TOPIC:

I got the ZRX and the Hyosung back from Race Tech. Both bikes had the front and rear suspensions re-done. All I have to say is “HOLY SHIT!” To call it a night and day difference would be an extreme under-statement.

First the ZRX: The front forks were WAAAAAAY under-sprung and under-damped. They installed stiffer springs up front and the new G2R gold valve kit. When I would let off the gas the bike would always dive forward. That was made worse when I was not 100% perfect with the throttle in a turn. Even the slightest change in throttle would upset the suspension. Not anymore! The front end is ROCK Solid. I don’t mean stiff either. It actually feels plusher on the freeway than before. Hard braking doesn’t use up all the suspension travel anymore.

The rear shocks went through an even more intense change. I had After Shocks rebuild the shocks 2 years ago. Unfortunately, they cut a lot of corners and improvements were minimal. I found out that the stock shock is a pretty archaic design. It is basically an old de-carbon style shock that uses check valves and ball for damping. Race Tech completely changed all that.

The shock now has modern valve setup, using a shim type damping system. They also mounted stiffer springs to handle my petite 290lb frame. The difference was noticeable immediately! The bike handles bumps and pothole far better. It tracks straight as an arrow on the lovely grooved freeways. The Rex dives into the corner soooooo much nicer now and is way more stable. This feels like a completely different bike.

I will have more info and some video in a week of so. I am also taking both bikes to Buttonwillow for a track test, with Race Tech on July 5th. The following month we will be doing a 500 mile one day ride through So Cal to test both bike street manners.

BTW…Race Tech is designing a custom shock for the ZRX. It is in the works now and should be SWEEEEEEEEEET!

Now, to the Hyosung GT650. This is the bike that I purchased for $2K last year. It is a 05 and had 154 miles on it. This had the most issues, by far of both bikes. The front end is a fairly modern upside down cartridge fork. The cartridges are circa mid 90s design and are rebuild able. That is the good news. The bad news…no damping! Not a single shim is used in the forks to offer any damping. It is a free flow proposition. I guess that is why the felt like a 72 Lincoln…Bouncy, Bouncy! The springs were setup for a 120lb rider. I guess everyone is very weight conscious in South Korea.

What did they have to do to the Hyo? Basically, the same as the ZRX. They added stiffer springs and the GR2 gold valve kit. The bike went from bottoming out from a 10mph hard stop, to rock friggin solid! It eats bumps and pothole like a starving man at an all you can eat buffet. More on the handling later.

The rear shock was a REAL disaster. The stock shock had way too much damping, was under-sprung and only had adjustments for preload. It is also a non-rebuild-able shock. I think the thing would make a far better paper weight than a suspension component. You simply can’t do anything to this shock to improve it.

So what did Race Tech do? Well, let’s just say I now own the only custom built fully adjustable rear shock for the GT650! Hopefully that will change. This unit is absolutely incredible. It took them 3 weeks to build and setup this shock. It seems Hyosung did not leave much room around the rear shock for bigger springs. Clearance is very tight on this shock. They had to customize an existing spring to get it to work. The reservoir is hidden away in the tail section so as not to stick out or interfere with any of the bikes other components. It is a slick setup!

So how did the bike improve with all this work? Beyond Belief! It had minimally twice the improvement of the ZRX.

We did the most testing on Thursday with the Hyosung and the Speed Triple. The Speed Triple is part of a 3 bike test we are doing. We did about 150 miles of a combination of city streets, freeway and mountain roads. Like the ZRX, I notice the improvements the moment I pulled out of the parking lot. Even though they added hugely stiffer springs front and back, the ride is much smoother. The bike turns with far less effort and is rock stable through the entire turn.

We intentionally sought out the bumpiest mountain roads we could find. These are the same roads we did the tests on the bikes before we re-did the suspensions. I was absolutely amazed at how well the bike tracked through really bumpy corners. I entered these corners expecting a little bounce induced sliding. Instead, the bike rolled trough the corners like the bumps didn’t exists. I found myself looking for bumps and potholes to hit. I intentionally took the bumpiest lines through the corner.

Needless to say, my face still hurts from smiling so damn long. I feel like I just got 2 brand new, really, really great bikes. The handling is beyond belief. I can’t wait to do more testing.

All of the testing is being filmed and used for my TV show I am producing. I am posting sample segments on my You Tube site www.youtube.com/cyclesportstv as they are edited. Subscribe to the site for updates.

Dang, it sounds like Race Tech really knows their stuff!

I'm at the opposite end of the spectrum.
When riding on So Calif freeways, I feel like I'm riding on a desert washroad!
There doesn't seem to be any "off the shelf" rear shocks or front fork springs available for a 140 pound KZ650 rider, and having some custom-made is likely WAY out of my budget.


Give us a heads up when you plan to do your 500 mile one-day ride here in So Calif. I'm sure there'll be at least 6 or more of us that would love to "tag along" on our KZ's for that.

Race tech has begun doing vintage bikes. They may have something available that can be used on your bike. You may want to call, just in case.

BTW I will post up the date of the So Cal Ride once it is finalized.

Didn't Dave Sloan put Race Tech Cartridge Emulators in his KZ650? I know he was researching it and I thought he had it done.

I may be mistaken though, that was a couple of years ago.

I've toyed with the idea of emulators for my Z1R, but have yet to do it. Stock just seams to have too much damping for sharp bumps and not enough for rolling bumps. If I get them I'd have to do something about the nasty fork sticktion that it has too. It never ends! The ZRX rear shocks are like night and day difference on the rear.

Z1R rider wrote:

I've toyed with the idea of emulators for my Z1R, but have yet to do it. Stock just seams to have too much damping for sharp bumps and not enough for rolling bumps. If I get them I'd have to do something about the nasty fork sticktion that it has too. It never ends! The ZRX rear shocks are like night and day difference on the rear.

A lot of stiction is not a good thing. You may want to have the forks checked to make sure they aren't warped or bent slightly. Good luck

I just got the race-tech emulators for my KZ650. I should have them installed within the next two weeks and I can let you all know how they work.

I've had valve emulators on my Z1 for about 4 months now. The difference is huge. It's not just dropping in the emulators though (and drilling the damping rods) you need stiffer springs. The stock springs are (too) soft because of the limited damping; the fork would be too harsh with stiff springs.
With the emulators installed and the damping rods drilled you will have more controlled damping, so you can use stiffer springs. Your front end will never feel the same

DrWhizBang wrote:

I just got the race-tech emulators for my KZ650. I should have them installed within the next two weeks and I can let you all know how they work.

What did they run you?
-KR

Vegasvideo,
I really enjoyed that writeup.
-KR

Bad Kaw wrote:

Vegasvideo,
I really enjoyed that writeup.
-KR

Thanks, I should have a video up in a week or so

Bad Kaw wrote:

DrWhizBang wrote:

I just got the race-tech emulators for my KZ650. I should have them installed within the next two weeks and I can let you all know how they work.

What did they run you?
-KR

$149.99 + $9.98 for "adapters" required for proper fitment - direct from Race-Tech. They gave me that price because I found a lower price from another retailer. However, the adapters I could only buy direct from Race-Tech themselves.

Still not assembled yet - paint goes on tonight, so probably some time next week. I just got a new camera (Father's Day so I will try to get some photos.