Hose Bolt Gaurd

The red circle is highlighting the brake hose bolt guard. We are developing a brake master cylinder with many adjustable features. One of the issues that will be solved on the new assembly is better protection for the pressure tube and hose bolt. Shown in this image is a test part to see how much abuse is thrown at the master cylinder. We ty-rapped it on Jeremy Martins’ bike at Millville in ’15 and were surprised to see how badly it got roosted in just two motos. After seeing the abuse, we decided to make it into a production part called the “bolt guard”.

If a rock impacts the bolt, the sealing washers can lose their seal and you have no front brake. The same issue happens when the bolt gets bent except then you will need a new master cylinder too since the threads may get trashed as well.

After two motos the guard had many small pits and scratches from sand and rocks in addition to being bent upwards. It looks like the part was tested at the right time since he won on the day and by the looks of this guard, it may have gone the other way without it! This product won’t win a race for you, it may keep you from losing.


There are two types of hoses most commonly found on master cylinders that have the hose on the front. The left image is the THIN style and is seen on current Yamahas. It has just the hose end with no protecting rubber insulator. The image on the right shows the WIDE style that is used on current Suzuki’s and Kawasaki’s. The large rubber insulator is how to tell them apart. Regardless of manufacturer, year or brand, just pick the THIN or WIDE guard that matches your brake hose.

Here is the THIN guard installed. A small gap between the guard and bolt seems to work better than being flush against the bolt. The guard is soft to absorb damage so it is easy to bend by hand to get the fit shown above.

The same applies for the WIDE guard. Make sure you use the supplied ty-raps since they are nylon and much tougher than the hardware store variety.