07-09 Speedmaster questions

I upgraded my front caliper to a pretexh six pot- factory Bonneville (2007) master cylinder has an 11mm bore and doesn’t push enough fluid, imo, to the break.
So i would like to replace it with a Speedmaster Master cylinder (which has a 13mm bore- i am under the impression, via ordering diagrams, that the handlebars for a SM come 1” stock. Can any one verify this??
Also, are the wiring harnesses the same for the controls? I believe i can just use my old cluster, but if i must swap it out...




Staff member
I did this master cylinder upgrade on my 2008 Bonneville when I upgraded to the Brembo front disc brake. There was a slight improvement. And yes, these were designed for 1" bars. The connections from the wiring control harness are identical.


Staff member
The upgrade to the larger 13mm bore master cylinder (from the America or Speedmaster) is literally a replacement of one Triumph part with another. Everything else stays exactly the same... wires, levers, etc. The two parts appear the same on the outside because they are - only the inside bore dia. is different. The upgrade does produce a slightly firmer front brake feel which is an improvement. However, if you really want a radical change, I recommend replacing the entire front brake system with the Beringer Brakes master cylinder, lever, caliper, and rotor. OMG, what a difference! I can now control my Bonneville with one finger on the brake, it is that good! You can purchase the entire Beringer Kit through Bonneville Performance - https://bonnevilleperformance.com/product/beringer-front-brake-4-piston-caliper/ - https://bonnevilleperformance.com/product/beringer-front-brake-full-floating-rotor/ - https://bonnevilleperformance.com/product/beringer-radial-brake-master-cylinders-levers/ - https://bonnevilleperformance.com/product/beringer-clutch-levers/ - https://bonnevilleperformance.com/product/beringer-clutch-and-brake-switch-kit/


That’s a nice set up! Are those thruxton controls?? I was contemplating a switch if possible.
I’m running a free float EBC , with a 6 pot pretech - and definitely need more fluid,


Staff member
The electric controls and switches are from later model Bonneville's that use the 7/8" bars and separate master cylinders. I had to sand the center holes to fit 1" bars... there is enough extra plastic that it can be done. I also had to do some minor wire splicing to use the Beringer clutch and brake switches instead of the Triumph ones. All-in-all it worked out well.
I picked up a 2007 Speedmaster mastercykinder: new through B.B.-
Drastic difference on my 6 pot caliper campairsd to stock ! For the money can’t beat it- if i redo the controls i kill upgrade them for sure