Front break and clutch

5 replies to this topic
  • Kasjok

Posted February 18, 2007 - 10:11 AM


I have to issues:

First, my front brake isn`t as sharp as I would like it to be. My friend has the same bike as I do (2004 yz450f) and he has great braking power right from the beginning of grabbing his front brake. But mine has like free movement at the beginning and then it`s starts to brake finally. By the way his brake pads are way more worn then mine. My pads are in a quite decent shape.

The second problem is with my clutch. Last owner of the bike had installed the hydraulic clutch system. Probably from some KTM. I have rode some bikes with a hydralic clutch on them, but mine is really hard to pull. It`s totaly rideable, but it feels like shizzle compared to my last bikes with cable clutch.

Thank you and try not to pay attention to my bad spelling. I am from Estonia( in Europe). :censored:

  • flintlock28

Posted February 18, 2007 - 12:53 PM


Sounds like you may have an issue with air in both the brake line and the hydraulic clutch.

I can't help you with the clutch....haven't used one yet, but I would get new brake fluid, and bleed the brake. The front brake is notorious for trapping air in the bottom loop (stock Yamaha has that strange curve to it).

There are ton's of posts about bleeding the front brake, but here is a short answer: (it's easier to do with a person to help you)

1) Squeeze the front brake lever several times, and hold it squeezed. Have your friend crack open the bleeder valve just enough to let fluid out....while you continue to keep it squeezed, until the lever touches the handlebar. Than have your friend close the valve, and you can now release the lever (REMEMBER, NEVER RELEASE THE LEVER, UNLESS THE BLEEDER VALVE IS CLOSED YOU'LL SUCK IN AIR)

Repeat this procedure a number of times (remember to keep the master cylinder with enough fluid in it, to keep from drawing air), until you have all new brake fluid in the're basically getting rid of the old fluid, and putting in the new fluid.

When you think you have all the old fluid out, do one more thing to give you a hard as possible brake lever.

1) leave the cover off the Master cylinder (to allow excess fluid to come out).
Take the front caliper off the bike, and use a C-clamp to push both Caliper piston's all the way back in. This will push any remaining air out the top to the master cylinder. Then slowly squeeze the brake lever a number of times to push the Caliper piston's back out, until they make contact with the may have to add more fluid to the Master cylinder. You should now have a very hard brake lever.

One last trick.....squeeze the brake lever and keep it squeezed. Than put a Zip-Ty or some other type of string or whatever, around the handlebar, to act as if you were holding the brake lever squeezed overnight. When you check it in the morning, you should find that the lever has gotten as hard as it's going to get.

I hope this helps....

  • Kasjok

Posted February 18, 2007 - 01:30 PM


Thanks for answering! I know how to bleed and I did it today. But only like 5 times and I didn`t get no air from bleeding. I think I better get the new fluid and hopefully it will make the difference.

About the clutch: I am thinking that maybe the last owner put one extra clutch plate into the basket, instead of getting the new ones. How do you feel? Is this possible?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • flintlock28

Posted February 18, 2007 - 01:42 PM


I have been told that the Magura Hydraulic clutches, don't give as light a pull as on the Yamaha YZ450f, as they do on other bikes. You said that it was maybe from a KTM, and they are either using the Magura, or a very similar model......I'm not as familiar with the hydraulic models, so I can't be sure.

I have been told that Motul brake fluid seems to work best for giving the best brake lever pull...make SURE that you push the Caliper piston's back in; it makes a big difference to giving a hard brake lever feel, and also do the Zip-Ty trick.

I don't know about the possibility of an extra clutch plate....maybe someone will chime in.

  • Kasjok

Posted February 18, 2007 - 02:07 PM


Did I get it right that I have to push caliper pistons all the way in and then pump them back to the brake disc and bleed?

And how is this trick with zip-ty working?

  • flintlock28

Posted February 18, 2007 - 04:28 PM


After you do the normal bleeding, leave the cover off the Master cylinder. Than remove the Caliper, and use a c-clamp to push both caliper piston's fully back in. This is because air gets trapped behind the caliper piston's (and the stock Yamaha brake line loop), and normal bleeding doesn't get it all out. You leave the Master cylinder cover off, because the fluid will be pushed up to the master cylinder, and overflow.

Once you do this, than just normally squeeze the brake lever several times to get the caliper piston's back against the rotor. You may have to add more brake fluid. Get the level set right, and than put the cover back on.

Once this is done you'll usually get about 95% of the air out.

Final step, squeeze the brake lever, put a Zip-Ty around the handlebar to keep the lever fully squeezed, and let it sit overnight. or for a day. Then cut off the Zip-Ty, and you should be as good as it's gonna get.

The two biggest things to getting a firm brake lever (on these Yamaha's) is pushing the caliper pistons all the way in, and also doing the Zip-Ty trick.

My understanding is that when the lever is compressed for a number of hours, it helps squeeze any tiny bubbles of air together, so that they form one larger bubble, and float to the top, into the Master cylinder.....all I can tell you is that it works.

Oh one last thing I remembered.....Baron VonBeard (another TT member) told me that when you're doing the normal bleeding, after you close the bleeder valve, and are letting the lever return to normal...let it "snap" back as quick as possible, don't let it back slow. I don't know why this helps, but he stated that he spent hours trying to get all the air out, and a mechanic told him this trick and it worked.

Related Content


2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies

Help with 2000 yz426 by weekend woods racer

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  36 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Need help by Goforaride

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  68 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.