Topic: Questions about Dual Disc Conversion

[Chicago550]

Sorry if this has already been covered. I'm gathering parts together to put dual discs on my 75 CB550K and am wondering what additional parts I will need coming from a stock setup with ss line. I've read the conversion threads but the only parts list I could find was for the 750. Will I need spacers, longer bolts, that kind of thing? Some folks say the stock MC will still work, others cringe at the idea...

This is now my only bike and my goal is to have everything I need so that my bike's not sitting around. I would appreciate any input.

Thanks

[Bankerdanny]

The stock forks will work (I have a '77 also, but just the single disk) as both legs have the appropriate mounts.

I believe that the conversion instructions for the 550 should be essentially identical to the 750.

The hardest part is that the 550 uses a narrower rim than the 750, so you would need to get a 550 rim laced up to a dual disk hub. I believe that generally people recommend the hub from a 75-77 GL1000.

[chimmychong86]

You should check out this thread http://forums.sohc4.net/index.php?topic=76835.0 m the member is selling the plate and bolts which makes it super easy to make it into a dual disk. basically all you'd need is the caliper, rotor, break line, newer mc, and then you're good to go from what i understand.

[Chicago550]

Did some more digging and found the info I needed. Thanks for the link to that speedo plate. I might have to get one of those.

[crazypj]

The stock forks will work (I have a '77 also, but just the single disk) as both legs have the appropriate mounts.

I believe that the conversion instructions for the 550 should be essentially identical to the 750.

The hardest part is that the 550 uses a narrower rim than the 750, so you would need to get a 550 rim laced up to a dual disk hub. I believe that generally people recommend the hub from a 75-77 GL1000.

 
 I used stock hub on my 77-F without too many problems.
 You need to make sure caliper mounts are 'square' on fork leg, may need some filing or shimming.
 Get a master cyl from CB650 or similar dual disc bike
Yamaha work well as they use dual pistons on single caliper on 'early' models, replacement XS650 calipers are relatively cheap

[Chicago550]

Yeah, from what I've read the stock forks and wheel should work. I'm going to give it a try.

[Kong]

You'll need 6 longer rotor bolts, you'll need to modify the speedometer drive.  You can put a double banjo on the stock brake light switch and use two stainless lines, one down to each caliper. I believe just about any 5/8" or 17mm master cylinders will work just fine; many folks speak of using a Goldwing MC, most of them coming from E-bay.

[Chicago550]

Thanks Kong, I'm already looking into bolts, etc... I've heard of several different methods of doing this and noticed that many people are asking the same type of questions as me. So I started a new thread asking for people to post photos of what they've done. Afterall, a picture is worth a thousand words