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Twinpot Brake upgrade on 78 Skunk

Sorry will try to answer a bunch of points....

Blackbird 310mm rotor - It works with the brackets I have but the caliper overhangs the edge by about 5mm so you have to chamfer the back of the pad (friction material) to stop it wearing an edge. Reportedly it works very well though. A few have done it.

320mm Rotor - Should be the perfect size but I haven't been able (despite multiple ebay purchases on possibles) to find something with enough offset in that size. The problem with that rotor is that spacing it out would get in the way of the speedo drive so I guess the answer is that you could make it work if you moved to an electronic type aftermarket speedo.

The twinpiston thing to google is "swept volume" if you want to understand why longer pads & more pistons give more power. Rotor size gives more leverage for a given caliper "power".

For pulsing - check the back of you rotor, any spacer etc are flat (wet n dry on a piece of glass). Other than that it could be related to the rotor, either they are warped or not moving right. The floating function doesn't open up until they have some heat in them in my experience - I've only ever had one set you could spin by hand & they rattled like crazy (a tinkling sound at low speed).
 
Sorry will try to answer a bunch of points....

Blackbird 310mm rotor - It works with the brackets I have but the caliper overhangs the edge by about 5mm so you have to chamfer the back of the pad (friction material) to stop it wearing an edge. Reportedly it works very well though. A few have done it.

320mm Rotor - Should be the perfect size but I haven't been able (despite multiple ebay purchases on possibles) to find something with enough offset in that size. The problem with that rotor is that spacing it out would get in the way of the speedo drive so I guess the answer is that you could make it work if you moved to an electronic type aftermarket speedo.

The twinpiston thing to google is "swept volume" if you want to understand why longer pads & more pistons give more power. Rotor size gives more leverage for a given caliper "power".

For pulsing - check the back of you rotor, any spacer etc are flat (wet n dry on a piece of glass). Other than that it could be related to the rotor, either they are warped or not moving right. The floating function doesn't open up until they have some heat in them in my experience - I've only ever had one set you could spin by hand & they rattled like crazy (a tinkling sound at low speed).
A while ago I bought an EBC MD1124LS, which is 320mm. Its for a T500 cafe build that will have a GT500 triple tree, 81 GS550T forks & your twin-piston brake upgrade kit.
Am waiting to get the frame back from the powder coater. I have the rotor but don?t have the triple tree, so I can?t bolt things together to check the offset.


Are you now of the opinion that this combo won?t work?


More info is in this old topic: https://www.thegsresources.com/_for...e-on-GS550E-GS750C-GS1000C&highlight=md1124ls
 
No that's about the best one I've seen but I can't find the offset numbers for it either. Also very hard to get hold of so I've not tried one.

If you put the rotor face down on a flat plate what does it measure to the back side through the centre hole?
 
Looks like an excellent match.
The MD1124LS compared to a GS rear rotor that we used to have on the front of a GT250. That GT250 now has an EBC VMD rotor & your twin-piston adapter kit.
cafe-T500-0836 by jabcb, on Flickr


Don?t know what variations EBC has. The center section of my rotor is gold & nicely matches the gold Suzuki winged ?S? badge from about 1970.
cafe-T500-0808 by jabcb, on Flickr
 
Salty, sent you a PM.

I'm going from a single disc GS750B to the 2 piston dual disc setup. Should have some dual disc forks soon so I'll be starting like a GS750EC.

I've read through this whole thread and I have a few questions. I replaced the hoses with stainless steel when I bought the bike 3 years ago. Currently have one line from the master cylinder to the splitter under the headlight and a second line from splitter to caliper. I'm planning to add a double banjo bolt with a third line from splitter to second caliper. Any issues?

Where do the mounting bolts go? The first existing bolts goes through the upper mount of the fork and second through the adapter bracket, spacer, and caliper mounting plate? And the 40-45mm bolt with nut goes on the lower fork mount? Use blue loctite on all three?

I read that non ABS VTR750 rotors will work. Can anyone confirm? They look just like the 95-96 F3 rotors.
 
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PM sent back. No problem with that line arrangement, that's what they do OEM. Correct on the Bolts. Yes I believe those rotors work. :)
 
Thanks! Got the calipers on the way and working on the rotors and master cylinder. I'll PM you for payment details by the end of the week.
 
Ok, I am taking the kids camping & getting in some riding whilst away so forgive me if I don't respond till next week. :)
 
So this thread is very large and I haven't read the whole thing. Is there a parts list for this install for a 78 GS1000 factory twin disc bike? Is there a kit anyone knows of? Love my Skunk, stops like ****.
 
Thanks - I posted that post linky into the first post of the thread. :) PM back to you today.
 
On the page that Hannibal posted a link to you it states, "Suzuki also used this caliper on the VX800, GS500 and the GSX1100G". Can someone tell me if there is a specific yr model I should be looking for?
Thanks,
Willie
 
Earlier GS500's, 1989 through roughly 2001/2003 use this exact Tokico caliper. I believe the later AJP versions will also work with this mod as they use the exact same fork mount positions as far as I can tell.

EDIT - EXCEPT that all GS500 calipers will only work as the right side caliper of a dual disc 77-88 Suzuki GS, because as far as I know, all the 77-88 GS's run a left caliper only, on all single disc setups, and the GS500's are all right side only, single discs.

Any year GS500 master cylinder will work for this mod on a single disc bike, but on the calipers, i dont know what models you would look at ti find a matching left side AJP caliper to match the right side later GS500 AJP style.
 
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Thanks for responding Chuck. Does anyone know if one particular bike model caliper would be better than another?
 
They are all the same calipers if they use the universal Left/Right bracket with the holes drilled in it, but the calipers themselves are specific left vs right. And we are talking about the calipers that use one large leading and one small trailing piston (some very similar tokico calipers used 2 pistons of equal diameter, I believe they have a slightly different bracket that is not universal left and right. This may also work with these bracket kits, but I am not certain).

Just look up front brake calipers from those three Suzuki models or any of the Kawasaki models listed, and look at the photos of the calipers for sale. The calipers you want have an unmistakable appearance.

Also you can use the alpha sports or Partzilla websites which have cross reference information on the individual part pages. Find a caliper in the parts fiche schematics/diagrams that looks like the one that we are using here, then click on each caliper, left and right, and it will show you every year and model that exact caliper in that exact color came on. The Kawasaki's get complicated because they had different paint color variations that make the cross-referencing not as straightforward (identical brake calipers but in a different color will have a different part number). In that case, you can use the piston seal part numbers for the pistons themselves actually, and get a better idea of exactly what years to look for.
 
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The last of the breed for the calipers than work are the 2001-2006 Kawasaki Concourse & the up to 2006 Kawasaki Ninja 250 (except it has one side only).

I usually go for the Concourse ones when I can get them. In general they seem to be in better condition, maybe because of the age. :)

Those calipers are silver. Most of the calipers out there are black.
 
Greeting's. Salty's original inspiration 10 years ago to upgrade the caliper's and rotors for the GS series motorcycles used CBR rotors and Kaw Concour calipers were the best cost effective options.
The aftermarket now has cost effective alternatives for new rotors. Are there brand new (Asashi?) rotor, rotor carrier, and buttons that can be recommended that don't require drilling modifications? Part numbers would be helpful. Ebay is such a crap shoot.
Thank you for your time
 
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