[Big Zero]

I have been having problems with the front brake dragging a lot especially after just sitting around. I thought it may be that the fluid is over-full. I looked down inside and there was a round disc with a rubber O-ring around it floating around inside the reservoir. The question is: which way does it go into the recessed hole in the bottom of the reservoir? It is dished out, do I put the dished side up or dish side down. Shold it be like a little dome down in there or a little cup? Could someone with a Yamaha unscrew the lid of their fluid reservoir and look down in there and let me know how the thing is supposed to go. I think it is the culprit that has been causing the brakes to hydro lock. It is OK while it is on the stand, but I am not too excited about having it lock at 75 plus in the middle of a fast left.

Any help would be greately appreciated. I know there are many guys with the old 426s on here that can help me out. I have a track day this Saturday, and I don't really want to crash right off the bat.

Thanks again

Paul G

 

[MotoMartin]

Yamaha of Troy have the parts list micro fiche images available on-line. Go to their web site and see if the schematic for the master cylinder is on there.
If not I'll take a look at my bike tonight (Pacific Time so it might be a little late for you.) I also have the workshop manual I'll check it out in there when I get home.

 

[MotoMartin]

The question is: which way does it go into the recessed hole in the bottom of the reservoir? It is dished out, do I put the dished side up or dish side down. Should it be like a little dome down in there or a little cup?

I took the cap off of my master cylinder and
it is a recess at the bottom, " a little cup" .
I hope that answers your question.

 

[SlowSlide]

Guys, for info on Yamaha parts, go to this page and click on your model in the menus at top. This is provided from Yamaha, and is very handy to view for just this scenario. Also it's good when you want to make a parts list to take to the dealer. You can just make a pick list, and print it, and hand it to the parts counter. :thumbup:

 

[Big Zero]

I have the service manual, but there is no indication of this part or the installation direction.

Motomartin answered my question, thanks.

Paul G

 

[crash790]

Brake drag is caused by 1 of 2 problems. A simple test will tell you which it is. When the brake is dragging.....crack the bleeder loose. If oil squirts out it is #1 If after releasing the pressure it still drags...it is #2 Since you have to remove a part of your braking system in either problem you might as well do both and be done with it.

#1: The bleed hole is clogged. In the bottom of the master cylinder there are 2 holes. The 1 that is closest to the brake line is the bleed hole. To clean it properly you will need to remove it and disassemble and clean it. I use 1 strand from an old throttle cable to poke threw the hole dislodging the debre. DO NOT do this with the assembly still together as you might poke a hole threw the seal.

#2: Your calliper is sticking. This is usually from a bike sitting and there is a corrosion under the seals in the calliper. You usually do not need any parts to fix this but simply disassemble and use a tiny welders 1-1 1/2 inch long wire brush to scrape clean the indentation the seal goes in and reassemble.