by it.

I have tried it thanks thou. The confusing thing to me is how it got worse on the track but better on the stand. it seems if I grab a quick handful it's fine but if I use it progressively it tightens up and didn't want to fully disengage.

[ryanthesailorman TT Bronze Member]

I tried wiggling the caliper to see if there was any loose play in the pins. there seems to be more than normal, also the pens were a little bit dirty and didn't slide very easy. I took everything apart cleaned up and re greased it. when I had apart I pumped the brake lever to see how the calipers moves without the brake pads. one of them seem to be getting stuck after 1 or 2 lever pumps. the bottom caliber would fully extend but the top one wouldn't until I forceably stopped the bottom one from coming out. with both calipers fully extended and no brake pads I use brake cleaner and cleaned the hell out of the entire assembly. I regreased it and put everything back together and now it feels perfect and I get decent week spin. I'm guessing that I have a bad caliper plunger or bad seals.

Edited by ryanthesailorman, Today, 07:34 PM.