Guzzi V7 Rear Shock Overhaul

I purchased a set of used rears shocks a long time ago in order to try a rebuild. An overhaul makes totally sense to me because you never know how long shocks have been used without service. Gregory Bender offers some very helpful advice on his website, separated into outer and inner section. I took these information as a guide and did the job a few days ago. This is the description of my experience (using Gregory´s terminology):

OUTER SHOCK – Disassembling the outer shock is not a big deal. You can compress the spring with a compressing tool, remove it and turn/slide the adjusting collar over two small tabs on the outer tube. Just do the same with the two spring cups and the cover tubes. The latter come in plastic or metal – be careful with the plastic ones, they are not very flexible and might break…

You are now able to clean/paint/chrome these parts. But it does not affect the technical quality of the shock. Going any further than that means you need to have a…

SPECIAL TOOL – First, unscrew the seal nut. No, stop – this is a tricky task! Don´t try it with punch and hammer. I ruined one shock with just a few hits and had to destroy it with a saw after heat did not help opening the seal nut either. Instead, take a 6 mm metal plate, drill two holes in it, prepare room for the damper rod and weld two 6×6 mm square metal bars into the holes, using them as fingers for the seal nut. Finally, attach half of an old Guzzi handlebar (or anything else) as a lever to it. It is not necessary but helpful to have a slotted distance tube on top of that tool. This helps keeping your special tool aligned and presses it onto the seal nut.

The tool fabrication alone took me about 3 hours… You better check specific dimensions, distances and depths on your own shocks since they might vary slightly, but my pictures should give you a good guide.

INNER SHOCK – Now, put the shock into a vice and unscrew the seal nut with your lovely tool, using just as much brute force as needed. Be careful and avoid slipping off – you might ruin the soft alloy seal nut and its grooves. BTW: The nut has an ordinary right-hand-thread.

You have now managed the biggest challenge. Then, pull the inner parts out of the outer tube (gentle wobbling plus pulling helps). You will then discover all internal parts: inner tube, complete rod and the orifice assemblies. Unscrew the nut on the end of the damper rod. Now, pull all the tiny bits off the rod. Clean everything with adequate chemicals, such as brake cleaner. Take care of the rubber seals. Replacements are not available – you need to reuse what you have! And, finally, be very careful about how all parts are aligned on the damper rod – keep everything in order and place the bits with either bottom or top on your workbench. Taking photos helps, too. Changing the assembly order or direction of these parts might immediately lead to malfunction.

ASSEMBLY – Cleaning, painting and re-assembling all the bits and pieces is just a question of patience and care – not a big deal. The chromed springs can be cleaned with Luster Lace (my case), or re-chromed when needed. The rest can be painted. Then, insert the orifice assembly 2 at the bottom of the damper. Therefore, you better put it on the standing inner tube (orifice up) and push the outer shock tube over it from above. Make sure that everything sits perfectly in place when turning these parts around again – otherwise the damper will not work. Refill the tubes with fresh damper oil (viscosity 15 seems fine to me) up to the point that you can only see the last centimeter of the inner tube above oil level (when upright). Wait a few minutes, letting air bubbles leave the oil. Then, gently push the inner damping parts plus damper rod into the inner tube while taking care of the rubber seal on the upper orifice assembly (the rubber moved out of place in my case when being pushed into the tube thread).

You should be able to finish the work with screwing the seal nut into place. Some oil might want to disappear through the thread while screwing. But that is OK – Gregory Bender is also writing about this self-leveling… When the seal nut is fully tightened, it should seal the inner parts completely. Finally, check for full movability of the damper rod and add the rest of the damper: 1 spring, 2 cups and the spring collar. Be careful when compressing the spring for the final assembly – my compressing tool scratched the new paint on the freshly sprayed covers when releasing spring load. Thin foam material helps…

MY PROBLEMS – My V7 shocks had two problems: A shim was broken, not providing enough pressure for the oil to pass by. And the damper rod on one shock was bent visibly. This is why I replaced these parts with spares from the Ebay shocks. So I kept my original set on the bike and rebuilt them. Unfortunately, that means that the spare set is no longer usable. But, good luck I had them in stock…!

DIFFERENT VERSIONS – I soon realized that there are small differences regarding the inner layout of the shocks, the outer tube and the orifice assembly. This picture shows what I had on my workbench: (1) and (2) are the shocks from my bike while (3) and (4) are used shocks from Ebay. They are called “L.I.M.S. Felsina” (patents plus logo on outer tube) or “L.I.M.S. Futa” (stamped into upper shock mount). Differences between them are varying orifice assemblies, cover tubes and the rod end, with either a small spring or another orifice assembly at the bottom. LIMS, BTW, was the shock producer back in the days, later providing the “Savena” for the first Guzzi Le Mans…

So, no matter what type of shock you have, just go for the overhaul! The job is really straight forward – WHEN the special tool or an equivalent solution is available! Let me know if I can send/help you out with my tool – it proofed its function and might help you, too…


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s