Kawasaki Twinpot Brake Modification - who wants parts?

[willycrash]

uhm...any of these brackets left?

uhm...any of these brackets left?

uhm...any of these brackets left? and if so, are they available to complete strangers such as myself?

 

[salty_monk]

Yes & yes if you don't rip me off like the other almost complete stranger that had some....

 

[salty_monk]

Well here is phase 3 fitted....

Saves about 1.5lb over stock slotted rotors, 2.5lb over stock non slotted & about 6lb over the mod using GS550 Rotors.

unfortunately fitting these Honda CBR rotors really tightens up the tolerances. The spacer I have fitted I dropped in with a set of pads nearly on the wear limit as I wanted to check tolerances & I knew this would show me the extreme (about 2.5-3mm left a side of friction material) & the nearside pad is at risk of being able to drop out of the caliper...! :no:

The spacer I am using puts the inside of rotor the same distance from the wheel as the 550 rotor but being 3mm thinner the inside (of the caliper) pad has to move over an extra 3mm to compensate. This is just too much.

Fortunately the answer is simple... run an extra 2mm of spacer (which then brings the rotor rivets around 1.5mm away from the bolt (you have to be really careful what bolts, washers etc you use here!)

The other answer is to run pads down to a wear limit of around 5mm a side but I think this means you would be using only about 1/3rd of the pad from new!

I will be keeping the CBR rotors, need to get a friend to knock a few thou off a 2nd set I have so I can double them up & then I'll be running new pads & setting my wear limit to approx 3mm.

Here's some pics....

Dan

P.s. I still have brackets & bolts for sale plus I now have one full set which may go on Ebay.... Rotors, calipers & brackets / bolts. Everything except a caliper rebuild kit & pads.

P.p.s I don't have any sets of these spacers necessary to do the CBR rotor swap available yet (I *may* have one set) but I will probably get a few sets made up later this year.

 

[Suzuki_Don]

Well here it is. The variation on Dan's (AKA Salty_Monk) CBR front dual disc conversion. It has been done with:

The bike used is a '77 GS550B with wire wheels.
The narrow head stock used for the single disc Suzukis.
GS650G front forks with Progressive's springs and an overhaul (seals, etc.)
Salty_Monk's mass produced custom brackets (still available from him).
'89 Kawasaki Ninja ZX 600 twin piston calipers.
The disc/rotors are off an early 90s model CBR900RR Honda.
Stainless steel brake lines up to master cylinder (no junction below headlight).
Salty's brackets have been installed inside the fork mounting lugs instead of outside as is standard practise.

When Jeff (8TRACKMIND) did his 550 twin disc conversion a few years ago he had to cut the spacer down on the right hand side with a drill and cutting wheel. I was fotunate enough to have the front axle from a GS650 which had a shorter axle spacer by about 3mm and this was perfect for the job and there was no grinding or cutting required.

In fact this turned out to be a straight forward swap. Salty mentioned on his conversion that there may be a risk of the pads dropping out if not monitored as far as wear goes. This conversion was the opposite. I could only just get the new pads in place.

I think I have covered everything.

My only problem is my motor is still in pieces on the work bench so I cant try these brakes out for a while.

 

[salty_monk]

Well I "got er dun" & the CBR disks are fitted with new pads, all looks great. Works well too. No huge braking performance difference over the GS550 disks that I can feel (possibly a little) but I imagine they would come into their own in the wet.
Losing 7lb in Unsuspended weight shouldn't hurt things either in the handling stakes.

I finished up with the double spacer fitted but here's the strange thing... the distance from disk surface to inside surface of the caliper mount bracket (both of which are fixed as Don described earlier) are different. There's approx 2mm between them. This is not a big deal as I used a shorter bolt on one side & ended up with clearance of around 2.5mm - 3mm on one side & about 3.5mm - 4mm on the other.
In the end I will likely fit a 5mm disk spacer one side & a 3mm the other to even things out.

Now it gets even more interesting... when I measure my skunk (twinpots with GS550 disks) they are different in the same way but only by 1mm! Strange! This also seems to tally up with what Don saw on his setup, they are slightly different.

My guess is this is all due to Suzuki's tolerances & is also perhaps partially intended.

Some more good news... I should have spacers for those that want to do the CBR disk / Twinpot upgrade the middle of next month!

One last thought - if anyone has time to put a vernier caliper between their caliper mounting bracket & nearest disk surface (Jeff I'm particularly interested in yours) & report back I'd be interested to know the results, see if the differences are consistent or different or ??

More pics to follow later.

Cheers,

Dan

 

[first timer]

see if you can get some ebc HH padss for those calipers you should really notice a bite then.

 

[salty_monk]

Maybe next time I'll go a different pad compound but even with what I have & not bedded in they are a huge improvement over stock!

 

[salty_monk]

 

[steve murdoch]

Dan, are the CBR rotors from an F3?
What thickness of the rotors would be optimum or do you think getting yours turned down was a one-off?
I am hoping to put these on my spoked '78 GS1000.

 

[salty_monk]

They are F3 rotors. I didn't get any rotors turned down, I just used different thickness of spacer behind the rotor. The rotor is stock 4.5mm thick at braking surface. That matches the Kawa rotor that came with these calipers originally.

I am going to have some rotor spacers available next month for anyone who wants to do this mod incl CBR rotors.

Dan

 

[Old Colt]

Hi Dan,
One item I do not understand with your setup here.
Why do you need spacers behind the rotors?
Why not use your caliper adapters as spacers and move the calipers inwards as needed?

 

[salty_monk]

Mainly because there is not enough space between the wheel spokes & the fork legs to get a decent thickness of spacer between the 2....

I wouldn't want the caliper bottom bolt only attached to 1/8" material, would you?

Dan

 

[Old Colt]

I wouldn't want the caliper bottom bolt only attached to 1/8" material, would you?

If it is the proper material, sure. Especially since that is all the caliper bracket is. If working with aluminum use 7075 alloy.

 

[salty_monk]

The caliper bracket on mine is at least 4 or 5mm & it's not Aluminium it's steel & appears to be a hardened variety... The part the bolts go through including thread is approx 8mm.

What would concern me most about using that setup is that if the caliper got knocked it would have enough leverage to bend the bracket, it would also be very tight between caliper & the wheel.

Each to their own I guess, this way is working out fine & is almost identical in position, rotor thickness etc to how it is as stock on the Kawasaki.

Dan

 

[Old Colt]

I thought your disc spacer was thicker than 1/8.

I expect the Bandit calipers I used may be a bit smaller than the Kawi units. Mine has plenty of room to the spokes and the Suzuki bracket is is only about 4mm thick but is extruded where the fasteners are.

 

[salty_monk]

I would think so given that they newer. I would prefer them on the inside if it was feasible because I think it would probably give a cleaner look.

Don in Australia has managed to work something with my brackets on the inside but he doesn't have such a "near stock" positioning that I have although it's not too far off.

Dan

 

[Suzuki_Don]

I would think so given that they newer. I would prefer them on the inside if it was feasible because I think it would probably give a cleaner look.

Don in Australia has managed to work something with my brackets on the inside but he doesn't have such a "near stock" positioning that I have although it's not too far off.

Dan

Dan I am going with another idea now. I am not going to use your brackets. I have developed a new bracket that is almost not visible to the eye that fits on the inside of the fork lugs. I have made them from steel plate and am using a different threaded hole on the Kawa caliper bracket. There are four holes on the Kawa bracket and there are a few options available to the would be modifier. I am now using the two threaded holes that the standard Kawa uses. When I get a chance I will put up some pics of the new brackets and the overall setup on the 550.

Picture of Kawa setup below.

 

[salty_monk]

Be interested in seeing the pics Don

 

[Suzuki_Don]

Be interested in seeing the pics Don

Dan see pics below of brackets. they weigh 1 oz more than the aluminium brackets.

 

[Suzuki_Don]

These are the calipers fitted with the steel plates. The plates will be painted black to match the calipers and will not be very noticable when finished. I now have 8mm clearance on both sides of the wheel between the disc and the caliper bracket as discussed earlier, also in UJM site.