Twinpot Brake upgrade on 78 Skunk

[gssteve]

hi salty
I have GS 750 1979 Model and wiuld like to upgrade the calipers.
Do you have the brackerts for sale?
steve

[salty_monk]

Yes I still have some kits on my shelf. It's about $135 (USD) all-in to Australia depending on what shipping you want. I wish a few more of you guys would club together, the flat rate boxes would easily take half a dozen sets for no more shipping cost

[Knowbetter]

Please advise by PM if you have a kit still available for a 79 Gs1000L. Thank you, Alan

[salty_monk]

The kit doesn't work on a typical L fork (leading axle). You'd have to either change to axle under type fork legs or use the brackets as a template to cut one specifically for the L. All the spacers etc would work....
It's been done before using one of these kits as a base but not by me. I've never had an L to play with (and there's not a lot of demand).

[Jofka]

Good afternoon,

i have had my 1983 gsx 1100es for several years and have recently become aware i would perhaps like to stop a little sooner, old age and reaction times perhaps, bit of a long shot but you wouldnt happen to have an adaption kit and list of parts for a 1983 GSX 1100 es? im in the uk.

regards Neill

[salty_monk]

Hi Neil - I just got back from there, could have bought you a set of brackets over... I do still have some on my shelf. I'll PM you. Dan

[garyS-NJ]

Finally bolting up the salty monk twin pot upgrade on my 1979 gs1000e and I see the speedo drive dust seal (#10 in parts Fischer metal shield with 6 holes for rotor bolts) extends about 4mm past the wheel hub. I don't see why I should trim the dust seal in fact I think it should be longer to further envelope thd speedo drive. Now I'm wondering if I trimmed it before powder coating. I remember in this post with directions there was something about trimming the dust seal and just read that was for some later bikes. So I laid the wheel up the speedo drive and see that the drive fits into the dust seal and there's a ledge on the drive so the seal extends around the drive and that ledge on the drive is sbout that same 4mm.
this is where I'm scratching my head because the tabs on the speedo drive only extend about 0.030" into the hub notches barely giving much drive surface. But the speedo drive itself laid up against the hub hits home to the wheel bearing inner so even with the old stock rotor, or untrimmed dust seal (if I did trim it), I would not have deeper contact between the speedo drive tabs and the hub notches. This is looking like I should trim the speedo drive itself so the drive tabs extend deeper into the wheel but that don't make sense because I'm sure the drive inner is flush with the wheel bearing inner acting like a spacer in which case the only way I'd have more tab contact area would be to use a different speedo drive (or tab washer which is removable with a snap ring.
now I know I'm sounding like an idiot because even with just 0.030" tab to hub notch contact, the wheel does drive the speedo. All that said, the dust shield definately isn't holding the speedo drive out so I'm thinking I should bolt it up because it will be how it was with the old rotors

[salty_monk]

Your assembly is wrong. The drive dust cover goes on the OUTSIDE of the rotor. You have it on the inside against the wheel.

also some general comments to your PM follows (before I saw picture)

The kit won’t affect the way the Speedo drive interacts with the wheel. Whatever you had before should be exactly the same after.
what does happen is that when you tighten the axle the Speedo drive itself binds on the dust cover. It’s pretty easy to see and feel if you’re looking for it (the wheel won’t spin easily by hand although you may be able to force it around).
not all dust covers need cutting back, usually the pre 1980 ones are ok and the post 1980 ones need trimming but it’s not a hard and fast rule as lots of parts have been swapped around on these old bikes over the last 40 odd years.

Cheers,

Dan

[hookemdevils22]

Add my 82 650G to the list. Just finished this evening: CBR600F4 rotors, EX650 calipers and master cylinder. I wasn't able to do much testing because the left side CB rotor was warped.

I weighed all parts and shaved 946g (2.09 lb) off the front, all of which is unsprung and most of which is in the rotors (664g/1.46lb less rotating mass including salty spacers). That also includes the 641g (including the additional pair of M10-1.25x40mm bolts + nuts needed) for salty's spacers and bracket.

I also picked up calipers from a Concours ZG1000 (140g heavier each as compared to EX650, 160g each lighter than stock) and radial masters from an 05+ R6 (16mm bore) and Kawasaki Concours 14 (11/16" bore) for further testing. I'll have a separate write-up with hydraulic ratios, a calculator, full weights, and more.

[salty_monk]

Pull that rotor off and make sure the back of it is flat. I usually kiss the holes with a countersink and then run it on some paper on a flat surface. You need the mounting surface to be totally flat.
In my experience that’s been more common cause of pulsing than a warped rotor.

thanks for doing all the weighing and math!