Yz front -> rear brake conversion

[snacob14]

Does anyone have a write up on this? I've seen a few people on here that have done this conversion. Seems like a yz250 or 426 front brake will mount up to the rear brake system on a 250r?

[pdxbigfoot]

I got the idea from here http://www.exriders.com/vbb/showthread.php?s=&threadid=155875&perpage=13&pagenumber=3

Got ahold of jason86PRP250r and he pretty much talked me through it.
Its fairly straight forward and i was able get it done in about an hour.
You basically have to oval out the stock rear caliper mount bolt holes. I also had to do some filing to the inside of the caliper to get my wave rotor to clear. The side to side is really close.
I used the front caliper off a 2001 Yamaha YZ426F that got found on Ebay for $26.00 and it was in new shape.

Thanx to jason86PRP250r for the idea...now i wonder what else will fit.....hmmm..???
http://i238.photobucket.com/albums/ff145/pdxbigfoot/lucrica023.jpg
http://i238.photobucket.com/albums/ff145/pdxbigfoot/lucrica021.jpg
http://i238.photobucket.com/albums/ff145/pdxbigfoot/lucrica020.jpg

[snacob14]

So i"m using my stock brake stay, with the stock front caliper off of a yz. Do I need anything else, or is this it. What about brake lines, can I use my stock R line?

[pdxbigfoot]

Stock brake plate and YZ front caliper.Im pretty sure a stock line will work. I just had a custom one made at a local PDX shop just because,,,,good luck.

[SWIGIN]

my bother posted those pics in the link.... heres my pics

[SWIGIN]

master cly and bracket

[SWIGIN]

better pic

[superevil]

WOW i am so going to do that

[snacob14]

was the yz master cylinder necessary

[SWIGIN]

Originally posted by snacob14
was the yz master cylinder necessary



sure, if your tired of an old ugly 20 year old peice and trying to find rebuild parts.

this way its ready for 20 years plus i think it works better then the R unit.

but no, you dont need it

[snacob14]

got the brake today, it is so close to just bolting up, I had to grind a little on the mounting bracket. Do you guys widen both mounting holes on the brake stay, or just one?

[SWIGIN]

i did both, this way one hole isnt hoged way out.

[snacob14]

alright, got everything mounted, took about an hour. The problem I'm having now is the brake is real soft, won't stop the bike. All I have is DOT 3 fluid...is that the problem? DO I need DOT 4? I'm riding tomorrow so any help would be appreciated. I bled the brakes and it got me to where I am now...:macho

[pdxbigfoot]

A power bleeder??
If you dont have one most major parts stores will rent one to you for a small fee. If your not familiar with one it will basically pull the fluid from the cup to the caliper and is alot easier to remove all the air from the lines.
How are the pads?? New i would assume if not i would get some fresh ones in there..
Hows your master cylinder?? Does it need a rebuild or is it in good working order??
Thats about all i got...?? anybody else got any ideas??
Good luck man.

[snacob14]

brakes worked great before. I just don't think I"m done bleeding them. Its a pain, because I can't get my mastercylinder resevior open for hte rear. I have to bleed the rear with the brake resevior off and then put it back on when I"m done.

[snacob14]

any other suggestions? Has anyone had brake bleeding problems or spongy brakes with this swap. will brake fluid make a difference? I had dot three, but I just bought some dot 4

[Fear250r]

I think you need to get that cover off to properly bleed the brakes.

[g9901920]

drain all the old brake fluid because old brake fluid usually collects water..

[SWIGIN]

sorry man, the bleeder is lower then it should be, simply take the 2 mounting bolts out and let the caliper roll back (but still on the rotor) till the bleeder is the highest part.

air will come out and all will be right in the world....lol


you also could stand the bike up to bleed it as well if the master cly can get fluid in this position.

[snacob14]

awesome, totally makes sense now. I got hte master cylinder cover off finally with a little help from a dremel

[Rich250RRacer]

I looks like an OK conversion if in a pinch, but other than that it looks pieced together and rigged. For a little more money, the 450R rear conversion can be done easily and it looks FACTORY ORIGINAL.

[SWIGIN]

peiced together?

its cleaner then any quad caliper with a stupid block off plate...much cleaner looking

[Rich250RRacer]

Originally posted by SWIGIN
peiced together?

its cleaner then any quad caliper with a stupid block off plate...much cleaner looking

While it may be pricier at first, there are far more benefits to the 450R conversion than your conversion. With the 450R brakes you are using current, easily obtainable parts. An OEM 450R rotor is $34.50 through Service Honda, you can buy three of them for what it costs for one OEM rotor(if you can find one), or one quality aftermarket rotor. Pads are cheaper for a 450R. And you have the simplicity of changing the pads. I can have a 450R rear disassembled, pads replaced, and put back together before most guys can get the caliper pins out of a stock or YZ caliper. I'll take the factory look and a block off plate over something that was thrown together with old Yamaha parts. And it bleeds correctly.

I finally found the pics of the conversion. This is when it was first done. The crappy looking brake line has been replaced.

http://i228.photobucket.com/albums/ee108/rich250rracer/450rbk1.jpg
http://i228.photobucket.com/albums/ee108/rich250rracer/450rbk2.jpg
http://i228.photobucket.com/albums/ee108/rich250rracer/450rbk3-1.jpg

[SWIGIN]

thats the piont of this swap too, if you dont need/want to swap all that stuff.

i still think any quad caliper looks fat and ugly and unclean.

i will be going to a 450r rotor soon but i will keep my clean slim yz caliper.

[Rich250RRacer]

Originally posted by SWIGIN
thats the piont of this swap too, if you dont need/want to swap all that stuff.

i still think any quad caliper looks fat and ugly and unclean.

i will be going to a 450r rotor soon but i will keep my clean slim yz caliper.

You can't use the rotor without using the disc hub, which changes the position of the rotor in relation to the stock or YZ caliper. You need to use the caliper and the caliper plate from the 450R for everything to line up.

[SWIGIN]

now your boring me....i know all this and have it covered.

but i will not be changing my caliper bracket and i'll use a 450r anti fade.

[Rich250RRacer]

Originally posted by SWIGIN
now your boring me....i know all this and have it covered.

but i will not be changing my caliper bracket and i'll use a 450r anti fade.

So sorry to bore you. Just so you know, the 450R anti-fade won't help with positioning of the rotor. But you already knew that, right?

[SWIGIN]

yup, bin there done that

its realy not off enough to make a difference.

[snacob14]

rich quit being a pain. I did this swap for 30 bucks because I needed something cheap and effective. Now that I know how to bleed it I'm good. The caliper is off of an 07 yz450f. Is that current enough for you. i didn't have to buy a brake stay, I didn't have to buy a rotor. Its better than stock and cleaner looking. Done, don't need your comments if you are not talking about a yz caliper. By the way, bled it and it works awesome

[Rich250RRacer]

Originally posted by snacob14
rich quit being a pain. I did this swap for 30 bucks because I needed something cheap and effective. Now that I know how to bleed it I'm good. The caliper is off of an 07 yz450f. Is that current enough for you. i didn't have to buy a brake stay, I didn't have to buy a rotor. Its better than stock and cleaner looking. Done, don't need your comments if you are not talking about a yz caliper. By the way, bled it and it works awesome

I was just in one of those moods today.:D

[2fiftosR]

I have a YZ front caliper in good condition forsale if anyones interested?
$40 shipped

[woodsracer144]

Originally posted by SWIGIN
master cly and bracket what kind of kicker is that!?!

[SWIGIN]

Originally posted by woodsracer144
what kind of kicker is that!?!

350x....there were hybrids before yamaha made the 400-450 motors...lol

[snacob14]

alright, selling this whole setup now. z400 resevior, 250r slave, yz250f caliper, 75 bucks for the whole setup, i've also got a ceet racing desert seat foam and new seat gripper cover for sale 75 bucks shipped.