Front master cylinder

Buckydevil · Post by **Buckydevil** » 01:22 pm Sep 13 2015

My front brake lever was flapping around loose, only stopped going full 180 due to hitting hand guard,
Upon investigation I guess it should have an internal spring to push back near the pivot point
My old master really needs a service anyway but looking for info if I'd be better swapping to newer model master & lever if there is any improvement or is there a better alternative ??
What's the best option

Tioli · Post by **Tioli** » 02:33 am Sep 15 2015

I can't comment to much on the KDX master cylinder as my KDX resto turned into a hybrid before I got to ride it and sold the KDX master cylinder off.

Having said that I was not to happy with the feel of a 2001 KX master cylinder as I like a solid leaver. I ended up getting a braided line which helped some and have only now managed to get all the air out after several attempts to take the sponginess out of the system. I have blend many brakes and changed lines but this one took some work.

In my frustration I looked at many alternatives and noticed a few things:
Most Japanese master cylinders for trail and MX bikes seem to be Nissan.
MX bikes have 11mm boar as a smaller boar gives you more power, more feel but longer travel.
Trail bikes can be either 11mm or 14 odd, 1/2 inch larger boars give you less travel, feel and harder to pull.
Having said that my XR250 uses basically the same Nissan caliper as the KX and KDX it think and it has 1/2" boar and feels good with a braided line.

So it is problem not worth changing your master cylinder it the boar is smooth and fresh kit. For the most part they are all the same.

Hope this helps.

6 Riders · Post by **6 Riders** » 03:43 am Sep 15 2015

The KDX uses a Nissin 304 master cylinder. It is considered one of the best MCs available and still used on bikes today. Rebuild the one you have!
FYI MX MCs have a window, where the Trail MCs do not. I have both and prefer the one w/o the window.

Tioli · Post by **Tioli** » 03:01 am Sep 21 2015

How are the 304's with out a window better?

I thought I fixed my MX windowed 304 sponginess issue but it came back. I'm at a bit a loss as to how to make one solid. Are the non windowed ones batter?

6 Riders · Post by **6 Riders** » 06:18 am Sep 21 2015

I don't know what makes them better, just my personal experience.

Tioli · Post by **Tioli** » 06:48 am Sep 21 2015

Hmm, fair enough. I have to do something I just don't like spongy brakes they work well two fingers and all but to much travel for my liking

Edit
Just went to the bike shop to get some more smoke oil and felt every 304 in the shop all window versions. 5 new ones Kawasaki's and Suzukis and one KX in for service and they are all about the same and like mine so it's not the brakes.

Buckydevil · Post by **Buckydevil** » 02:05 pm Sep 29 2015

6 Riders wrote:The KDX uses a Nissin 304 master cylinder. It is considered one of the best MCs available and still used on bikes today. Rebuild the one you have!
FYI MX MCs have a window, where the Trail MCs do not. I have both and prefer the one w/o the window.

Big thanks for info on the KDX being a 304 Master cylinder
Problem with mine is that it was from a completely different bike
Now have the correct one on order.
Thanks for all input guys.

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