Wrong brake lever or broken master cylinder?

3 replies to this topic
  • RWYZ450F

Posted October 19, 2010 - 04:41 AM


I'm on an 08 yz450f. Had a bad wreck in practice and broke both levers. I went to a vendor there and all he had was an 07 yz250f set of levers. He said they were the same. They looked similar so I took them. They fit but after I rode around for a bit, my front brake locked up. Once I took the brake lever off, the brake unlocked. Is it the lever or did I jack up the master cylinder? The pin that the lever contacts with hangs freely but seems to compress the brake properly. I never paid attention to how the pin functions before so I'm not sure if that's normal. I ended up running the race with no front brake.

Any help would be nice.

  • grayracer513

Posted October 19, 2010 - 06:50 AM


The '07 YZ250F lever should have worked, but it may not have been the correct one for that bike either. The brake locked because the lever fit incorrectly, pushing the piston in farther than the fill port in the master cylinder. Then, when the fluid heats up, it can't escape to the reservoir, and applies the brake instead.

The lever is wrong, simple as that. Compare with the original one at the point where it contacts the piston. You'll see what I mean.


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

Posted October 19, 2010 - 06:40 PM


Get yourself some bendy levers!

  • osheen

Posted October 20, 2010 - 11:58 AM


I've seen several times an aftermarket lever do what is happening here. The levers are real close and fit but need to be filed down to allow piston to retract all the way as Gray has stated. This sometimes happens even if the lever is supposed to be an exact fit for the particular bike. This is one of those things that really gripes me about aftermarket stuff. A lot of it does not fit and work as good as OEM....

Related Content


Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

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.