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dirty_jenny

yz450 adjust rear break?

11 posts in this topic

Forgive me if this in the search, I tried several searches by "rear break adjust", "adjust rear break" and couldnt find anything on it, except for moving the rear break position on a DRZ.

Anyway, how do I adjust the rear break strength? My rear break does not lock up unless I basically put all my weight on it. I bled them this weekend, that didnt do it. My son and my fast friends insist my rear break needs to lock up when I tell it to. More so, I dont think the stopping power is all that great and I have heard that I could adjust it, but cant figure out how. Oh, its a 2008 yz450.

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its hydraulic there is nothing external to adjust. maybe the pads are heavily glazed and worn? if the seals in your master are worn u will get a soft pedal. how does the pedal feel? make sure u dont have leaks around the piston in the caliper, also make sure the master itself isnt leaking. check brake hose for damage and ballooning. the rear wheel wont lock up in the dirt?

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It will help your search to spell brake the right way, but the only adjustment on the rear brake is for pedal position.

Assuming there's nothing amiss with the system itself, changing to a carbon steel rotor in place of the stock stainless unit will help. Might try a set of pads first, though.

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The pads are like new, but they are the stock ones. Are the stock pads crappy? There is nothing wrong with the system, the BRAKE (thanks Grey) works, it just doesnt lock up unless I lean my weight on it and push pretty far down on it. It stops the bike, I am having problems locking it up to make the bike slied / turn quicker, but between the new bars and this maxis tire its slides around pretty easy now. The 952 tire doesnt seem to turn as sharp as this maxis tire and I want to go back to that tire after i wear this tire out. Unless anyone else has a good suggestion for a tire that lasts a while and performs well.

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The pads are like new, but they are the stock ones. Are the stock pads crappy? There is nothing wrong with the system, the BRAKE (thanks Grey) works, it just doesnt lock up unless I lean my weight on it and push pretty far down on it. It stops the bike, I am having problems locking it up to make the bike slied / turn quicker, but between the new bars and this maxis tire its slides around pretty easy now. The 952 tire doesnt seem to turn as sharp as this maxis tire and I want to go back to that tire after i wear this tire out. Unless anyone else has a good suggestion for a tire that lasts a while and performs well.

several things here Jenny

your stock pads may be glazed - you can fix this with some 400 grit sandpaper - due to improper Brake Break - in

You may have air in the system - it is rather difficult to get all the air out - do a seach on bleeding brakes. The YZF rear brakeline is notorious for a certain area to hold that darn air bubble

Also adjust the pedal to the correct height - If it goes down more than 1.5 -2inches you have air in system

Rear brake sliding - I assume for woods or trails? Plz say yes

Tire choice - depends on the terrain - I use Michelin MS3s for my terrain in Ga a mixture of hardpack and loam and they work very well for me

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... improper Brake Break - in
Nice touch :thumbsup:
You may have air in the system - it is rather difficult to get all the air out ...The YZF rear brakeline is notorious for a certain area to hold that darn air bubble
That area is at the fitting where the line attaches to the master cylinder. It's a natural high spot with plenty of room for fluid to flow around a bubble without moving it. Crack that fitting open, push the pads back a short way with screwdriver, push the pedal down an inch, and tighten the fitting before releasing the pedal.

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Nice touch :thumbsup:

That area is at the fitting where the line attaches to the master cylinder. It's a natural high spot with plenty of room for fluid to flow around a bubble without moving it. Crack that fitting open, push the pads back a short way with screwdriver, push the pedal down an inch, and tighten the fitting before releasing the pedal.

Sounds easy enough. Am I supposed to top off the master cylinder? It looks to me like it has a fill line, one of my friends, who seems intelligent enough insists I should top it off then let what flows out come out when sticking the cover back on, doesnt sound right to me.

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It is actually right, though. Fill it to the point that the little bellows in the cover just starts to push fluid out as you replace it.

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Before tearing everything apart try simply cleaning your disc with some Brakleen.

When my '08 was new the front brake didn't work worth a dang and I was sure that I needed to bleed them even though (or maybe because) the bike was brand new. Also thought that it was perhaps the slightly newer-designed caliper and master cyclinder just was not as good as my '06.

Called a buddy of mine that went from an '06 to an '08 also and he said he had the same problem with the front brake. He simply cleaned the disc with Brakleen and 'viola' no more problem! Worked for me too.

Maybe Yamaha is getting some gom-boo on the discs that needs to be cleaned off.

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I replace the break lines front and back on my 06 yz450. I had the same problem after i was done bleeding the back; You got air in the line still. I did a gravity feed and pressing the back brake pedal. It took about 3 hours, good luck. they make tools that will do this a lot quicker.

try putting a clear hose on your back brake bleeder, crack the bleeder valve open and smash the back brake pedal down as fast and as hard as you can. If little air bubbles come out keep bleeding it you aren't done yet.

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I did a gravity feed and pressing the back brake pedal. It took about 3 hours, good luck. they make tools that will do this a lot quicker.
I did mine in 15 minutes without using any special tooling. The whole secret to the rear brake is the upward loop in the hose at at the M/C fitting.

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