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Been revitalizing the new-to-me '00 200, and decided to work on the brakes some. Got new (Chinese) brake pads on the front but noticed that I wasn't getting much stopping power. Today I replaced the brake fluid and bled the brakes...no change. I can grab the front brake as hard as I can and there is no danger of it locking up.

Is that normal for the KDX front brake, or should I dig in further to find the problem? Brake line looks like it is probably the original, so it probably needs replacing, but not sure if that would cause the brakes to be this weak. I recently did a front end swap and am using the front wheel and rotor off a KX 250. The KDX rotor that I am no longer using has a serious groove in it from the brake.

I decided to bleed the back brake while I was at it. Took of the reservoir top and guess what....bone dry. Filled and bled the back brake and it will lock the wheel up just fine now.

Thanks for any advice. We have quite a lot of hills around here and I tend to use my front brake a good bit...would like to have a little more bite to it.

Dig deeper. That front brake should be able to dump you if its working right. Maybe bad hose that's collapsed and not letting the pressure through, maybe caliper hanging, or maybe its the Chinese pads, but keep looking.

I doubt the stock line would cause that much trouble, unless it is leaking. Sounds to me like you still have air in there. These things are a real bear to bleed. Normally I have to remove mine from the bike, clamp the caliper up on something like a ladder, and hang the MC down below. Basically put the whole system upside down with the bleeder valve being the highest point. Pump, bleed, pump, bleed, pump, bleed and so on and so forth. The stock brake setup is not phenomenal, but you should be able to lock it up for sure. Cheap chinese pads certainly won't help the situation much.

keep bleedin, they are a real pain to get bubble free.. I usually end up doing jason's method. try try and try again, it can take a loooong time. I use syringes since I'm too cheap to get a mityvac, one of these days though...

I used the method in the service manual.....worked like a charm and very easy!

Julien D wrote:These things are a real bear to bleed.

+1000. Keep after it, and eventually it will come around.

Alright...I'll keep bleeding it. This is my first time to ever bleed brakes so I'm sure I probably quit to soon. I am bleeding them per the procedure laid out in the manual.

The front is a PITA compared to the rear. Make sure that the loop of brake line where it comes through the upper guide is below your MC, otherwise its an air trap and will be very difficult to get right. Easiest way is to put the bike on a stand to fully extend the forks and then pull the brake line down so that loop is gone and tape it to the fork to hold it until done. The front brake is powerful enough that I can do stoppies with it.

also please note you wont get an effective bleed or will take longer if the brake cylinder is not traveling freely within the bore of caliper. For example an older caliper I had was doing this and I did get it to bleed but took a while. Never got a good bite out of it. Just weak in the stopping department. I got a spare from a member here and also ordered a rebuild kit. I could immediately see with the other caliper how much it actually travelled to apply pressure. I could do stoppies with the new caliper *well used. I rebuilt my old one and put it on to see and with me cleaning the bore and putting the new seal and such It was now comparable if not a tad better imo of my replacement.

something to possibly check.

ICRage42 wrote:also please note you wont get an effective bleed or will take longer if the brake cylinder is not traveling freely within the bore of caliper. For example an older caliper I had was doing this and I did get it to bleed but took a while. Never got a good bite out of it. Just weak in the stopping department. I got a spare from a member here and also ordered a rebuild kit. I could immediately see with the other caliper how much it actually travelled to apply pressure. I could do stoppies with the new caliper *well used. I rebuilt my old one and put it on to see and with me cleaning the bore and putting the new seal and such It was now comparable if not a tad better imo of my replacement.

something to possibly check.

Good to know...I'm going to try bleeding it enough to get sufficient stopping power to ride this weekend, but based off my visual inspection of the brake I think it could probably use a rebuild, too. I have a spare brake front the KX 250 here, but it is missing some pieces, including the pistons so it won't be any help.

bufftester wrote:The front is a PITA compared to the rear. Make sure that the loop of brake line where it comes through the upper guide is below your MC, otherwise its an air trap and will be very difficult to get right. Easiest way is to put the bike on a stand to fully extend the forks and then pull the brake line down so that loop is gone and tape it to the fork to hold it until done. The front brake is powerful enough that I can do stoppies with it.

I'll give that a try....I know my loop is sticking up above the MC. Thanks for the heads up.

I recently replaced a front brake line....what a PITA...disconnected the master cyl from the bars so it was all vertical above the wheel cyl, still couldn't get enough flow....

Bought a mightyvac brake/vacuum kit, had it bled in just a few minutes.

I bled it some more, with the brake line pushed down so it was below the MC. All I saw coming out was clean, clear fluid with no bubbles. My guess is that I have a sticky piston in the caliper...

TN Dirtrider wrote:I bled it some more, with the brake line pushed down so it was below the MC. All I saw coming out was clean, clear fluid with no bubbles. My guess is that I have a sticky piston in the caliper...

not necessarily, bubble have a funny way to get stuck where u don't want them...

kawagumby wrote:Bought a mightyvac brake/vacuum kit, had it bled in just a few minutes.

+1 on that ...

You could also zip tie the brake level to the bar for a few days and the air should go to the MC. I did this on mine and it worked great. I know some KTM's require this.

ill also note to that

my not be stuck piston but the fact its not bled all the way. Best thing I found was to unroute it and then bleed.

hope this helps