Front End Born Again!

VMAX  Forum

Help Support VMAX Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

scottybaccus

Active Member
Joined
Sep 26, 2013
Messages
33
Reaction score
0
Location
Hutto
I was planning a play by play when I did the install, but it was a comedy of errors, so here's a run down of the meaningful part.

My 2003 Vmax had about 4200 miles on it when I purchased it. While it had no crash history, it did have tale tale signs that it had fallen over in the garage or something. It came with a service receipt for fork seals, among other things, but still had indications that one was leaking. I put up with this for about 4000 miles while I prioritized other changes. In the end, I decided to install a Progressive lowering kit and Race Tech emulators when I replaced the seals.

Part numbers- Progressive 10-1563 & Race Tech FEGV S4301
Both are advertised as "drop-in". Not quite.

If you drop the RT emulators into stock forks, you should just need to trim the thickness of the emulator valve from the spacer above the spring. Drill some holes in the damping rod to shift control of damping to the emulator, and drop the valve in on top of the damping rod. More on that in a sec.
If you use the Progressive kit without the emulators, you swap out springs, above and below the damping rod, add extra springs for 1-2 inches of drop, and cut spacers to a prescribed length. This is pretty straight forward, so back to the emulators....

The emulator is supposed to sit on the top surface of the damping rod. The damping rod has a flat seat that is where the spring ordinarily sits. Installed, the spring now sits on the emulator, and the emulator sits on the damping rod. The damping rod is tubular, and has a couple of sets of holes. Each is very purposeful. A tiny hole up high is a rebound restriction. Leave it alone. A pair of bigger holes at the bottom are the compression restriction. These get enlarged, and additional holes added (follow instructions here) so that the deciding factor on fork behavior is no longer the compression holes, but the emulator valving. For the emulator to do it's job, you don't want any fluid leaks to bypass the emulator through a gap between the damping rod and the emulator. Race Tech does this by machining a shoulder on the emulator that should fit, with very little clearance, into the I.D. of the damping rod. Guess what.... In my case, it doesn't. I understand that this is an issue with all of the 43mm forks used on the Vmax. I have no info on the early models. So, how is this resolved? Race Tech says "Oh yea! You need an adapter!" It turns out they sell one, but a couple of calls and some reading reveal it's really just a precisely machined tube about 15mm long. It must be very square so that the emulator isn't cocked at an angle that might cause wear inside the fork tube or allow a fluid leak. The shoulder on the emulator indexes the emulator to keep it centered, too. The spacer allows nothing like that. I don't know about you, but I don't usually settle for band-aid engineering. I decided to machine an aluminum spacer that provided a shoulder of proper diameter to index on the damping rod, but also a recess large enough to index the emulator. Imagine a funnel inside a cylinder. The I.D. matches the damping rod so as to prevent restriction, otherwise it centers the emulator and provides a square seat for the spring with no opportunity for fluid to squeeze out between the components.
Back to installing all this, Sean Morley's videos are precisely what you need to know for the lowering kit. The emulator instructions are very straight forward about how to modify the damping rod, and then you just need to "drop-in" the emulator above the damping rod, then drop in the spring and the spacer. The spacer length is prescribed in the Progressive kit, but now you need to subtract the thickness of the emulator and spacer. Keep in mind, this is a starting point for preload that you will need to dial in through trial and error. Careful measuring is important, and the pvc tubing must be cut squarely. A tubing cutter is key here. Buy one made for pvc, but not a shear or scissors. get the wheel and spin-it type.
Another note on tuning. The emulators are adjustable! Anyone that tried 'em/hated 'em didn't bother tuning them. The starting recommendations in the instructions are decent.
So here is my set-up:
I used the kits listed above, drilled the damping rods as instructed, cleaning and chamfering the holes carefully. I used the 1" option on the lowering kit, which adds a top-out spring below the damping rod. I used the BG synthetic power steering fluid that Sean suggests, at the factory level (measured before emulator/spring/spacer are installed). My emulator spacer means there is no point in describing spacer length, so focus on preload measurements. I started with the suggested max, comparing what both companies recommend, but failed to measure properly, do the math, yada, yada. I almost didn't get the caps installed. Revisited the next day, I discovered that the springs had settled a bit overnight and that a math correction really made things work nicely. I made a trial run, then came back and took 1/4" off the spacers. (I cut a second pair, actually, thinking I might want to swap back). The emulator tune includes the yellow 64lb spring, set to 1.030". I doubt that the last .030 matters, but you want both sides equal. This is about 4 turns. There are a lot of ways you can tune these, so read up and study!

Results! The transformation was remarkable! It is a bit stiff for the street, but amazing on nice pavement. I may back of the emulator spring by a half turn and/or the main spring preload by another 1/4". The neat thing is that as you begin to get acquainted with the bike's new manners, you begin to notice the issues on the rear that were muddled in with the front before. I found that it prompted me to increase the rebound damping on the rear shocks (I have preload maxed), and it completely settled down. The rear shocks work better than I had realized. They will go away soon, but it's not as high on the list any more....

There's a link at the bottom of this page to a photo of the emulator spacer that I made up. (Actually, I drew it in CAD and my buddies did the machine work) If anyone wants, i can get them to quote additional sets. If any demand, i might get them to make a small run of them.

In the end, I opted out of spending the cash on USD forks, and renewed the fork seals and transformed their function for about $300. Best money spent so far! In second place? My UFO pipe and jetting. Rear shocks and some restyling are coming soon.


https://www.facebook.com/TejasSteelWorks/photos/a.439344049449728.112013.369598079757659/734122143305249/?type=1&theater
 
How much for a pair of the spacers? I'll be putting the valves in with racetech springs into my 43mm forks.
 
Last edited:
I have roughly the same setup, albeit with 41mm forks, Ricor Intiminator valves, Progressive springs with 1" lowering springs, 5 wt Silkolene fork oil and Sean's top caps which allow for external spring rate adjustment.
Like your results, this transformed the front end and coupled with my Progressive 440's, Carrozzeria's with radial rubber, a braced and extended swingarm, and solid motor mounts the bike handles 1000% better.
The Ricor Intiminators and Progressive 440's have a similar suspension operation in that they differentiate between how they handle the wheel hitting a pot hole and pushing up the suspension or if the chassis is pushing down on the suspension. Here is some documentation on the theory behind a Inertia Active Suspension system:
http://store.ricorshocks.com/ias_technology_s/19.htm
http://www.youtube.com/watch?v=j8gv3bGbzGM
 
Rob, I'll find out.

Mars, you may not need them.

Redbone, I had seen that before. Good stuff. I am headed down the same path as you.
 
Rob, If I can get a few orders, I can do them at $35 a set, plus postage. I need to have ten sets made to manage that price. Compared to the simple spacers that Race Tech sells for $20 plus UPS shipping, that's a deal!

email me at [email protected] if you're interested.
 
If you're still looking for interest in the spacers, I'll take a set. I'm not sure when I'll be doing my front end work, but it wouldn't hurt to have the spacers ready to go...
 
Cool. I'll see about getting a small run going when I get back in the shop after the 4th of July.
 
Back
Top