2006 YZ 450F poor performing front brake

[renodirtandsnow]

I actually have two 2006 YZ 450F's that both front brakes have poor performance. No leaks on either system but the brake lever is very squishy and neither bike has good front brake stopping power. Is there a common issues with the 06's front brake? If not, what parts should I be looking at for the issues I am having?

[Pipefitter317]

I have an 09 that the front brake was weak on, I cleaned the pads with sand paper and the rotor with sand paper and this helped a ton. You might want to try that before ordering new parts.

[ROCKMOUNTAINTHUMPER]

I had same problem with mine on my 426 and then broke it, GrayRacer suggested a CR/CRF front master and it did wonders for my braking power.?

[renodirtandsnow]

Thanks for the input guys.....!!!

[Etown]

i have the same problem on my yz, it doesnt have the honda brake line routing though. i went to the yamaha dealer and felt some front brakes on some new bikes and even those felt squishy.

[Kasjok]

What years of honda master cylinders will fit to 08 / 09 YZ450F?

Would I have to then use Honda brake levers too?

[renodirtandsnow]

I took my caliper off one of the bike tonight and noticed one of the pistons did not move as well as the other. I was able to get both pistons out and cleaned them up and lubed them. So I will report back tomorrow if that has helped at all..... Seem like YZ's just make a week front brake system????

[JJRace]

They all use the same brand nissin parts. I am sure there is differences in the bore sizes and piston sizes, but they all work. If you get the newer 07+ CRF front master cylinders, you need the linkage type of lever also.

I have always found that ANY dirt gets between the lever and the piston where they make contact will not allow you to bleed the master cylinder properly. It traps air in there. ALso if you have an aftermarket lever like the ASV, you need to file it so it has about .002" clearance between the lever and piston contact.

[Adammoto]

I installed a stainless steel braided brake line (front only) on my 09 250F. That gave it a firm feel, and new pads gave improved stopping power. I would not recommend the Galfer/MSR line by the way because of poor fit. Try something else.

[grayracer513]

I took my caliper off ... I was able to get both pistons out and cleaned them up and lubed them.

Lubed them? With what?

[Ga426owner]

Get rid of the plastic brakelines they wear out and get too flexible. Get SS Braided lines as they do not flex, Flush all the fluids out and replace with new.

or buy a larger front brake kit(rotor, caliper guide and pads) and add the braided line and new fluid.

There is nothing wrong with the Master Cylinder unless it needs to be rebuilt

[Jim813]

I've experienced a much firmer feel at the lever after replacing the master cylinder on my 08 with the newer link-type( 2007 and newer) Honda master cylinder.

[grayracer513]

There is nothing wrong with the Master Cylinder unless it needs to be rebuilt

Perhaps not, but the '07+ CRF master has a different bore size, resulting in a different hydraulic ratio, and more braking power.

Personally, I've never had a complaint about my OEM set up.

[Ga426owner]

Perhaps not, but the '07+ CRF master has a different bore size, resulting in a different hydraulic ratio, and more braking power.

Personally, I've never had a complaint about my OEM set up.

ok bigger better and newer

but I don't have any complaints about my 06 oem master cylinder either...did swap out rotor, pads(Braking 270mm kit) and brakeline and now it is a 1 finger stoppy if you choose

[Wiz636]

The front brakes on the '06 are pretty good when in proper working order. Different story when they changed the front brakes in '08, they are not quite as strong as the '06front brakes.

[renodirtandsnow]

ALso if you have an aftermarket lever like the ASV, you need to file it so it has about .002" clearance between the lever and piston contact.

I do have ASV levers. But that is the first I have heard of having to clearance them....

[sic]

I bought the standard-sized Wave rotor for my '06 bike and it was no great improvement. This season, after suffering with a poor brake for so long, I just bought new, stock brake shoes and MAGIC, it was now a world class brake again.

Apparently, my pads had been oil contaminated for some time. You don't burn that stuff off. The pads gets ruined. Refresh if you ever leaked fork oil on that leg.

Sic...

[grayracer513]

I do have ASV levers. But that is the first I have heard of having to clearance them....

https://www.thumpertalk.com/forum/showthread.php?p=5844853#post5844853

[JJRace]

I do have ASV levers. But that is the first I have heard of having to clearance them....

Better spend a few minutes and inspect

[grayracer513]

The problem with ASV levers stems from people attempting to use the original Universal front brake lever (PN BLH01 for the C5 series) on an '07 or later YZ250F, '07 or later CRF250F/450F, or an '08 or later YZ450F master cylinder instead of the correct lever for that bike. The correct lever is BLH13 for the late YZ's and BLH15 for the late CRF's. Using the wrong lever can cause the master cylinder piston to be depressed far enough that it won't allow fluid to flow back up into the reservoir as it heats, resulting in a self locked brake.

Since the master cylinder is where the difference is, I would imagine this same thing would apply to any lever, including OEM.