Topic: 1978 cb550 dual disk problem / HOW TO

[Honda550k]

Hello everyone. I'm in the middle of doing the dual disk conversion. I have Googled every possible problems people have came across when doing the conversion. The 750 is covered but i did not find any info for the 550.

My problem is that my front wheel axle won't align with the forks.

I don't plan on running the calipers behind the forks because my front Fender has a mount behind the forks.

Here's what I have on the axle from left to right:

Axle nut. Spacer that going in the bearing. The bearing. The stock disk brake. wheel. The bearing. The second disk brake. speedo gear. Speedo drive. Axle.

I did not grind my speedo drive as I am just following this instructions.
http://www.salocal.com/sohc/tech/dual_disks/dual_disks.htm

I thought it would be the same for the 550. But I'm still scratching my head as to why my wheel won't mount into place even with the calipers off.

Thanks a lot!!!

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Bottom of page 1 is the HOW TO

[dave500]

that nut is on the correct way around?and on the left side of the bike?

[Honda550k]

that nut is on the correct way around?and on the left side of the bike?

Yeah. It's on the left side of the bike. It is the correct way because the hex is on the inner side.

Should I be playing around with the idea of modding the speedo gear?

[Honda550k]

The way it is right now is basically like the axle is 1 cm too long. So it won't mount on one side

[Ewan 500K1]

those instructions are wrong ... you cannot use an unmodified speeo drive plate.... you DO need to grind it. What you do depends on what sort of front hub you have. If you have the hub with the two flats on it (first picture below), then the speedo drive plate needs modified from the original (on the right in the 2nd & 3rd picture) to be the same shape as part number 44641-300-000 (on the left in 2nd & 3rd picture) ... or if you're very very lucky find an original 44641-300-000 . The tangs on the modified drive plate locate down the sides of the flats on the hub. ( 4th & 5th picture). Note 5th picture shows and additional set disc bolt reatining washers on the speed drive side, normally they are only on the other side.
There are two kinds of unmodified drive plate , one is a single pice , the other is a two pice part with the two parts joined by rubber, modifying the latter is difficult as grinding can melt the rubber.
If you dont have the hub with the two flats on it , you modify the drive plate in the same way, but miss out the tangs. If doing this you need to join the drive plate directly to the hub using screws or dowels or whatever.

[Wobbly]

Alternatively, you just buy the kit with all genuine Honda parts:

http://www.ebay.de/itm/Honda-CB-550-Four-K-F-Screw-Bolt-Nut-washer-Drive-Kit-Double-second-Disc-/360623672076?pt=DE_Motorradteile&hash=item53f6d88b0c

[Honda550k]

those instructions are wrong ... you cannot use an unmodified speeo drive plate.... you DO need to grind it. What you do depends on what sort of front hub you have. If you have the hub with the two flats on it (first picture below), then the speedo drive plate needs modified from the original (on the right in the 2nd & 3rd picture) to be the same shape as part number 44641-300-000 (on the left in 2nd & 3rd picture) ... or if you're very very lucky find an original 44641-300-000 . The tangs on the modified drive plate locate down the sides of the flats on the hub. ( 4th & 5th picture). Note 5th picture shows and additional set disc bolt reatining washers on the speed drive side, normally they are only on the other side.
There are two kinds of unmodified drive plate , one is a single pice , the other is a two pice part with the two parts joined by rubber, modifying the latter is difficult as grinding can melt the rubber.
If you dont have the hub with the two flats on it , you modify the drive plate in the same way, but miss out the tangs. If doing this you need to join the drive plate directly to the hub using screws or dowels or whatever.

Thanks Ewan!  Very helpful. I have the hub with no flat sides on it and the gear with the 2 piece and the rubber in the middle. Sounds pretty straight forward.

[Honda550k]

Alternatively, you just buy the kit with all genuine Honda parts:

http://www.ebay.de/itm/Honda-CB-550-Four-K-F-Screw-Bolt-Nut-washer-Drive-Kit-Double-second-Disc-/360623672076?pt=DE_Motorradteile&hash=item53f6d88b0c

I didn't know Honda actually made a kit for this. If all else fails. I'll be buying one.

[flybox1]

Alternatively, you just buy the kit with all genuine Honda parts:

http://www.ebay.de/itm/Honda-CB-550-Four-K-F-Screw-Bolt-Nut-washer-Drive-Kit-Double-second-Disc-/360623672076?pt=DE_Motorradteile&hash=item53f6d88b0c

I didn't know Honda actually made a kit for this. If all else fails. I'll be buying one.

Honda didn't make kits.  The listing is for a nicely produced kit.
If you don't want to modify the speedo drive plate, you can always buy a disc with the carrier modified to accept it.
see member Godferry's website.

[Ewan 500K1]

Thanks Ewan!  Very helpful. I have the hub with no flat sides on it and the gear with the 2 piece and the rubber in the middle. Sounds pretty straight forward.

... not sure the grinding trick works with the two piece & rubber drive plate ... I think its just the danger of the rubber melting, but not 100% sure.   In addition to what I've descibed there are other methods, like milling the disc to take the tangs on the standard drive plate.. searching for Dual Discs will give you some ideas.   That kit is maybe the easiest option ?

[Wobbly]

Alternatively, you just buy the kit with all genuine Honda parts:

http://www.ebay.de/itm/Honda-CB-550-Four-K-F-Screw-Bolt-Nut-washer-Drive-Kit-Double-second-Disc-/360623672076?pt=DE_Motorradteile&hash=item53f6d88b0c

I didn't know Honda actually made a kit for this. If all else fails. I'll be buying one.

Honda didn't make kits.  The listing is for a nicely produced kit.
If you don't want to modify the speedo drive plate, you can always buy a disc with the carrier modified to accept it.
see member Godferry's website.

Honda didn't make a kit as such, but this kit is made of genuine Honda parts.

[Honda550k]

Flybox: thanks. I've contacted Godffrey about his speedo drive gear.

Ewan: I'll report back if I'm successful in doing so. If not I will need to buy a modded one from Godffrey.
Edit*** I did manage to grind down the speedo gear. No rubbers melted or anything.

Wobbly: good to know that we have many options when doing the conversion. I thought I researched this dual disk subject thoroughly. I guess not!

[Honda550k]

Just to clarify. When I do drill on the bearing to bolt on the speedo gear to it. Am I going to be hitting any balls if I go to deep?

[flybox1]

You either modify the speedo drive plate, or you modify the rotor carrier to accept the stock speedo drive plates tabs.
there should be no drilling of any bearings..

[Honda550k]

You either modify the speedo drive plate, or you modify the rotor carrier to accept the stock speedo drive plates tabs.
there should be no drilling of any bearings..

I see. So where does this speedo plate bolt on to?
http://m.ebay.de/itm?itemId=360623672076
Mine pretty much looks like that now.

[flybox1]

does your hub have two flat sides to it, or is it round?
if your hub is all round, yes, you drill and tap holes in the hub (not the bearings)to accept the flatheads and mount the drive plate...

if it has the two flat sides, your speedo drive plate needs to have flat tabs on two sides to fit the flats on the hub.  if your drive plate is still round, tabs can be bent to make it fit.

see this thread and pictures of the two different setups based on hub type...
http://forums.sohc4.net/index.php?topic=14801.msg148858#msg148858

[Ewan 500K1]

have a gander at that german ebay kit link, that'll show you where the holes are in the speedo drive plate. You'll want to drill that first and use it as a template to show you whre to drill the hub

[flybox1]

you'll only need to drill mount holes if your hub is round, or if the OD of your drive plate is now too small to make and bend tabs to fit the flat sided hub

[Honda550k]

does your hub have two flat sides to it, or is it round?
if your hub is all round, you drill and tap holes in the hub (not the bearings)to accept the flatheads...

if it has the two flat sides, your speedo drive plate needs to have flat tabs on two sides to fit the flats on the hub

see this thread...
http://forums.sohc4.net/index.php?topic=14801.msg148858#msg148858

Crap! I should've seen that thread before grinding my plate. Lol. That mod is more convenient than having to drill through the hub and plate. Oh well. I'm already this far to fully commit.

[flybox1]

yes, if you have the hub with flat sides, the "tab" modification to fit the hub is about a 10 minute job 

Measure twice.  Drill once. 

[Honda550k]

OK. I managed to do the conversion successfully. I will write up a "how to" tomorrow and the ins and outs of the conversion. I learned a lot of stuff along the way. Thanks for the help guys. I will say this though. I never want to bleed brakes ever again.

[flybox1]

OK. I managed to do the conversion successfully. I will write up a "how to" tomorrow and the ins and outs of the conversion. I learned a lot of stuff along the way. Thanks for the help guys. I will say this though. I never want to bleed brakes ever again.

Speed bleeders, man!  I'll never bleed brakes without them! 

[Honda550k]

HOW TO DO A DUAL DISK CONVERSION ON CB550

Things you need:
-rotor
-Caliper arm
-Caliper
-brake line
-brake pads
-double banjo bolt (to take 2 brake lines)
-a master cylinder big enough to push 2 pistons (any bike with dual disks master cylinder should work)
-6 8×110 bolts

Front wheel mods:

First things first. Remove the front wheel. You then have to remove the axle. The axle is basically a really long fancy bolt with the nut in the left end of the axle.

Install the second disk and run the bolt through the speedo drive first.

Remove the following:
- Chrome retainer speedo plate
- speedo gear plate

*when the second disk is fitted, the axle does have enough space for the chrome retainer.

Now this will probably be the hardest part of the conversion. We now need to mod the speedo plate. The shape of your right hub determines how you mod your plate.

If you have a hub with flat sides then you can see the first and second pic on how to mod your speedo plate.

http://Http://www.imgur.com/QsyO

http://Http://www.imgur.comkXeqjki

Or

If you have a rounded hub you have three options:
Option 1.
You can either grind the sides of the hub to make 2 flat sides. Then cut sleep plate the same as picture 2.
Option 2.
If you don't feel like grinding the hub you can cut the speedo plate the same as picture 2 but without the 2 tangs on each sides. With this option you would have to drill through the speedo plate and a hole on the hub. Tap the hole on the hub and bolt the speedo plate against the hub. Use a taper bolt so it's nice and flat.
Option 3
If you want it easier. You can find member Godffrey's website as he has a couple of bolt on options for this.

Now put everything back as you would. Do not over tighten the axle as I accidentally cracked my speedo drive. Remove the front Fender and left calipers.

Mount the front wheel back on the forks. Then install the second Caliper arm. Stand directly in front of the front wheel and you can see that the right arm is way more angled and the left arm. You have to grind the Caliper arm holder that takes the 14mm bolt to even out the angle. When you achieve the right angle install both calipers.

Install the brake lines to the master cylinder and the calipers. Install the new pads. For you to install the front fender you would have to bend the right tabs.

I lied. This is probably the hardest part of the conversion. Bleed the brakes.

*if you are experiencing a stuck wheel. Check that the nylon ring behind the pad is installed correctly. Or you may have to rebuild the Caliper.

*If I am missing anything. Please let me know as I will add it on. Ewan I used your pictures.  Thank you. Thank you everyone. I learned a lot along the way.

[Honda550k]

OK. I managed to do the conversion successfully. I will write up a "how to" tomorrow and the ins and outs of the conversion. I learned a lot of stuff along the way. Thanks for the help guys. I will say this though. I never want to bleed brakes ever again.

Speed bleeders, man!  I'll never bleed brakes without them! 

Yeah I thought I didn't need one. I had a fore arm workout good for a week.

[Ewan 500K1]

does your hub have two flat sides to it, or is it round?
if your hub is all round, you drill and tap holes in the hub (not the bearings)to accept the flatheads...

if it has the two flat sides, your speedo drive plate needs to have flat tabs on two sides to fit the flats on the hub

see this thread...
http://forums.sohc4.net/index.php?topic=14801.msg148858#msg148858

Crap! I should've seen that thread before grinding my plate. Lol. That mod is more convenient than having to drill through the hub and plate. Oh well. I'm already this far to fully commit.

No worries about using the pics, but thought u said you had the hub without the flats ?    .. which option did you go with in the end ?