Topic: Dual Disc Conversion Complete - Still Have Questions!

[jamracing]

Assembled everything, feel is great with the cbr1000 master cylinder! One thing remains odd - the adjuster bolt on the new caliper doesn't go as far as the other side, by a quite a bit. It's so loose that the spring isnt loaded, let alone room for the locking nut. Is this normal?




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[TjTalan]

The right side ear is further away then the left. I don’t know how this is usually accounted for.


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[TjTalan]

This is my bike, see the difference. Somebody will comment with more knowledge than I have. I would imagine it requires a longer bolt.



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[jamracing]

Hmm. I ordered a new oem bolt, didn't see an option for a longer one. Same for the spring.


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[TjTalan]

I’m going to be following in your footsteps here shortly, following.


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[jamracing]

I’m going to be following in your footsteps here shortly, following.


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Tips - get all angled banjo bolt end pieces with the short bolts... Also, make sure you're getting a master cylinder with the correct piston ratio (http://www.vintagebrake.com/mastercylinder.htm)
I reused the original junction block, and connected 2 17" lines and one 13" hose.


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[TjTalan]

Thanks for the Info!


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[Mark1976]

The fender bracket goes on top of the hanger bracket not in between the fork lower and hanger bracket.

[jamracing]

The fender bracket goes on top of the hanger bracket not in between the fork lower and hanger bracket.

I tried a few approaches -

• No spacer between bracket and fork causes binding
• With washers between bracket and fork causes binding
• With the fender bracket along with a washer added on one bolt eliminates binding

I'm willing to try other combos if you have specs

[Mark1976]

When you did your conversion, did you make any changes to the two lugs that the upper brake hanger bracket and fender mount to.

[Medyo Bastos]

When you did your conversion, did you make any changes to the two lugs that the upper brake hanger bracket and fender mount to.

Korreck


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[Mark1976]

You shorten the rear lug, is that correct.

[Medyo Bastos]

I would have to look at one to know for sure, but that does sound right.


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[jamracing]

You shorten the rear lug, is that correct.

First time I hear about shaving down the lug. Any numbers or pictures? If i shave it down, i'll need to add even more washers to top it from binding, won't it?

[seanbarney41]

Sounds like I set my extra caliper up similar to yours jamracing.  I had a similar problem with the adjuster, but I could just barely get the nut on a couple threads enough to snug down, probably only because I used pre-worn pads.  It didn't seem right to leave it like that.

I just left those adjusters out altogether on both sides.  All they do is make your caliper unfree to pivot to where it needs to be.   Bike rolls around much better now and brakes work better too.

[TjTalan]

You shorten the rear lug, is that correct.

First time I hear about shaving down the lug. Any numbers or pictures? If i shave it down, i'll need to add even more washers to top it from binding, won't it?

Read through this.


https://www.dotheton.com/index.php?threads/single-disk-to-dual-disk-brake-conversion-for-cb750.1525/


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[Mark1976]

If you're using one washer and its not binding then you have an alignment issue, disassemble it and look at the respective heights. Theres 2 ways to remedy this, If one lug is taller it'll have to be shorten equal to the other or as you have noticed, use a washer to build up the other.  Then mount the fender as I mentioned earlier. But try it without using the fender, you'll be able to see whether or not there's an alignment issue. The lock nut goes inboard.

[scottly]

I just left those adjusters out altogether on both sides. 

1+
The lower 8mm boss, or lug, on the right side fork lower is 3 mm higher than the boss on the left. The upper 6mm bosses are the same height on both sides. Since the rotor mounting surface on the right side of the hub is offset by 3mm, the lower boss will match the hub, while the uppers will need 3mm spacers, which will come from the fender brace. On the left side, the fender brace goes on top of the bracket, but on the right side the brace is sandwiched between the bracket and fork.

[PeWe]

Yamiya sell the needed longer version of adjuster screw with spring

[bryanj]

Inanswer to the original question yes that is how it is

[jamracing]

Haha, and I thought I finished the project!
Thanks for the input guys, i'll go back and look at the right forkleg lug height, and search for the longer Yamia adjuster bolt.


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[jamracing]

Sounds like I set my extra caliper up similar to yours jamracing.  I had a similar problem with the adjuster, but I could just barely get the nut on a couple threads enough to snug down, probably only because I used pre-worn pads.  It didn't seem right to leave it like that.

I just left those adjusters out altogether on both sides.  All they do is make your caliper unfree to pivot to where it needs to be.   Bike rolls around much better now and brakes work better too.

The reason for the adjuster bolt is to bring the pads as close to the rotor as possible. With a loose caliper, it'll impact the disc while riding, and push the pad in so theoretically it'll take a longer brake pull to activate the brakes.


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[Keith]

yamiya has a longer bolt and longer spring for this. You ran the stainless line to the outside? I would worry about catching something on it.

[jamracing]

yamiya has a longer bolt and longer spring for this. You ran the stainless line to the outside? I would worry about catching something on it.

Are they in the US? I only found a Japanese site.
If i move the fender back to the outside of the bracket, i'll jam the brake line inside the fork leg. If i snag anything on it, i'm already screwed...

[bryanj]

Nope they are japanese but sell world wide