Hey guys.

I have a 4 months old RM250 2006 bike, I havent done anything to my brakes since I bought it (they were awesome new). Since then she's been on tough hill climbs, riding in the rain, through mud holes you name it!

Anyway, the brakes started getting really spongy. My brother is a mechanic and he bled them using them by using a tube over the hole over the bleed nipple and squeezing the lever etc. I watched him and only brake fluid came out (ie no bubbles).

Anyway, my brakes were still spongy!

I went to the shop I bought it from and felt the brakes on the new RM's (same as mine) and they felt very strong.

And the pads/disc looks fine.

Anyone got any ideas? I nearly crashed on the weekend because I couldnt stop in time - I made friends with some bushes.

what fluid did he use?

Also, get rid of those stock pads. Get some nice ones. Stockers are junk. Never liked them.

Also, he didn't bleed the brakes the best way (that way still leaves bubbles.

Empty ALL the fluid, get some fresh fluid (dot4), then do a reverse bleed of the system. You might as well take it to the shop they can do it for $30 in an hour. You need a reverse bleed tool. (like a pump).

Because you bleed from the caliper up, all the air MUST leave the system. Should make them as good as new.

Have you tried the "gently pry the front brake pads away from the rotor" trick yet?  Pushing in the wheel cylinders into the caliper forces brake fluid and air bubbles up into the reservoir providing a reverse bleeding effect.  Do this several times, pumping the brake lever inbetween.

Grizz, I know what the reverse bleed is but I dont have the large syringe needed to do it. I didnt think it would make that much difference.

Also, I am using fairly "kmart" variety dot4 fluid. Nothing fancy. And the stock pads worked well when it was new and arent anywhere near worn... so why should i need to replace them?

Is it normal for mud to be in the master cylinder? theres a little pouch thing in there that catches it, but it had a fairly large amount of muddy water up there!

I didnt want to bleed them from dry because it would take me 2 hours to level pump it full again!

To me the stockers never had the grip (but mine is an 03)

Reverse bleed will make a difference. As for muddy water, sounds like the fluid broke down or something in the lines or caliper started to desolve a little. If the fluid broke down then you must bleed from dry. Or the broke down fluid will still keep the line squishy.

I'm guessing the fluid looked really nasty?

mmmm it was either green or brown I cant remember. I will try bleed them properly again on the weekend.

It just pisses me off because I like to go fast and then STOP hard before the corners. and its quiet dangerous having spongy front... But the stockers were good on the 06! As good as my brothers CR. But the CR lasts longer.

Just buy a Mightvac vacuum pump.  Brake bleeding is a breeze, and you can always use it on the car, KTM clutchs, etc.  They are only about $35 or so, and it makes it super easy to change out your brake fluid, and you'll never have to deal with these problems.

i use a big syringe and bleed up... still i dont have that good of brakes (and this is with a braided steel line)... take it to the shop and give them the troubles

A syringe or mityvac is a good way of flushing/bleeding the brakes but remove the bleed nipple first, make sure it's clean and wrap PTFE tape around the threads before reinserting. This stops any air being bypassed via the threads when sucking the fluid through. It also stops mud etc. going down into the threads causing it to seize. I use this technique on road and offroad bikes and it works a treat. Sometimes, gently flicking the lever on the master cylinder will release air bubbles too!