Topic: looking for a mechanic NY

[suprafabs]

hey whats up guys, In the middle of doing a dual disc upgrade in my 76 CB750 and having some difficulties aligning the right pivot harm. after spending a lot of time and effort, I have decided to take it somewhere to get it done but i don't know any CB750 experts. If anyone has any recommendations of a mechanic near Long island  New York please let me know.

[calj737]

Do you mean the caliper mounting arm or the rear swing arm?

[Ericcb750]

Hey Suprafabs, The Forum members may be able to help buddy. Its hard to find guys who know these older bikes, especially well enough to know about dual disk conversions. I'm wondering if maybe some of the spacing is off? That or is the pivot arm mounted between the fender and the lower fork leg? I did that on mine and the pivot arm was at a bit of an angle. Once I moved the fender mounts to the inside, it lined up correctly....

should be fender...Pivot arm... fork leg.  Hope that's all it is. Good luck buddy.

[suprafabs]

I know its definitely alignment issue, I been trying adding washers here and there and slight better but haven't quiet got it yet. I have read in a previous post about someone shaving off some of the larger lower bolt on the lower fork but Im worries about shaving too much and end up with messed up forks!

if anyone has some good tips how to go about it, please PM

[Rookster]

Shave the bracket not the fork leg.  The bracket can be replaced pretty easily if you mess it up.  You have a 1976 CB750 so you should have the T shaped bracket.  There were several versions of this bracket for different bikes.  They look the same but the arms are different lengths.  Make sure your right side bracket is the same as you stock left side bracket.  Post some pics of what you have.

Scott

[DaveBarbier]

I really doubt a shop will be able to shave off the needed amount to make the dual disc work. I wouldn't trust them anyway.

You can shave the pivot bracket but you'll need to remove some material on the fork itself.

Check out my build thread for my dual disc conversion. I had a different method for seeing how much you need to remove from the fork which worked perfectly for me.

http://forums.sohc4.net/index.php?topic=140833.msg1698261#msg1698261

[scottly]

Post some pics of what you have.

Scott

1+ The front hub isn't symmetrical, and the right side rotor will sit about .125" more inboard than the stock left side, unless you have mounted the rotor on top of the speedometer drive. The lower mounting lug on the lower right fork leg sticks out about .095" more than the left side, so if the rotor is properly mounted, would theoretically require a .030" shim. The easiest way I know of to align the caliper is similar to what Dave linked. Remove or loosen the mounting bolts, and clamp the caliper firmly onto the rotor by squeezing the brake lever. Wiggle the caliper around until you find the place it wants to be with both pads flat against the rotor, and check the gaps so see where shims need to be added, or, if the mounting bracket is pressed hard up against a lug, material needs to be removed. It will also make a difference if you are using new or worn pads, as the pads wear at an angle. 

[suprafabs]

thanks for the pointers, Im going to try to give it another shoot over the weekend, really hope i get it, this job seemed so simple and is turning into a nightmare.....

thanks guys

[DaveBarbier]

Assuming the hub, spacers and disc carriages are all the same thickness in the 750's, could you try measuring the distance between the fork bosses and comparing them to someone's that has dual disc setup properly? In my mind that would give you the measurement goal and then you'd shave off the difference from the questionable fork.

[atm cycles]

There is a spacer/adapter out there that goes behind the speedo drive.

[suprafabs]

thanks for tips, Im a give it a shot myself once again at some point, keep you guys posted

[suprafabs]

Might be a stupid question but, if rim is slight bent, would it affect how the caliper /pad come into contact with the rotor?

[flybox1]

Focus on the vertical face of the brake pivot arm, and how it compares to the vertical face of the rotor
Once these are equal/parallel, then the brake pads will sit flush, and prevent the piston from locking in the caliper.
Some small straight edges will really help here.

[calj737]

Might be a stupid question but, if rim is slight bent, would it affect how the caliper /pad come into contact with the rotor?

No, the rim is positioned by the spokes, the rotor by the hub, the caliper by the fork leg. Same geography, different land countries...