'96 Skorpion Sport track bike - fork upgrade/setup

[pwillikers]

The MZ Skorp sport has primitive (by today's standards), non-adjustable, damper rod, Paioli front forks and I also believe the previous owner of mine installed heavier fork springs. They've never worked well - harsh in compression and no rebound damping.

I installed Racetech Gold Valves which allow control of compression damping but do nothing for rebound damping, which, with is almost nonexistent. I increased the fork oil weight in steps up to 20wt. and still had no damping. I called Racetech tech support. Tony suggested I braze up the existing rebound hole in the damper rods. They surmised that there might be enough clearance between the damper rod and the bushing through which it slides to control rebound. And if not, I could still drill another hole.

I proceeded down this path, brazing up the existing .144" dia. holes and went for a test ride on a very bumpy road near my house. The forks immediately "packed down" indicating excessive rebound damping. I pulled the damper rods and drilled a .070 dia. hole in each rod (hell of a laborious way to adjust damping) installed some 5 wt. oil, buttoned it up and took it for a ride. Big improvement. In my short ride, it seems to be nicely improved with smooth and controlled rebound. It's cold and raining now so I'll have to wait for better weather to try it out for sure but it seems to have worked. I've reduced the area through which the oil flows on rebound to 25% of it's original size. Big change.

[Wonky]

The late R6 forks fit direct into the Skorpion! These forks obviously will transform the front end and allow fitment of R6 front wheel and brake set-up. A much better approach to improving handling and won't hurt your bank balance too much!

[ZzerO]

hi wonky

what year of R6 do you mean? and is it the entire fork or just the 'legs' that can be mounted, so you can use the original yokes?

greetz patrick

[steveweck]

I replaced my complete front end with an 01 R1 front end on my Skorpion Sport. The triple clamp is wider so I had to trim a little bit of the bottom of the fairing and the clip-ons were to close to the sides of the fairing as well. I just trimmed it a little as well. Looks great. This is a race bike so I'm using Beasley fiberglass bodywork. Cutting stock plastic is a different story. I also needed to tack on a slightly bigger steering stop on the frame. To get the R1 triple clamp to fit I just had to replace the bearings. I had to measure the diameter of the R1 stem and the inside diameter of the steering head of the frame. Also the hieght of the stock bearings. A call to All Balls Bearings and 3 days later I had them and installed everything in a couple of hours. You'll need to remove the old races from the frame. You'll also need to heat up the bottom bearing to fit on the stem.

Steve

[Wonky]

[ZzerO]

haha dont think I can afford a brand new front end right now

but you mean that nothing has to be changed, not even bearings? hehe thats funny, must be a good upgrade for a skorpion!

do you perhaps have a picture of this kinda mod? i'm sure it looks hot!

greetz

[Wonky]

I will have next year buddy! I haven't done it yet but i know a man who has!!!! I'm going to be building a road going MZ Factory Supermono Replica....need to finish my other bike first! And yes apparently it looks awesome and we couldn't believe they fitted either....

[pwillikers]

Alright Mr. Wonky, I'll bite. How much for a complete yammie front end including controls, wheel, calipers, rotors etc?

[Wonky]

I will have to contact my supplier next week, Tuesday, if he doesn't answer tomorrow as i'm going into the workshop to carry on with the ST MZ project. I will then give you a price complete with shipping. Sit tight and i'll keep you posted.

[hb7]

Paul ....did you drill the necessary 4-6 ~8-10mm holes in the dampers ?

The racetech emulator with upgraded springs in the Paoli forks works very well..if you ask me. I run 7.5wt ATF oil.

[pwillikers]

Yes, as per the Racetech instruction, I drilled large holes in the bottom of the damper rods to short circuit the stock compression damping and allow the gold valves to do the entire compression damping job.

You like your forks now! Great to know that there's hope . Please recount details of your setup.

I thought I should include here all the stuff I've done so far. In addition to the aforementioned heavier springs, gold valves and 5wt. oil, here are pics of the damper rod rebound hole mods.

Originall damper rod w/.144" dia. rebound hole (so sad):


Brazed and drilled damper rod w/.070" dia. rebound hole (very happy):

[pwillikers]

This is a cross post from the 660 forum: I asked that all responses be posted in this thread.

For you track guys, I've got a question on fork setup.

In tight turns (Texas World Speedway Turn 10, for example) I have to constantly weight the inside peg and or lean on the inside clipon (not a prefered method) to maintain the tight line. I've raised the fork tubes 5 then 10 then 15mm (tube showing above the clipon) in an attempt to make it easier to steer without all the effort. Raising the fork tubes has helped alot. Holding tighter lines is definitely easier and improved toward neutral handling (where no weighting or countersteering would be needed to maintain the line), but it still needs to be improved. I haven't yet sensed any tendency towards instability or twichyness. Maybe I should just keep raising the tubes 'til I run the front fender into the radiator or it gets twichy? Not sure how far I can go in this direction.

How far are your fork tubes raised? Were you able to eliminate this handling problem?

[hb7]

I'm just a traffic splitting street rider....so I kept the stock 30mm fork height above the the triple. I weigh 165lbs and carry cargo ~25lbs. I have .95 springs which were very stiff at first, but then seem to settle in after a month. I have the top damper hole brazed up.

I do not see your big 10mm holes in your damper photos....?
Are you using a ~10mm spacer for the emulator above the damper ?

[pwillikers]

Do you really mean 30mm above the triple clamp or above the clipon?

I don't have a pic of the bottom of the damper rods. Believe me, there are six 1/4 in holes in each rod.

I made a PVC spacer to go between the damper rod and the gold valve (GV). I machined the surfaces really smooooth so it seals very tightly against both mating surfaces - so much so that the surface tension from the fork oil holds all three pieces together.

The model GV I used is for early model SV650 Suzukis, #FEGV S4101. Is this the model you used? How many turns down from "free" did you tighten the spring tension on the GV?

[hb7]

3 turns from free.
15mm of spring preload spacers for 35x340x.95kg/mm spring
30mm above the triple clamp.
#FEGV S4101 correct...