Topic: Brakes - dual set up for front

[Dion]

Hi, I'm trying to convert my sohc 750 to dual Brakes up front. For some reason the RHS calliper sits skew on the fork. Any ideas?
 

[Tintop]

This is a common issue with this conversion.  Couple of threads on various fixes.  Mainly involving either shiming / modify the mounting posts / or modifying the pivot pin.  I used the last version on my 550, link to the build thread in my signature.  Or use the search function.

[Ewan 500K1]

adjuster screw tightened up tooooooooooooo much. On the RHS it shouldn't be screwed in any where near as far as on LHS. In fact there isn't usually enough of the bolt protrucing on the RHS to put the nut on. See photo of RHS attached, although this is on a 500.  Put your mudguard and wheel on and THEN see how your set up is looking before you start messing about with shims etc

[mitchie]

I did it  years ago with washers to shim it.

[K5 Keith]

I haven't done this myself but was planning to soon and have read many threads on it... I think this is were some even put the lock nut on the spring side of the adjuster.

[Tintop]

The issue is that the added (2nd) caliper holder does not sit square to the disk (about 2mm out).  Therefore the brake pads are at an angle to the disk and will not make proper contact.  There are three solutions - 1) shim the upper bolt boss / machine the lower boss / machine the pivot pin on one side.  I used the third option.

[mitchie]

The issue is that the added (2nd) caliper holder does not sit square to the disk (about 2mm out).  Therefore the brake pads are at an angle to the disk and will not make proper contact.  There are three solutions - 1) shim the upper bolt boss / machine the lower boss / machine the pivot pin on one side.  I used the third option.

Just shim out the whole bracket with one or two washers between it and the fork leg at each hole... I've done this with success.

[Ewan 500K1]

The issue is that the added (2nd) caliper holder does not sit square to the disk (about 2mm out).  Therefore the brake pads are at an angle to the disk and will not make proper contact.  There are three solutions - 1) shim the upper bolt boss / machine the lower boss / machine the pivot pin on one side.  I used the third option.

Just shim out the whole bracket with one or two washers between it and the fork leg at each hole... I've done this with success.

hold on ..... lets get back to basics ... the reason that the RHS caliper is skewed like it is in dbeerd's photo is that the adjuster screw is tighted up far too much on the RHS. Like K5 Keith says , the adjuster lock nut can be fitted on the inside of the caliper arm ... when stuff is squared up you'll find that there wont be enough thread protruding (if any) to put the RHS adjuster screw's locknut on the outside of the caliper arm.

The adjuster screws are only used to set the gap between the inner brake pad and the disc , that's all. ie JUST LEAVE THE ADJUSTER SCREWS & SPRINGS OFF UNTIL YOU HAVE THE WHEEL AN DISC IN PLACE  Forget about looking to square everytning up before you put a wheel, disc and mudguard on .

If not using a mudguard you will need to use shims between the fork leg and the caliper pivot mounting bracket ... if you are using a mudguard you may not need shims .... BUT YOU WONT KNOW UNTIL YOU PUT THE WHEEL AND DISC ON and see how the caliper squares up the the disc..... that what you need to test at this point in time.

You still with us dBeerd ?

[Powderman]

In the original pic of the 2 caliper assemblies it looks like the right side pivot bracket is different than the left one. If shims are needed I would disconnect the caliper bracket from the leg and put pressure to the caliper so it is held tight against the rotor and then measure what shims you need.