Rear Master Cylinder Swap

[nacs400ex]

I'm wondering if it is possible to swap out the 250r rear master cylinder oil cup with that of the 400ex. I like the idea of a screw on cap, rather then the screws holding on the cap. Seems a bit better, Also due to the fact that the 400ex's is $20CDN less.

I dont know if capacity/pressure would be a factor. Im just assuming it would work because some people switch calipers from either bikes.

[kyex40047]

No. The diameter of the 250r master cylinder tube is alot better then the 400ex tube, I was thinking the samething so I tried it and it didn't work.

[dynofox]

The 400ex caliper is only a single piston vs the 250r's dual. Seems like you'd be taking a step backward going to a 400ex unit.

Piston or bowl capacity has nothing to do with it working or not working.

All thats needed is a good seal at the hose connection, the 400 ex hose nipple is alot smaller, if you want to use that you can but you will have to use some electrical tape to make the nipple diameter wider and then push on the hose and clamp it down... if there is any leak what so ever you will not get the full breaking function.

[nacs400ex]

Originally posted by dynofox
The 400ex caliper is only a single piston vs the 250r's dual. Seems like you'd be taking a step backward going to a 400ex unit.

Im not trying to switch the calipers, I just want to know if the 400ex master cylinder bowl will fit with the rear 250r master cylinder.

[nacs400ex]

I guess I have to debate whether spending that $20 and having more of a hassle of taking it off is worth going with the 250R bowl.

Would there actually be a problem with it functioning properly with a 400ex bowl. Im not too concerned about making it seal tightly.

Anyone else try this before?

Originally posted by nacs400ex
I guess I have to debate whether spending that $20 and having more of a hassle of taking it off is worth going with the 250R bowl.

Would there actually be a problem with it functioning properly with a 400ex bowl. Im not too concerned about making it seal tightly.

Anyone else try this before?

Having it sealed properly is vital, thats how it works! break will not apply if there is no back pressure in the bowl. Its not simply a resevour.

And yes i have the same setup. if its not sealed tightly it will not work.

[nacs400ex]

Originally posted by DierWolf
Having it sealed properly is vital, thats how it works! break will not apply if there is no back pressure in the bowl. Its not simply a resevour.

And yes i have the same setup. if its not sealed tightly it will not work.

Thanks for the help DierWolf. I'll be sure to have it sealed properly to prevent any leaking. I just needed to know if it was doable.

I'll order up the 400ex master cylinder bowl tomorrow.

most welcome