Hi All,

I would like to improve the Marzocchi 38mm air assisted fork that came standard on my 1985 750F1.

Is it a good idea to install in it a Racetech Gold valve emulator ?

Any suggestion to improve my non adjustable fork ? (I will not install a japanese fork).

Thanks for your input.

Gilles Lachance

Hi Gilles,
I would recommend contacting Race Tech directly. I have found them to be very helpful over the phone when I rebuilt and modified a set of R90s forks a couple years ago to their instructions, which included Gold Valves, and am very happy with the results. I have also been in contact with them about a set of Norton Commando forks recently, which are not suitable for Gold Valves, but they were very helpful with spring selection and other fork tuning advice.
Bill

From their website:
"If your bike is not listed in our Product Search, you have questions about applications or setup please Email Matthew Wiley for Vintage Tech Support/R&D.
Matt can also be reached at 951-279-6655 ext# 108 during regular business hours PST Monday - Friday."

Hi Gilles,

I can recommend this manufacturer - have the kit in the TT2 as well as in other motorcycles

http://www.hh-racetech.de/HH-Race-Tech- ... hi-Paioli/

maybe a bit complicated because of the long distance (shipping/customs) but worth the effort.

The fork is now full adjustable

Regards

Wolf

I have been waiting until the new year to unload my exiting new venture on the forum, but in reply to this thread I will bring it forward to today.

We all know the Race tech emulators well. I have lost count of the number I have fitted to customers forks over the years.

However, I have always been frustrated by a few things. They execute control of the compression damping but do nothing at all for the rebound, relying on the customer to change the oil weight to effect an adjustment. Also they need to be removed from the fork assembly to make an adjustment to he compression damping. A very oily messy job, and one which historically I have found the customer doesn't do more than twice for this very reason.

With the above issues in mind I have designed and developed a new style of fork valve. It fits under the main spring on top of the piston rod in much the same way as the traditional emulator. It has the usual adjustable compression damping, but additionally has 30 clicks of rebound damping adjustment. The really good part is the fact the valve adjustment is simply accessed by a long concentric special tool passed through a blanking plug hole made in the fork cap, fed down past the main spring and onto the valve to make any adjustments. This is easily done in less than a minute with little or no oil loss.
It is designed to use thinner oil too. I am using either 2.5 or 5w oil.

I first put them in 'Baby' the TT2 which Chris races. He went round Taupo 2 seconds faster immediately, reporting it felt much more 'planted' allowing him to use different lines. With a few minor adjustments to the valves we improved matters even further, resulting in yet another second off the lap times.

A number of guys are now using them here in NZ on all sorts of classic race bikes, all with good reports.

The sizing is important. I need an accurate measurement of the stanchion bore to within 0.1mm. Some simple drilling is required to the existing damper rod. Some holes to drill out and fill some others in. So they are easy to fit and most guys will be able to do it in the workshop at home.

They will be available in the new year. $450 nz per kit (For a pair of valves including the adjusting tool) plus shipping.

I have been dealing with a patent application for some months but am now in a position to shout about it.

it is exactly like Glyn wrote, the adjusting of the Gold Valve (which is a fine invention) is very oily - this is the reason why I have choosen the fork conversion I mentioned before.

I tested the Gold Valve in the fork of my bevel 900SS with a complete new build internal but I didn't like the dismantling process to do the adjustment. The new internals consisted of a new build damping rod and piston made out of high tensile aluminum, fasteners made out of titanium. Weight including the Gold Valve was below the weight of the Marzocchi setup.

Now my old setup is used by a friend, who is rather happy with it, obviously he is not that sensitive working with oily hands

Cheers

Wolf

Hi Gilles, Looking at the picture of the damper rods you may have a problem there.

I am looking at the series of holes drilled in the lower damper rod needed for the Race tech emulator to work. They seem as though they may extend upwards on the damper rod beyond the check valve under full compression. This will not affect the compression damping at all, but will cause an issue on the rebound stroke. The oil will flow through these holes directly back to the bore of the damper rod for a period at the bottom end of the stroke rather than only through the upper (very small) rebound holes. This will result in no effective rebound damping on this portion of the return stroke until these holes have back passed below the check valve. Please check this out.

As long as the sum of the surface area of all the lower holes are greater than the bore of the damper rod tube , that is as large as they ever need to be, as after that point the bore of the rod itself will become the oil passage restriction in the system flow, not the holes.

Hope that all makes sense, because it's getting a little late here and I have a generous glass of rum beside me.

the gold valves worked quite well in my 851 m1r. still crap by modern standards, but much better.

very annoying to adjust though.

Hi Gilles The question is relevant to the application of the bike. First start out with proper fork spring rates and oil viscosity and height. I would try progressive springs with this fork. For the street that might be good enough. For hard street riding and racetrack it probably won’t be. Emulators will help here. I have used them and also modified them with my own rebound valve. I commend Glyn for taking that on as well. I have also adapted Ricor valves that seem to work better than the Racetech unites. http://store.ricorshocks.com/default.asp
In the end you will find the old style small size fork that have no slide bushings will be the limiting factor for all out performance. Maybe the cheapest route that would stay in line with original is fit the FI units from the later F1?
--Cranky-

Hi Glyn,

the dimensions of the holes wher inspired by this website - since information on the installation was at the time I did it was scarce I transferred the hole dimensions on my damping rods...please feel free to point me in the right direction what may be done to improve the setup

Wolf

Glyn's proposition seems a good one. Considering that his version of fork emulators comes with the adjusting tool, the asked price (450 $NZ) seems correct when converted in US dollars (298 $US) or canadian dollars (399 $can).

Hey Glyn, could you post some photos of your emulator ?

And it would allow me to keep using my 38mm Marzocchi fork.

I am not an expert, but I believe a 38mm fork is enough for a F1 in racing trim, considering that my bike will weight no more than 300-310 pounds with the new 17 in. Marvic magnesium wheels (and race tires) that are presently on their way to my home thanks to Fred Renz (Yoyodyne) and the Marvic factory who accepted to produce a 5 in. width rear wheel by special order.

Gilles