This time we will take care of one of the, I think, most NOT recommended to do on your own procedures. But who doesn’t like some challenge! Let’s start unscrewing and see how it goes :)

Which DR350 rear shock model we will rebuild today?

As far as I’ve researched, there were (at least) three rear shock models mounted to DRs.

The first one was fitted to the dirt versions of DRs and had both the rebound and compression dampening adjustments. Later similar shock was mounted on street legal DRs (DR350SE), which left the factories from 1997 to 1998.
The second DR350 rear shock model was very similar to the dirt one and was mounted to the street legal models produced from 1990 to 1993.  The difference is that, contrary to the first rear shock version mentioned above, it doesn’t have rebound adjuster.
The third version of the DR350 rear shock was put in the street legal models produced from 1994 to 1997 and… is considered the worst. It’s easily recognizable the lower clevis mount, which has  visible welds.

Today we will disassemble a 90-93S rear shock. But I think the procedure should be quite similar to the other models. Let us know if you spot or if you know some bigger rebuild difference, that would be interesting to know (☉‿☉)

The first dismantling steps

Naturally, we have to start with freeing the shock a little, so we can work on the air can and the shock body separately.

First we take apart the air can handle by removing two clamps, which are holding it.

Removing air can handle from the rear shock

Removing the air can handles

Next we can unscrew the spring preload adjuster locking ring. It will probably be a little stuck, so we can go for it and use a hammer with a punch tool, though gently ;)

Preload adjuster locking ring removal from the rear shock of DR350S

Preload adjuster locking ring removal

In my case the nut was seized, so I also used a penetrating oil.

Using penetrating oil on the preload adjuster locking ring

Good old WD-40…

When it’s  finally loosened, we unscrewed it together with the spring preload adjuster.

Uncrewing the nut and the spring preload adjuster

Unscrewing the nut and the spring preload adjuster

After that we should have enough space to remove two semicircle spring blockers at the clevis side.

Removing spring blockers

Removing spring blockers

When the blockers are gone, we can release the spring.

Rear shock spring disassemble in DR350

First the collar…

Removing spring during rear shock rebuild for DR350

And then the spring

Finally we can remove the spring preload adjuster locking ring and the spring preload adjuster.

Spring preload adjuster removal from the rear shock of DR350

Unscrew down until it gets off the shock body

Disassembling the air can

After those first dismantling steps, we can take care of the air can now.

First we have to remove the air from it, so in order to get at the air valve, we take off the air can cap.

Removing the air can cap from the rear shock of DR350

A gentle prizing with a screwdriver should suffice

The air valve you’ll find under the cap is a standard one, so we just unscrew the air valve cap and push the valve core in.

Unscrewing the air valve in the rear shock air can of DR350

Just unscrew…

Pushing the air valve in the air can of the rear shock of Suzuki DR350

And push

Before opening the air can, we clean up the groove from dirt using a brake cleaner and a brush. In the end I’ve also used compressed air to limit the probability that some sand will come into the can. It may be hard to then turn it out from the can (╯︵╰,)

Cleaning air can opening during the rear shock rebuild for Suzuki DR350

Applying some break cleaner

Cleaning air can opening with compressed air during the rear shock rebuild of Suzuki DR350

Getting rid of sand with compressed air

When the cleaning is done, in order to open the can, we push the cover with valve inside it.

Opening the rear shock air can with a hammer

You may need to use some hammer help in the beginning

If you decide that you also need a hammer for this step, then be gentle. You only want to make it more easy to push further with hands.

Opening the air can with hands - rear shock rebuild of DR350

Now we can utilize our precious hands

After pressing the cover a little, it’s good to release the pressure by opening the valve. It will be easier to push the cover further.

Releasing the prssure in the air can

Just push the valve core in again

When the cover securing ring in its groove is visible and there is enough space to remove it, then we can stop wrestling with the cap. The cap will be released when we get rid of the ring.

The air can cover securing ring in the rear shock of DR350

The securing ring for which we are looking for

I used a small flat screwdriver and a thin metal plate for this.

Removing air can cap securing ring

I prized the ring with a common feeler gauge

Now we have to pull the cover back out. The simplest way to do it is just to connect an air pump to the valve and pump some air inside.
It should pop out by itself.

Opening the air can cover with pumped air

Just a little pumping…

Opening the air can cover with pumped air

And it’s done!

Now as the can is open, we can take out the rubber sleeve sitting there and pour out the old, nasty looking oil

Taking out the air can rubber sleeve during the rear shock rebuild of DR350

Out you go, sleeve

Pouring out the old oil for the air can of the DR350

Blargh!

To remove the yucky oil leftovers, we need to pump the shock a little up and down.

Removing the old oil leftovers from the air can during the rear shock rebuild for DR350

Got to use some strength ᕙ(・‿‿・)ᕗ

Removing the old oil leftovers from the air can during the rear shock rebuild for DR350

Or find someone stronger ᕙ(・﹏・)ᕗ

Taking the compression adjuster into parts

Next we remove the compression adjuster.

Unscrewing the compression adjuster during reaar shock rebuild for DR350

Unscrewing the compression adjuster

Unscrewing the compression adjuster during reaar shock rebuild for DR350

Here’s how the adjuster looks like at first sight…

But! Be careful, as there should be two additional pieces of one way valve inside the air can and it’s better not to lose it. Make sure you take them out too. Here you can see all pieces you should collect at this step ;)

Suzuki DR350 compression adjuster

All the parts you should find

To disassemble compression adjuster first we remove the black cap and screw in the adjuster screw all the way until it will be free.

Compression adjuster disassembly for DR350 rear shock rebuild

Here’s the black cap off the adjuster

Compression adjuster disassembly for DR350 rear shock rebuild

Now we screw in the only screw we’ve got there

Compression adjuster disassembly for DR350 rear shock rebuild

And it’s freed

Now we have just some cleaning left. For the the air can I used the brake cleaner again. For other parts – I used an engine cleaner.

Cleaning the rear shock during rebuild

Using break cleaner for the air can parts

Cleaning the rear shock during rebuild

For other parts I used an engine cleaner

Cleaning the rear shock during rebuild

Spring had bath in engine cleaner too

Disassembling the shock cylinder body

Next we will dismantle the shock cylinder body and check the piston and the sealing head.
First we need to remove the tube cap. As you will see below, I just put a drill bit in the small hole in the cap and gently punch it with a hammer.

Removing tube cap from the rear shock cylinder body of DR350

Putting the drill bit in place

Removing tube cap from the rear shock cylinder body

And now few gentle hits

Removing tube cap from the rear shock cylinder body

Voila

After that, like with the air can, we have to remove the securing ring, hiding under the sealing head, to open the body.
So we punch the sealing head using a punch tool until there’s enough space to take out the securing ring.

Removing the DR350 rear shock cylinder body securing ring

Hit gently and evenly across the surface

Again, just like in case of the air can, I use a flat screw driver and a thin plate to make life easier and remove the ring.

Removing the rear shock cylinder body securing ring

A little screwdriver help to get around the ring

Next we slide the piston up and down to pull out the sealing head. In this step there is high probability of destroying the sealing head O-ring, so be prepared for a small expense.

Removing the rear shock cylinder body sealing head

Some more force required in this up and down sliding step

Removing the rear shock cylinder body sealing head for DR350

And it’s out

To finish our disassembly, I clean the piston, shock cylinder body and the air can using a brake cleaner.

Now the only this left is inspecting the sealing head O-ring.

Taking off the damaged O-ring from the rear shock sealing head

Taking the O-ring off

Rear shock sealing head O-ring inspection

It’s damaged :(

As you can see we cut off a small piece of it. So wee will now replace it with a new one.

Rear shock sealing head O-ring replacement

Fortunately, we were prepared

Assembling the rear shock cylinder body back together

Now only the shock assembly is left ᕕ(☉‿☉)ᕗ

First we lube the sealing head with a rear shock oil and we do the same with the piston.

Lubing the cylinder durring rear shock assembly for DR350S

The cylinder

Lubing the piston durring rear shock assembly for DR350S

And then the piston

After that we can insert piston and cylinder head back into the tube.

Inserting the cylinder into the body during rear shock assembly for DR350S

Inserting piston into the body

Then comes the securing ring. (Remember to make sure it is sitting well in its groove.)

Inserting the securing ring into the DR350 rear shock body

Putting the securing ring back

After that we draw back the piston all the way up to lock the sealing head in its place.

Blocking the sealing head in its place

Blocking the sealing head

Next we put back the cover using hammer.

Putting back the DR350 rear shock cylinder body cover

Don’t be too harsh with the hammer

Putting back the cylinder body cover

In the end cover looks like this

Assembling the compression adjuster

For now we’re done with the body. So we can put back together the compression adjuster.
Before assembling the adjuster screw we lube its O-ring with oil.

Compression adjuster screw O-ring lube during rear shock air can assembly

A little oil will only help

Compression adjuster screw O-ring lube during rear shock air can assembly

Now we slide the screw back in

Compression adjuster screw assembly during DR350 rear shock air can assembly

And use a screwdriver

Next we put back the black cap using a socket and a hammer to lock it in it’s place.

Putting back the black cap on the DR350 compression adjuster

Bare hands would unlikely be sufficient here

Putting back the black cap on the DR350 compression adjuster

So we again make friends with the hammer

Putting back the black cap on the DR350 compression adjuster

And its ready

After that we put in the one way valve into the air can.

Assembling one way valve into the air can - DR350S rear shock rebuild

Our valve parts

First we insert the washer on the pic below. It’s important to place it with its groove upwards.

Assembling one way valve into the rear shock air can of the DR350S

This guy goes first. Pay attention to the groove

Assembling one way valve into the rear shock air can of DR350S

The groove goes upwards

As you might guessed, next we put the smaller metal washer inside this groove.

Assembling one way valve into the rear shock air can

Now the smaller fellow goes in

Assembling one way valve into the air can

In the end the valve inside looks like this

Because the one way valve is inside, we can put back in the compression adjuster.
So, naturally, we lube the adjuster O-ring with oil and screw the adjuster back to the air can.

Screwing back in the compression adjuster

Putting some oil…

Finally, the last touch – we lock the adjuster thread using a point punch.

Locking the rear shock compression adjuster with a punch tool and a hammer

Now it should stay in place

Filling the oil and air

Now we are ready for pouring in the fresh oil to the can.

Filling the DR350 rear shock with fresh oil

Drink! ᕕ(☉‿☉)ᕗ

But we don’t immediately put back the rubber sleeve. First we pump the shock until we remove all of the air bubbles from the oil chamber. If need be – we pour some more oil.

Removing air bubbles form the rear shock oil chamber

Removing the air bubbles

In the end you should not see any little bubble coming  out during the shock compression.

After that we fill the whole can with oil up to its edge and insert the rubber sleeve.

Pouring oil to full to the rear shock oil chamber

Don’t stint the oil, be generous ヽ(☉‿☉)ノ

Inserting the rubber sleeve into the rear shock air can

Inserting the rubber sleeve. The oil will spill out so be prepared

Next we push the air can cap inside the air can until there will be enough space to insert the securing ring.

Putting back rear shock air can securing ring

Putting back rear shock air can securing ring

Now we should pump some air inside the air can air chamber.
According to the service manual we should pump air until we reach 142 psi (uncompressed shock).

Rear shock absorber pressure from the DR350S service manual

Snippet from the service manual

So we just connect an ordinary pump to the air can air valve and pump until we reach the value recommended by Mr Suzuki.

Filling the rear shock air chamber with air

Filling the rear shock air chamber with air

Filling the rear shock air chamber with air - result

Results

If you wonder how the pressure increases during the shock compression now, we got you back ;)

Filling the rear shock air chamber with air - result during shock compression

Results during maximum shock compression

Finally we are ready to put back the air valve cap and the air can cap.

Putting back the rear shock air can cap

Putting back the air can cap

The last step is putting the spring back.
So first we screw back the adjuster nut and the locking ring.

Putting adjuster nut back on the rear shock body

Putting back the adjuster nut

Putting locking ring back on the rear shock body

And now the locking ring

Putting locking ring back on the rear shock body

Screw it in loosely, we will adjust this in a minute

Finally we put back the spring and the top spring collar.

Putting on the rear shock spring back

Putting on the rear shock spring back

Inserting the spring collar back

Inserting the spring collar

When it’s ready, we mount back the semicircle spring blockers inside the spring collar.

Installing the rear shock spring blockers

Installing the rear shock spring blockers

Now what’s left is setting the spring length using the preload adjuster. I set my spring to standard length, that is, 269.2 mm

DR350S service manual about spring preload adjustment

What the manual says about the preload adjustment

So we screw in  adjuster  and its locking ring until the spring will reach the desired dimension.

Rear shock preload adjustment result

Preload adjustment result

When we have the proper spring length, then we can lock it by locking the spring adjuster ring with a punch tool.

Locking the rear shock spring

Locking the spring

Now we put back the air can handle by tightening it in position with two clamps…

Putting back the rear shock air can handles

Putting back the air can handles

And we’re done! Congratulations ʕ•ᴥ•ʔ Our DR350 rear shock is ready for some tough riding again ᕙ(◉‿◉)ᕗ

Ready DR350 rear shock

Ready!

If you feel like something’s missing here, let us now! \(ᴗ‿ᴗ)/

And if you more like in the TL;DR mode today (or any day :P) you can also check our video below, which also covers the whole procedure of the DR350 rear shock rebuilding:

Ride safe! :)