Ask Dave: Motorcycle Fork Oil Level

We all know there's oil in them there forks. So... how much and why? Answer me that, Mr. Dave Moss. G'ahead, try.

[gsab]

One of the facts that makes this channel (Dave) so popular and liked is that I've never heard him saying what must be done and certain numbers need to be followed. He gives you the knowledge not the "copy paste" method and is up to you how much are you going to learn and apply in real life.

[ericsmith]

I love the great info you share in these short videos, much appreciated.

[hpac]

this was awesome, it takes the fear out of my questions. knowing I can play with oil levels and not being 100% dealer spec is great.

[hks]

I just changed my fork oil myself for the first time thanks for your videos.

I just got this bike recently and it has been so stiff despite I turn down the compression and preload.

I just poured out the old fork oil and it is about 120ml more than the manual recommended. That might explain why it was so stiff.

Can't wait to go for a ride tomorrow

[mickl]

Thanks for the advice in this video. I've just done a fork oil change on my 2003 Yamaha R6. What you say rings true to what I was feeling with this bike. They were 'overfilled' by 100ml in each leg. The bike wouldn't hold its line properly, was very nervous, turn in was slow and over bumps it was kicking back. The height was 70mm, Yamaha spec is 106mm. I've now set it back to original specification and it's like riding a different bike for the better. Holds it's line, turn in is spot on, loads more feel.

I can't wait to get this on track now and have a bit more of a play with the settings.

[rogereustace]

alot better coming from your mouth than reading from a book....keep it coming..Cheers.

[thesickening]

Love the vids Dave, keep 'em coming! And this one pertains to what I was experiencing just last week at the track, where our local tuner suggested I run slightly less oil in the forks. Now you just explained why. Thanks!

[symoonstar]

Thks Dave.this gave me choice& no hesitate to top up oil...

[cruisingthethaiway]

This and other videos are very helpful. Retired certified master auto tech in Thailand. 2019 Tracer 900 GT.
11 lbs Givi engine guard. I'm 183lbs. Performance upgrades. Run in A mode wot most of the time...
Stock suspension was a major disappointment.
Installed Ohlins ya-357 shock.
Huge improvement but at 15, 000km had front rebound at one click... To soft, floundering.
Stock oil is 5w.
Did dump and run with Repsol 10w.
Oil removed measured 50ml short of what service manual said.
Refilled to exactly what manual said knowing has some residential still in shock.
Did setup per previous videos...
Just did my favorite twisty road test ride. Wow, it finally performs the way a bike should. The bridge jumps that could only do in 2nd gear before was able to easily do 3rd gear. Big air and lands flat, smooth and stable.
Trailbreaking then power on at 8, 000 rpm snapping a power wheeie in 2nd gear... Most aggressive ride ever.
Thanks Dave

[donwolfjr]

I think you just answered my question of is it possible to just add oil to the top of my forks on my Gsxr 750 without removing them. Great video and info!!! Thanks Dave!!!

[kevinchamberlain]

Nice one! Nice and simple, use our brains and get it sorted! Thanks for this!

[dirtboyslong]

Great video! I recently changed my Honda CRF Showa fork oil with Yamaha S1 zero weight and made huge improvement to small bump chop.Just purchased RMZ with SSF air Tach forks, and they are harsh through mid stroke. Do you recommend lowering fork oil hight or swap to lighter oil to start? Thanks!

[bccapone]

great info thanks Dave, I've got a 2009 gen 2 hayabusa and the service manual that I found online that I believe is the gen 2 from the shape and model of bike on picture, it says 95mm air gap but everywhere else online people are saying 120mm and 110mm air gap, I always ride two's up and I've ordered seals and a 7.5w fork oil so what's the best height to go with as I'm really not sure what to do, stock oil is 5w but my preload was almost all taken up from watching cable tie, I'm doing just normal road riding so would it be a problem going for 110mm gap for a plusher ride rather than 95mm with a 7.5 w, thanks

[Jodyrides]

Dave. I bought a 2008 Yamaha royal star venture used a couple years ago. My owners manual suggests that the fork oil need never be replaced. The words they use are, not necessary.
these are air assisted forks. That means I am putting air in that has moisture in it. I cannot see that moisture ever escaping unless I have a bad fork seals that will also allow oil to escape…
I feel that Yamaha was not 100% correct in suggesting that the fork oil need never be replaced, simply because of the moisture in the air introduced to the forks that will cause corrosion of the fork springs, and their corrosion, no matter how tiny the particles will not do the insides of the forks much good.
I have owned dozens and dozens of motorcycles over the decades, trials, bikes, trail, bikes, motocross, road racing, sport, bikes, touring bikes, commuter bikes, I have always done my own work. I have never drained fork oil out of any of my forks that looked as fresh as new. It always looked cooked/ dark/ sometimes black

[pott]

wow someone who knows what he is talking about...thanks Dave.

[shankarsg]

What will happen?
Rider weight: 89kg
Pillion weight: 76kg

Fork oil used: Heavier oil than recommended.

Fork oil quantity: Quite less than recommended.

Will the ride be plush-comforting coz of lesser oil?
Or
Will the ride be stiff-coz of heavy oil?,

[restlesslifestyle]

Fantastic explanation Dave, thanks so much

[outbackenduro]

Hi Dave Moss respect to you and your years in this game. I have a question about when loading a dirt bike onto a trailer. 1) When you use straps to hold down to bike side to side strapping on the the handle bars people are telling my I need to use a wooden block or I will blow the fork seals. (these are an open chamber upside down fork KTM) I don't agree. Here is my logic. Once the bike is strapped down compressing the forks or really your compressing the springs only not the oil ... after you bleed down the air using the fork bleeders you cannot blow the seals as there is no pressure. Before you answer lets say during the traveling the bike does not oscillate up or down I believe that no pressure will build up in this case therefore no pressure on the seals. What do you think ? Thanks mate

[johnpublic]

Love your no bull shit suspension videos

[ColoradoS]

Thanks for the videos Dave. I replaced the oil on my Aprilia Shiver and went with a slightly thicker and slightly more oil. The Marzocchi forks that came on mine (Aprilia used Showa and Sachs as well) are non adjustable and had a bunch of dive under braking. I figured that this was my best course of action as no one makes a spring or cartridge kit for the OEM Marzocchi, although they do for the Sachs and Showa options. It helped a bit for sure but I can't help but dream about how it would be with a nice set of suspenders... Just another reason to consider a bike upgrade, based on one of your past videos it seems you may be a fan of spending the extra for the Multistrada with the Ohlins instead of the electronically adjustable Skyhook?