Aftermarket upgrades that are actual upgrades.

Are spray carburetor cleaner any different than brake cleaner?

Funny, DoctoRot I was going to say brake cleaner isn't good for rotors as it evaporates too quickly leaving residue behind.
I think Michael Mercury Morse also mentioned using denatured alcohol as well as acetone to clean rotors.

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Funny, DoctoRot I was going to say brake cleaner isn't good for rotors as it evaporates too quickly leaving residue behind.
I think Michael Mercury Morse also mentioned using denatured alcohol as well as acetone to clean rotors.

Thank you for clarifying it for all the members of this forum. 

Replacing stock fork springs intended to use an air supplement (meaning they are super soft) with some aftermarket springs that don't need air assist like those from Sonic.  Progressive suspension fork springs are also popular but Sonic's are better in my opinion since they are straight rate like most all modern springs being used for forks.  Sonic has a good discussion on the topic if you care to study.

Teflon/stainless brake lines are also a huge upgrade.  I prefer making my own lines from made in USA Earl's parts but there are other options too.  With the Earl's parts you can configure the lines just like you want, shorter for different handlebars for example, plus they are cheaper than most aftermarket lines with crimp on hose ends.  And the Earls bolt together lines have a higher pull off force compared to crimp on hose ends too so that's an additional bonus.

-Racetech springs and emulators
-modern tires
-hagon/progessive shocks
-braided steel brake lines
-tarozzi fork brace

those things will go a LONG way in improving an old bike, after a full service of course 

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Replacing Sonic's are better in my opinion since they are straight rate like most all modern springs being used for forks.  Sonic has a good discussion on the topic if you care to study.

 

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I was just looking at both Sonic and race tech. I noticed that, for the kz1000 forks, race tech recommends 0.9 to 1kg/mm for a 200 lb. rider, and Sonic lists three rates from  0.9 to 1.1kg/mm.

Interestingly, the FSM says the kz1000 A1, A2, and D1 came with 1.6kg/mm springs.

These forks are not air pressure forks, just simple damper rod. I'm really surprised that the factory springs are 70% stiffer than the aftermarket recommendation. I'd like to understand the thinking behind that.
Do these folks also assume the damping rods will be replaced with something better?  Does that matter? 
Have we just come to understand that softer is actually better?

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Replacing Sonic's are better in my opinion since they are straight rate like most all modern springs being used for forks.  Sonic has a good discussion on the topic if you care to study.


 

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I was just looking at both Sonic and race tech. I noticed that, for the kz1000 forks, race tech recommends 0.9 to 1kg/mm for a 200 lb. rider, and Sonic lists three rates from  0.9 to 1.1kg/mm.

Interestingly, the FSM says the kz1000 A1, A2, and D1 came with 1.6kg/mm springs.

These forks are not air pressure forks, just simple damper rod. I'm really surprised that the factory springs are 70% stiffer than the aftermarket recommendation. I'd like to understand the thinking behind that.
Do these folks also assume the damping rods will be replaced with something better?  Does that matter? 
Have we just come to understand that softer is actually better?

Something doesn't seem right with those specs.  I seriously doubt the KZ springs were actually that stiff, and if they were, they were miss rated.

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Something doesn't seem right with those specs.  I seriously doubt the KZ springs were actually that stiff, and if they were, they were miss rated.

The numbers are consistent in the FSM from 73 to 78.  The Z1 white manual shows 1.6kg/mm, as does the blue 73-76 and the brown 77-78.  Although the free length changes every few years.  It isn't until 79 KZ1000A3 that the rate changes to 1.2 kg/mm, and the 80 A4 & D2 use the same, again with different free length.

The 81-83 KZ1000/1100 shows the switch to air pressure forks, and in '81 8the springs drop to 0.5 kg/mm for EU, AUS models, and 0.4 kg/mm for US, CAN.  This matches your statement that the air forks used very soft springs.  After that it looks like they start playing with progressing springs.

And of course the modern manuals, like for the ZRX, don't share that info.  I guess it's a trade secret.

Best front brake master cylinder rebuild kits?

Best front brake master cylinder rebuild kits?

If you mean Zephyr, the best choice is a complete set of EX650 (Ninja 650) front brakes: calipers and master cylinder. The lower mileage and and the fresher year the better. These brakes are the best straight bolt-on option for Kawasaki Zephyr 550 and 750. Looks like this:

Ebay item 124910436901

I mean in terms of reliable brand names for any bike, as is the intended theme of this thread. The question being is OEM best, or is there an aftermarket brand that makes an equal or better product?

Though you are correct that I am interested for my Zephyr 550. Just curious, but how or why is the Ninja 650 brake better than the stock Zephyr brake? I mean all things being equal, say if you had both fully refreshed and functioning like new, what is it about the Ninja 650 brake that’s superior? 

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Best front brake master cylinder rebuild kits?

Personally, I prefer stock brake system parts.  Lots of guys here swear by Brakecrafters though.  Their kits use stock pistons, or at least some of them do.