YZMAN400

Member
Dec 2, 2003
2,491
0
Allright a question for the KTM Brain Truss

My 08 KTM300's front brakes feel like mush.

Ive noticed this a few times over the summer that they seem to go away. Twice now in wet conditions it seems like I had to double pump the front brakes to get some action. Normaly when this has happened in the past on other bikes that would mean a bent rotor pushing the pads away from the rotor. Not the case here. Rotor looks good. Ive seen bikes brakes in super wet conditions go away and have always attributed it to 1 the amount of water on everything and 2 maybe the water floating the pads away from the rotor (if that is even possible) But when I noticed this on the Pumpkin it wasn't anywhere near that wet out. I shouldn't have had problems like that.

I did the lazy mans blead the front brake by zip tieng the front brake lever and laying the bike way over so all the air rises up and out into the master cylinder. And that worked great for about 1 ride then it went right back to mushy.


Now I admit that I havent really investigated very hard as to why this is happening. I should check all the fitings change out the fluid with some good 5.1 motul fluid.

I guess I was just wondering if there is anything I need to know about the brakes on this like known glitches or something?

I replaced the front brake line on the kids YZ85 this summer with a goodridge line and bled them using the zip tie on the brake lever method and his brakes are awsome and have stayed that way. Honestly I was amazed at the front brakes on that bike. The feel at the lever is amazing. Made me realize just how mushy the KTM's front brakes were.

Any ideas?
 

duckboy

Member
Jan 9, 2005
200
0
I always had trouble bleeding my brakes until I started filling them from the caliper with a syringe.
 

BadgerMan

Mi. Trail Riders
Jan 1, 2001
2,479
10
In the rear, the cup washer in the master cylinder has a pretty short life. When it fails, the pedal gets mushy. I don't know if there is a similar part for the front.....never had a problem with the front brake.
 

YZMAN400

Member
Dec 2, 2003
2,491
0
BadgerMan said:
In the rear, the cup washer in the master cylinder has a pretty short life. When it fails, the pedal gets mushy. I don't know if there is a similar part for the front.....never had a problem with the front brake.


THATS what was sticking in my head just couldn't find the words. Cup washer. But thats just the rear huh? I remember Sndmn having issues with his which is why I was thinking there was something I was missing.

Well maybe Ill go thru and make sure everything is tight then change out the fluid with some good 5.1 and see where that gets me.

Really it feels like I have an air leak somewhere and its slowly letting air into the system. Like I was saying when I did the zip ty blead it worked killer for about a day then it was mush again like ait is getting in.

So I guess a good inspection and bleading is in order. Ill see where that gets me. I had one of those Mity micro vac pumps at one time that you can use to reverse blead the brakes from the bottom up. Those work very well IMO they are only like $35 so maybe Ill pick one of those up again (dont know where my other one dissapeared to) I have found that they work very well for bleading front brakes as you cant get the air to travel down the line, that whole air likes to float up in liquid thing.
 

bruno670

Member
Sep 13, 2006
394
0
I have had this problem since March when we bought the bike. I just keep bleeding them. Some of the problem "seems" to be going away. Can't really say for sure.
 

YZMAN400

Member
Dec 2, 2003
2,491
0
I remember Smit Dog (I think) posting up a link to some place that had some voo doo tricks they do on KTM brakes. Anyone know what that was? Not that this is what I need here I just happened to think of it and was curious as to what it was.
 

YZMAN400

Member
Dec 2, 2003
2,491
0
bruno670 said:
I have had this problem since March when we bought the bike. I just keep bleeding them. Some of the problem "seems" to be going away. Can't really say for sure.

Ahh so Im not the only one. Cmore says he hasn't had any issues with his.

Hmmmmmm

I think Im gonna ask Ron down at Lake Cycle Tuesday when I get back to work. Wander down there on my Lunch hour and have a chat to see what he knows.
 

bruno670

Member
Sep 13, 2006
394
0
TJ hasn't had any problems with his. I think that it is an early manu problem. Seems that the ones made after a certain date has no problem. Check to see what date yours was made, my guess is that it was an early problem. If so then getting a rebuild kit may just solve the problem.
 

YZMAN400

Member
Dec 2, 2003
2,491
0
bruno670 said:
TJ hasn't had any problems with his. I think that it is an early manu problem. Seems that the ones made after a certain date has no problem. Check to see what date yours was made, my guess is that it was an early problem. If so then getting a rebuild kit may just solve the problem.

Ya might be onto something there. Ill check into that.

How do I check the date on that anyway?? Vin # or is it in the manual somewhere on a sticker maybe?
 

YZMAN400

Member
Dec 2, 2003
2,491
0
Ok so a quick search on KTmtalk leads me to believe that this is not a totaly uncomon problem

http://ktmtalk.com/index.php?showtopic=318132&hl=front+brake

I am seeing others tell of the samy symptons as what I am seeing.

So far I havent found the cure. Although some seem to be switching to a Nissin front Master Cylinder with good results. I know where there may be a CRF450 master cylinder that I can try. Might be an option.
 

Fred T

Mi. Trail Riders
LIFETIME SPONSOR
Mar 23, 2001
5,272
2
The best results I have had is to reverse bleed the brake with a syringe and push the new Motoul 600 in. My quick trail side fix is to press my knee against the caliper and pump up the lever and do that 2-3 times and it's hard as a rock. They get air in them, even my 2009 does it.
 

09oneL

Mi. Trail Riders
Member
Dec 7, 2008
959
1
I had the same issue with my 07 300 - all I did was to change the fluid completely and problem was gone. It seamed the old fluid was cooked. I did this by bleeding until I was sure I had all the old fluid out.

The KTM (Brembo) brakes are the best brakes I have ever had

Fred B.
 

HeidiB

Member
Mar 7, 2006
52
0
The brake issue is fairly common. My easy fix was to rubberband the brake lever closed and let it sit overnight. The next day the problem dissappeared. It's quite strange and has happened a few times.
 

Wolverine423

~SPONSOR~
Oct 2, 2005
2,498
0
Talk with Ron as he has a fix for this prob. I just don't feel like typing a full page. Although a very good brake, I just don't think the Nissin is necessary.
 

duckboy

Member
Jan 9, 2005
200
0
I don't like the vacuum pump method it seems to vaporize or boil the brakefluid, like its pulling the solvents out of the oil. Also the new oils are extremely hydroscopic and leaving the oil exposed to the air isn't a good idea. Ideally buy a tiny bottle of fluid and change all of your brake and clutch fluids. Then toss the bottle. The polyesther oils are supposedly bad after two hours exposed to the air were the old mineral oils were good for months.
 

YZMAN400

Member
Dec 2, 2003
2,491
0
TCTrailrider said:
Ride slower, brakes become less of an issue. Mine work very good.

Ummm yea...try again...I couldn't even keep up with you last time we rode.
 

Wolf Child

Mi. Trail Riders
Member
Jan 30, 2005
644
0
brakes are for sissies! they only slow you down anyway.

rememeber me riding the snow chicken with no brakes?
 

SNDMN2

Member
Jul 18, 2003
343
0
Wolf Child said:
alzhiemers?

No . He's forty now. Slowly he"ll understand what us other middle age riders go through.

Selective memory disorder:
A condition where one can only recall whats important to oneself and not whats important to others.

I have it bad. Just ask whats her name. :ride:
 
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