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Offline nilsey

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dual disc question
« on: April 07, 2011, 09:47:39 PM »
i'm searching the archives but didn't see this one addressed: the disc cover on the rotor -- obviously you can keep the one on teh left hand side, but has anyone come up with a way of mounting the disc cover on the right hand (additional) rotor?

this would be on a 76 cb550k.
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1976 CB550K: stock airbox, cb650 cam swap, 4x2 exhaust, dual disc brake conversion.
1974 BMW R90/6

Offline Roach

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Re: dual disc question
« Reply #1 on: April 07, 2011, 09:56:17 PM »
IMO id chuck it in my parts box..the look of the duel disk is really clean without the cover.  8)
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Offline Don R

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Re: dual disc question
« Reply #2 on: April 07, 2011, 11:02:07 PM »
I made a right hand disc fender for my 750F. It took two lefts and some imigination.

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Offline mjstone

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Re: dual disc question
« Reply #3 on: April 08, 2011, 11:34:03 AM »
As far as I can tell, they never made one.  It would have to be a mirror image of the left one.  My '72 500 never had one.  When I did the dual disk thing I didn't bother with it.  Some say that shield is supposed  to keep water from spraying up at you in wet weather.  With my fairing it doesn't get to me, so big deal. ;)

MJ
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Offline Gman

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Re: dual disc question
« Reply #4 on: April 08, 2011, 03:35:35 PM »
I thought 2 wrongs don't make a right, but 3 lefts does.  However DonR seems to have shot that theory to pieces. ;)

DonR - Well done on the dual disc setup - looks sharp!  Do you notice a big difference in braking? 

Gman
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Offline mjstone

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Re: dual disc question
« Reply #5 on: April 08, 2011, 05:08:52 PM »
If you use a master cylinder that is designed for dual disks, then yes you will notice a tremendous difference.  You can use you original master cylinder, but you may not notice as much difference.  Brake lever travel will be significantly longer with an original master cylinder.

I have not had my disks cross drilled like DonR's.  I would expect he has much better performance in wet weather than I have.

MJ
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Offline Retro Rocket

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Re: dual disc question
« Reply #6 on: April 08, 2011, 07:45:49 PM »
Quote from: mjstone on April 08, 2011, 05:08:52 PM
If you use a master cylinder that is designed for dual disks, then yes you will notice a tremendous difference.  You can use you original master cylinder, but you may not notice as much difference.  Brake lever travel will be significantly longer with an original master cylinder.

I have not had my disks cross drilled like DonR's.  I would expect he has much better performance in wet weather than I have.

MJ

I have had piles of these bikes, all with dual discs and most with the original master cylinder, the brakes will be far better with twin discs, even with the stock master cylinder, and it really doesn't change the lever travel that much. Old rubber brake lines can make lever travel feel quite different, if you are doing this change consider braided brake lines, they will help lever travel quite a lot.... ;)
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Offline Don R

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Re: dual disc question
« Reply #7 on: April 08, 2011, 07:53:36 PM »
If you look closely you will see that I am still an imposter, the brake line is not hooked up yet. I have a deadline and a budget on my drag car. Oh, and sposnsors expecting to see the car in a parade soon! It the 750 bike tour hits here on parade weekend I've got a problem.
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Offline nilsey

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Re: dual disc question
« Reply #8 on: April 08, 2011, 08:26:06 PM »
Quote from: Don R on April 08, 2011, 07:53:36 PM
If you look closely you will see that I am still an imposter, the brake line is not hooked up yet. I have a deadline and a budget on my drag car. Oh, and sposnsors expecting to see the car in a parade soon! It the 750 bike tour hits here on parade weekend I've got a problem.

 ha ha i noticed that but didn't want to burst your bubble if you thought your braking had improved....

;-)
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1976 CB550K: stock airbox, cb650 cam swap, 4x2 exhaust, dual disc brake conversion.
1974 BMW R90/6

Offline Grnrngr

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Re: dual disc question
« Reply #9 on: April 08, 2011, 09:52:50 PM »
As I recall, it used to be common to turn the legs around and have the calipers on the back side, is there really any advantage?
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Offline Kong

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Re: dual disc question
« Reply #10 on: April 09, 2011, 05:34:05 AM »
There was a pretty good discussion about flipping the legs a couple of weeks ago, but the search function here isn't what it used to be and it might be difficult or impossible to find.

As I recall the consensus was that there is likely a minor improvement in handling caused by forces that are demonically complicated and difficult to understand, but for us laymen was summed up by saying it moved the center of gravity rearward and down somewhat that that was for the good.  I don't think its any more difficult to do the flip when you're doing a dual disk setup anyway and it may make brake line routing easier.  I'm interested in your progress because I've been putting off going out and doing it to my bike for about a month now.  My excuse has been that its too cold out, but its getting warmer every day now.  Gotta do something soon ....
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Offline Retro Rocket

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Re: dual disc question
« Reply #11 on: April 09, 2011, 05:44:12 AM »
If you spin the legs around and you want to leave the original front guard on {with the brace},  you must drill the rivets out of the guard and turn the brace around so everything mounts up properly...Can't remember what to do with the speedo drive but i am sure that needs modifying to work on the opposite side than it usually does.
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Offline Kong

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Re: dual disc question
« Reply #12 on: April 09, 2011, 07:30:32 AM »
Yeah, there is some part in the speedometer drive you have to grind down or leave out or bend some flaps on or something.  Whatever it is its no big deal and should be either obvious when you have the parts in front of you or easy enough to find out how to do by searching around here for a while.  There is also a fellow selling some sort of custom drive for this application on the For Sale  Forum that will take care of the problem for a fellow.

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2002 FXSTD/I  Softail Deuce
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1986 Honda Rebel, 450
1978 Honda CB550K
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Offline mjstone

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Re: dual disc question
« Reply #13 on: April 09, 2011, 08:55:53 AM »
Quote from: Kong on April 09, 2011, 07:30:32 AM
Yeah, there is some part in the speedometer drive you have to grind down or leave out or bend some flaps on or something.  Whatever it is its no big deal and should be either obvious when you have the parts in front of you or easy enough to find out how to do by searching around here for a while.  There is also a fellow selling some sort of custom drive for this application on the For Sale  Forum that will take care of the problem for a fellow.



Yes, rangelov has a speedo drive adapter that is machined out of aluminium  for dual disk setups.  He is also selling the longer bolts with the adapter if you need them.  Your original bolts that hold the disk on the wheel are not long enough to hold a second disk on. 

http://forums.sohc4.net/index.php?topic=76835.0

Another member, pampadori, makes excellent braided stainless steel brake lines.

http://forums.sohc4.net/index.php?topic=54790.0

MJ
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Offline Grnrngr

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Re: dual disc question
« Reply #14 on: April 09, 2011, 06:37:22 PM »
I bought one of Rangelov's devices, got an extra front wheel with disk and caliper, a GL master, and a pair of '74 legs, I think all I need now is lines and a tee. My 72 legs don't have the extra caliper mount holes, so I'll have to swap them. But, I've been thinking I wanted to have brother Joeyputt engrave "Honda" down the side of each leg, but I don't know what font I want, and haven't wanted to take the bike off the road to pull the disks and send them for drilling...but I want them before the ride,  but..but..and then there's the money thing, worked more hours and got less on my check. ?  ??   gotta go see HR...
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'72 CB750-K2 "PopCycle"
'73 CB750-K2 "Barney"
'77 CB750A   
'83 Virago 500 (red)
'83 Virago 500 (black)

"and so on and so on and scoobydoobydooby..oooooooshasha"  Sly Stone

Offline nilsey

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Re: dual disc question
« Reply #15 on: May 10, 2011, 08:08:49 PM »
Juts wanted to update you all with some pics of teh dual disc conversion.

I wound up using rangelovs' speedo drive plate, got some phenolic pistons from kevin hunter, sent my rotors out to thomas from  anubis cycle for drilling, got some brake lines from z1enterprises, and used an 80s kawasaki GPZ550 master cylinder.
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1976 CB550K: stock airbox, cb650 cam swap, 4x2 exhaust, dual disc brake conversion.
1974 BMW R90/6

Offline mjstone

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Re: dual disc question
« Reply #16 on: May 11, 2011, 07:54:21 AM »
Lookin' good! :D

Did you get the bolts from rangelov as well?

MJ
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1972 CB500Four (Honda)
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Offline nilsey

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Re: dual disc question
« Reply #17 on: May 11, 2011, 08:09:41 AM »
Quote from: mjstone on May 11, 2011, 07:54:21 AM
Lookin' good! :D

Did you get the bolts from rangelov as well?

MJ

Yup, got teh bolts from him too.
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1976 CB550K: stock airbox, cb650 cam swap, 4x2 exhaust, dual disc brake conversion.
1974 BMW R90/6
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