Alright, newbie to the forum, though I have been really appreciating all the great advice in the 2 years I've owned this little goat. 2006 XT225 is my HS son's ride, and it has really served us well for 700 miles of dirt road rocks and rides so far. Posting this in case someone else has the same problem and can benefit.

I bought this 2 years ago, tidied up a few things on it, but the last owner barely rode this fine machine, only had 1900 miles in 10 years! Rode great until 2 weekends ago, when we got all muddy on a nice ride to Young, AZ. When I got back, as we've done many times before, we let it cool, then hosed off both bikes with a very low pressure garden hose and brush, I usually avoid as much of the engine area as I can, and let it dry off. Since we have no garage there, I load it into my covered tiny trailer and head back down to Phoenix.

This past weekend, the front brake was nearly locked when I tried to pull it out of the trailer. I pulled off the cylinder housing, cleaned off the crud from the cylinders (quite a bit) and got them pumping smoothly again at night, hoping that did the trick, and next morning gave it a test ride - as it heated up, it locked up again. So, we parked and passed up my son's last ride before college, unfortunately.

Tonight, we bought a vacuum pump from Harbor Freight for $25 and drained the old fluid from the bottom, carefully filling with new fluid from the top as son pumped vacuum and I pumped brake lever. Took about 15 minutes, careful to never let air in the top line. Old fluid was like a dark beer color, not Guinness, but an amber ale. New fluid like mich Ultra. Once done and the top back on, brake pedal is CONSIDERABLY more soft, but she doesn't lock the brake at all until pedal is pulled, then stops in her tracks.

Tomorrow I'll give her a test run, but so far she feels good! So you more experienced riders and mechanics, did I get water in the reservoir or the line somehow when I washed her? Still has plenty of pad left, and the master cyl feels like it's great once again with new fluid, anything else I need to think about? Thanks so much for all the great advice shared on this site, it has been a godsend!

If I recall, there are guide pins on the caliber with rubber boots. These should be clean and smooth less any pits from rust. You can spin them in a drill and use sandpaper if required to resurface. Special caliber grease is available from auto parts stores. Make sure the boots are not cracked.

The diagram is HERE. Parts I'm referring to are annotated as #6 & 7. Refurbishing this part of the caliber should be attended to. Good luck!

Yes, I recall these 2 pins and boots, I believe they were relatively clean, but then I was looking at them with a flashlight on that first night, when I cleaned off the cylinders. It was interesting that they were designed to keep the calipers free playing somewhat to adjust to the pads.

That's an easy job, I will do that today before I take it out on the test ride.
Thanks for the reminder, and the diagram!

U R Welcome. A caliper can "stick/hang" on those pins as it floats over the rotor. Not necessarily a locked brake but drag, perhaps. Obviously, there are safety concerns here if a front wheel locks up or suddenly drags excessively.

We had repeated problems with the rear drum brake when it got wet and infiltrated with silt. It would lock tight which required lifting up on the brake lever to unlock it. Not always convenient when trail riding.

The XT225 is a highly reliable bike. Albeit with some quirks and weak areas one needs to work through. Probably everything along those lines has been documented here somewhere. Ride safely and enjoy.

Update: I did take off the caliper and cleaned off the old pins, they weren't all that dirty. Copiously applied brake grease to the pins, used a qtip to put some all around the cylinder with a thin layer, kinda scared to goop too much on there as it will collect dirt, but I suppose any amount will collect dirt.

Re-installed the caliper, tested the brake, then went for a 10 mile easy ride down side streets, testing the front brake stopping often to see if front would lock up. Worked like an absolute champ, stopped on a dime, then freed up right away, no lockups

I'm pretty sure some water or dirt had gotten into the line, but I've always heard that caused the brake to NOT work, not for it to expand and clamp the brake ON. I'm not gonna overthink it, but certainly am gonna change the brake fluid on my other bikes as soon as it cools off here in Phx.

Thx for the head's up on the rear brake, we haven't had that problem, but will file it away for when we do!

Is the dust seal intact?

https://www.ebay.com/itm/Yamaha-XT-225-Serow-front-brake-caliper-seal-kit-2002-2003-2004-2005-2006-Serrow/181362718741?hash=item2a3a0f7815:g:n-YAAOSwxH1UIuBN

Flushing brake fluid should be on the annual maintenance list, along with greasing the suspension, checking the wheel and head bearings for movement, clutch cable inspection, and brake hose inspection.

Your rear brake will likely be fine given the dry riding climate you're in. Moisture, mud and silt were the cause in our case.



The photo above was very typical of what promoted rear brake issues. Lots of silt and glop in the stream bed. Creek crossings in relatively clean water wouldn't have been an issue IMHO.

The drum diameter also increased due to wear which didn't help. It's the iron sleeve inside the hub that gets ground away. The brake design doesn't include primary/secondary shoes either.

Wow, that is a pretty awesome pic crossing that creek! Yes, here with the drought we (and you in colorado) have been in, these kinds of crossings are rare, and especially dangerous actually with flash flooding common. Unfortunaey for me, i never rode dirtbikes when i grew up in Monte Vista and Ft Collins CO, as there are so many epic rides in that state!

By the way, agree with changing brake fluid annually, now that i know how dead simple it is to suction from the bottom with that tool, but how would i inspect the front brake hose?? How does that part fail?

Just look at the brake hose for cracks in the outer cover where it flexes or abrasions where it rubs against something.