Drop in fork cartridge kit for the 750

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Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Drop in fork cartridge kit for the 750

Post by Freddy »

Just noticed japan.webike advertising drop in no modification necessary Matris cartridge kits for the front forks of a Zephyr 750. Convert them from antiquated damper rod (hopeless) to modern cartridge forks. Certainly be cheaper and a LOT easier than trying to retrofit upside down forks.

https://japan.webike.net/products/23642851.html

I've shot of an email to the local Matris agent in Australia to get them to confirm the kit will in fact fit (I no real reason to doubt it does as I've always found japan.webbike to be accurate in what they say fits). Anyhow just thought I'd pass along this discovery.

If they do fit, I'll be seriously think about sticking a set in.
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Drop in fork cartridge kit for the 750

Post by Freddy »

I've received confirmation from Matris in Italy that their cartridge fork Kit F15K131K is specifically intended for a Kawasaki Zephyr 750.

I got them to send me the installation instructions (titled Kawasaki Zephyr 750), and basically all it involves is pulling the guts out of the existing forks, unscrewing the existing damper rod (bolt is in the bottom of the fork leg), fitting the existing top out spring and oil lock to the new assembly and bolt it in. Fully adjustable cartridge compression damping in one leg, and rebound damping in the other.

The big advantage of this kit is that no modification to the forks has to be made. Most other products involve machining the end of the inner tube so the valve at the bottom end can be removed. So its non reversible. With the Matris kit it simply goes through the valve just like the original damper rod.
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Drop in fork cartridge kit for the 750

Post by Freddy »

Anyhow, I've decided to proceed with giving this cartridge kit a go.

Feedback is the product is very well made, but the compression damping valving is way too firm. The suspension shop I plan to buy them from are confident they can be revalved to correct this problem (for an extra $50 on top of the purchase price).

I think there will be a problem with the forks caps (containing preload-adjusters with damping adjusters). The problem is insufficient clearance between the fork caps and stock handlebars. Even with the stock fork caps there is only 9 mm of clearance to the bars. I've asked the suspension shop to ask Matris in Italy how they see this issue for a product specifically marketed as for the Zephyr 750. I'm already planning a workaround as I doubt they really have a solution. My work around is fit a pair of 30mm bar risers and then fit flat 'drag' or very low rise bars to restore the original grip position.

Another thing that needs to be corrected in advance, which I recently discovered is at 160,000 kilometers both lower fork legs are completely rooted. There is massive wear in the lower fork legs where the lower fork bushing run. Even with new bushings the inner tube flops around on its lower end when inserted to this position. I've already replaced the left hand side, and the right side is currently in transit. These things are not cheap.

I'll also complete the exercise of converting the wheels to tubeless prior to fitting the cartridge kit.
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Drop in fork cartridge kit for the 750

Post by Freddy »

An update on this project .....

Decided not to go with the Matris F15K kit (seems to be too many uncertainties regarding the compression damping valving as supplied). Instead going to fit a Traxxion Dynamics AK-20 cartridge kit.

This requires modification of the inner fork tubes. The damper rod sealing valve in the bottom of the inner tubes needs to be completely removed. This requires the retaining 'lip' on the bottom of the tubes to be machined off, and then the valve punched out. This is so the cartridge which bolts in the same place as the damper rod will fit. As this is a permanent modification I decided rather than destroy the OEM fork tubes I'd rather do that to a pair of aftermarket inner tubes. So sourced a reasonably priced aftermarket set from Japan webike. They seem high quality and a perfect match in every dimension.

As there is limited clearance between the stock fork caps and bars, I've sourced a near identical to OEM set of bars with about 25mm less rise in them. Also bought a set of 25mm bar risers. This will then place the hand grips in the same position as stock (I like the current position) but give 25mm more clearance between the fork caps and bars.

As Traxxion Dynamics need a complete fork as a sample to make up the kit. Rather than have my bike off the road for possibly months (sending my forks to the USA, then waiting for a completed kit to return and fit) I've purchased a cheap complete fork on EBay and its in the process of being delivered direct to Traxxion Dynamics.

Anyhow, its all happening ......
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Drop in fork cartridge kit for the 750

Post by Freddy »

Latest update on this project .....

Purchased a second hand fork in Germany and got it posted to Traxxion Dynamics in the USA. This was so that would have a sample to base the cartridge kit on.

After 2 months from receiving the fork, they still hadn't started work on the task, so I basically told them to stick it, and demanded they return the fork to me in Australia (at their expense). To their credit they have done so and I've now received it.

So, plan C ... its back to using a local suspension house to build the cartridge kits, using a Matris F20K kit. This requires the damper valve in the bottom of the inner fork tubes to be removed so the cartridge goes through (where the damper rod normally goes. This has already been done using a set of non genuine inner tubes I purchased online Japanese Webike. Didn't want to irreversibly destroy my current fork tubes in case I do need to 'roll back'.

So that' where it's up to. Just got to take the second hand sample fork tube and the machined inner tubes to the suspension shop this coming week, and hopefully they should be ready to fit in 3 or 4 weeks time.
Gdonald
Posts: 2
Joined: 03 Oct 2018, 21:50

Re: Drop in fork cartridge kit for the 750

Post by Gdonald »

I would be interested in an update to the fitting of the Matris cartridges and the problem of the preload adjusters fouling the bars.
I would like to fit these but find it hard to believe that Matris would make them for the Zephyr without checking if they actually fit.
Webike in Japan tried to tell me my bike must have been fitted with modified handle bars. Would like to get a copy of the fitting instructions if possible. My email is gdonald@internode.on.net

Greg Donald
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