Oil Change: Dry-Sump Suzuki DR350 Enduro

Now that I’d checked and adjusted the valves on the DR350, it was a good time to change the oil. Unlike the previous bikes and scooter we’ve seen in this series, this bike has a dry-sump engine, common in dirtbikes and dual-sports.

Dry-sump designs store most of their oil in a tank separate from the engine, and use multi-stage pumps and oil lines to circulate the oil through the motor: in the case of this little Suzuki, the oil tank is actually the hollow steel frame of the bike itself. While more complex than a conventional wet sump engine, they offer a larger oil capacity, better temperature control of the oil, and more places for oil filtration; with no low-hanging oil pan, the engine can also be placed lower in the frame, allowing a lower center of gravity for good cornering. In a conventional wet sump engine, the majority of the oil collects in a large oil sump pan below the engine itself, and is pulled from the pan through an oil pickup tube and circulated through the engine via a large oil pump.

Whatever the engine design, oil, as I’ve said before, is the lifeblood of the engine. I rolled out the bike…

DR350, ready for its oil change DR350, ready for its oil change

Gathered up my tools…

Tools and supplies, organized and easy to grab Tools and supplies, organized and easy to grab

And set things up to be clean, neat and under control with cardboard and my oil pan. Doing an oil change on a dry-sump engine is a bit more involved than a wet-sump variety, but good prep and readiness help make things easier.

(Find out how to get free oil and filter drainer gear and recycle your oil and filters in San Mateo County, San Francisco, Alameda County, Sonoma County, Napa County, Marin County and Sacramento.)

Cardboard and a Riders Recycle drain pan ready to go Cardboard and a Riders Recycle drain pan ready to go

In order to reach the oil pan and oil line bolts, it’s best to remove the skid plate, so I started there.

First, pull off the skid plate First, pull off the skid plate

All at once, the skid plate was off.

Skid plate, removed Skid plate, removed

Next, I looked for the familiar drain bolt on the bottom of the engine crankcase, using my socket wrench and 14mm socket, and removed it. Never mind the broken foot and the peg leg I’m wearing–the oil must be changed!

Removing drain bolt

Drain bolt removal

I was careful to keep the oil pan under the drain hole, of course, when I removed the bolt to release the oil.

Here comes the oil!

The drain bolt, and old crush washer, which I replaced with a new one.

Drain bolt and crush washer

The next step was to drain the oil in the frame. I put a 12mm socket on my wrench and removed the drain bolt, allowing it to drain.

Frame drain bolt

I removed the oil hose clamp, and wiggled the main oil line off.

Removing oil hose clamp

Pulling the oil hose

With the frame draining and the main oil line off, the oil strainer bolt was exposed.

Frame drain bolt removed, main oil line removed

The main oil line is attached to the oil strainer; once the line is removed, the 19mm nut is exposed. It’s torqued on pretty firmly, but I eventually broke it loose.

Removing oil drainer

Removing oil strainer

The oil strainer should be inspected for particles (fortunately there were none), and cleaned. I wiped mine off with a rag and sprayed it with all-purpose solvent, then let it dry.

Oil strainer

The oil filter was my next stop. A plate on the right side of the engine protects the oil filter beneath. I removed the 8mm bolts.

Removing bolts from oil filter cover

The plate has a spring beneath it, so I held the plate pressed against the engine while I removed the rest of the bolts, so the plate wouldn’t bounce off before all the bolts were out.

Oil filter cover--hold the plate

When the plate was off, I inspected its o-ring for cracks, flat spots and wear that might cause leaks.

Oil filter cover plate and spring

Setting the plate aside carefully, I removed the old oil filter, noting its orientation as I removed it.

Removing the old filter

I stuck the old filter in my Riders Recycle drain container (come to one of our events to get one) and left it to drain. I’ll take them to my local recycling place soon.

Placing oil filter in drainer

The new filter, ready to go.

New filter

I placed the new filter on the oil filter boss, in the same direction as the old one.

In goes the new filter

Replacing the oil filter plate

I held the plate again, to prevent the spring from pushing it off, and replaced the 8mm bolts. These are very small bolts, easy to strip or break, so don’t overtighten them!


I wanted to clean everything up after making an oily mess, so I sprayed Winzer’s MPS-100, a general-purpose solvent, over the oily and dirty surfaces then wiped them down.

Spraying cleaning solvent on oily surfaces

The new filter came with a handy tag to note the mileage at the oil change, and the mileage when the next one was due; for a dirt-use dualsport like this one, I like to change the oil every 1500 miles or so when ridden hard. I keep a maintenance spreadsheet for this bike, so I elected not to use the tag.

Mileage tag

With everything drained and cleaned and a new filter in place, it was time to button the bike back up. Note that there is no oil pan, simply the bottom of the crankcase. This means it’s important not to strip the threads, as there is no oil pan to remove and repair!

oil drips from the bottom of the crankcase

I replaced the oil drain bolt (with its fresh crush washer) first.

14mm socket for oil drain bolt

Replacing drain bolt

Next, I re-inserted the oil screen into the frame and tightened it down well. I slipped the main oil line hose back over its fitting, and screwed the clamp down firmly.

Replacing the main oil hose clamp

After this, I replaced the 12mm oil frame drain bolt. The bike was now ready for fresh oil.

For motorcycles, full synthetic is nice, but not necessary. I use conventional “dino” oil on this bike, 10w40 weight as called for in the manual. When buying conventional oil, look for the roundel on the back–the bottom section of the circle should be EMPTY. If it is not, it has additives that are useful for car engines, but will make the bike’s clutch slip and possibly cause additional damage.

Conventional 10w40 oil

Looking at the API roundel–note the empty bottom circle. It’s fine for use in motorcycles.

API Roundel

Oil is both checked and added, on this bike, from a check and filler hole between the handlebars and gas tank. I removed the oil dipstick and set it aside.

Oil dipstick and filler hole

Removing the dipstick so that I can add oil

Then I checked the manual for the bike’s oil capacity–1900 ml. I opened up my Riders Recycle funnel (we give these away at our events, too) and proceeded to add oil.

Riders Recycle funnel

Adding oil

When I’d added about 1500 ml, I stopped, re-inserted the dipstick, and asked my trusty assistant to kick start the bike. I wanted there to be enough oil to protect the engine, but not so much that it would be overfilled; better to add more than to have to drain some out from the frame and sump. This bike, too, needs to be warm to get an accurate dipstick reading.


Once the bike had run for a few minutes and was warm, I stopped it, waited 2 minutes for all to cool down, and checked the dipstick.

Checking the dipstick after warming up the bike

The oil level was, as I expected, slightly low, so I added 400 ml more, then closed up the dipstick, had my buddy kickstart the bike, and checked the oil again. At last, the dipstick indicator had oil up to the top of the hash marks, showing that the oil was full (the oil is so clear it’s tough to see in the photo, but it’s there.)

The oil was full, the bike was clean and buttoned up, and it was time for a ride! Too bad I have a little more healing to do before I can ride…

Dipstick fill indicator</a

My drain pan with its old oil and my filter container, with dirty filter. They were ready to take to me local retail auto shop for recycling. With these, recycling is quick, easy and clean.

Recycling pan and filter drainer, ready to go

Here’s hoping this instructional inspires you to do your own DIY oil change. Find out how to easily recycle your used oil and filters in San Mateo County, San Francisco, Alameda County, Sonoma County, Napa County, Marin County and Sacramento. If you’re not in those counties, find your own convenient oil and filter recycling location HERE.

7 thoughts on “Oil Change: Dry-Sump Suzuki DR350 Enduro

  1. I have one that has done 33000 and hasent been touched and I am going to give it some live and put a new piston in

  2. Just realized I have had my filter on backwards the last two oil changes I did I have a 1990 dr350s the pic shown above is the correct way though for sure? Small metal hole on outside and bigger uncovered hole towards bike?

  3. Thanks to this awesome page, I found my 1992 DR350S oil strainer for the first time in 21 years! I had previously always skipped that step during oil changes. It had about a dozen table-salt-sized black particles in it, and was 99+% clear and free-flowing. Removing the strainer damaged the old o-ring. Anyone else who hasn’t cleaned yours yet, maybe don’t bother. Ever. Then you don’t have to remove the skid plate, either.

  4. Nice job on the step by step oil change and level check. I have a 92 DR 350S with 13,200miles and she’s never skipped a beat. 🙂

  5. Hey thanks for these tutorials on the dr350! The detailed descriptions and photos make it easy to understand the process. Keep it up, you rock. Hope the leg is better.

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