Ask Dave: Motorcycle Fork Oil Viscosity
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- เผยแพร่เมื่อ 18 มิ.ย. 2017
- www.DaveMossTuning.com
Choices choices choices. 5 weight, 7.5 weight, 10 weight. Some is blue, some red, some green. Sheesh. Fork oil needs to be changed every 5000 miles. You can visibly see the difference in fork movement between identical ZX6R's in this video. • 2 Clicks Out: Crushing... . One has 800 miles on it, the other 5000. How often do you change your engine oil?
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Yeah, my mechanic told me that I need thicker oil for my fork. I'm trying to lose weight but changing oil is faster.
LOL
True that - I know as losing 20+kg took more than a few weeks.
Lol..fuck yeat
haha yeah who needs to loose weight...
I need a t-shirt that says. "My doctor told me I need 20W Fork Oil"
Straight forward, and, superb simplicity in explanation in your education again... spoken truly. Thank you Mr, D Moss... blessing to you sir.
Great stuff Dave - the whole suspension thing is a fascinating subject! 👍🏻🛠
Another simple but helpful video Dave. It is even more helpful when your bike have no fork adjustments whatsoever. Just like my Yamaha XJ6 (FZ6R). As I am just a slightly heavy and riding a bit too aggressive on weekends I opted to go from standard 10W to 15W. So far so goog.
Really useful video, I'm about to change the fork oil on my old Ducati 851 fitted with Showa GD11 forks, looks like I need to find an equivalent to SS8 Fork Oil
Thank you for the life of Brian reference. +2 cool guy points!
totally agree change your oil! when i got my 2002 cb900f hornet it was super comfortable just floated along extent to get used to the move from 2000 wr400f to 2002 cb900f it let me concentrate on looking and pointing the bike where i wanted it to go and also to install trust that the bike can and will sort itself out not if but when its slippery or bumpy being soft got rid of the "pucker" factor that instinct to shit your self when something unexpected happens
about 2 weeks ago the seals leaked on one side so i orded the seals bushes and oil pulled them full brake down clean dry fill per book cycle check lvls back in bike the diffrence in the feel and feed back wow huge not sure what oil or how long it was in there for but wow so much more crisp and turnable its like the shock had been changed or re worked who knows but now that im really starting to ride the bike a good bit faster in the bends to load the suspension and lunch out of the bends its just addictive getting the power on as it opens up and the bike digs down pushed out a little and rips out of the bend
i really really want to go do some ride days but the cost! here in Brisbane aus its like 300 bucks a day plus gear as i dont have track gear just a summer jacket and gloves yeah i know but gear is cheeper and easyer than skin grafts but dam why do they make it so expensive to go ride in a much safer place than the streets? it should be like 30-50 bucks to go ride maby more people would go rip around the track rather than on the streets doing dumb stuff
This is gold content now i know i can change the viscosity of my fork damper behaviour.
Thanks Dave - many a question answered! 👍🏻
Thank you for the video, it was just what I needed!
Hi. My motorcycle uses semi 10w40 oil. I have in a quart a mix of liqui moly, Motul and Wolf Belgium semi synthetic on excedent from previous bottles when changing oil. Can I use this tree brand mix with identical API and JASO specs? Thanks in advance..
Did that on my CB500Four K1 40 years ago :-)
Got a set of Girling gas shocks for the rear so somthing had to be done with the fork ;-D
Used 3 liters of fork oil (3 diff. viscosities), two sets of preload bushings and a month of experimenting - ended up with a "killer-suspension".
Gave my confidence a "god-like"-no-corner-is-too-tight-and-breaking-will-be-too-late-boost - But got many 750+cc riders into severe troubles trying to keep up with that little "CB5" ;-D
Used one step heavyer oil, a little extra preload and that much extra oil that it just stayed on a 5mm compressed air cushion and didn't bottom out on "solid" oil :o)
Wow - great stroll down memory lane :). I did the same fork experiments on my RD400, 400/4 Supersport and Suuzki 500 Titan. So much easier back then......
I like the way this dude talks
30 belray babe!!!
2005 Softail Harley-Davidson put it in you don't need Progressive Springs the 30 weight,holds it nice and tight around the corners
It's the 5wt Racetech ultra slick. Wish I was in CA, sadly I'm stuck in Ohio. Riding the 555 Triple Nickel today though, which is a hoot. Thanks for the reply Dave. I'll try out the 7.5wt and see how it fairs.
Use the same volume/oil height.
thank you so much sir , now I'm putting liqui Moly 15w fork oil in my pulsar ns200.
I'm 5.9" 67 kgs, but I'm a aggressive driver so OEM fork oil don't help me..that's the main reason I want to replace my bike fork oil.
Again thnq so much sir ...
Love from Delhi, India 🙏
Had to buy fork oil because of a massive leak out. I went for the "same weight" but with a known brand, for street and off-road, one, i actually go on some light off-road..
What an improvement!
So, it might be a good idea to try a good/another oil first, before changing the weight.
Great work an thought process to arrive at an excellent outcome.
Dave, if the suspension was dialed on old fork oil you have to make adjustments to the rebound when you replace the oil (using the same viscosity) You should open the rebound or close the rebound (1/4 to 3/4 of a turn as you mentioned in your rebound video) ?
No hats on backwards, no silly music......this man is to be trusted.
Dave thank you very much. Today I managed to change fork oil to my marzocchi rac 50.was very easy but took me almost a day. The cap opened very easy with a pin spanner tool and I managed to drain 625 ml of old oil from total 655ml (according to manual). Not bad I think. I exercised the forks couple of times (6 or 7)thr last 200ml came out really hard. But was very interesting that the forks without oil work like a normal spring.oil makes hudge difference! I used 5w as you suggested to me to some other video, though I didn't ride it yet, cause I need to make some more things, but it works really really smooth and it changed sound, it sounds Ike pressured air. Pretty cool. By the way I changed oil too, to my ohlins steering damper and now it's awesome! Thanks once more for these amazing guides. You re cool Dave!
Thanks for getting your sleeves rolled up and making a difference. Awesome stuff! Congrats :)
@@CatalystReactionSBW
😊😊😊 The most amazing stuff is that through the process , you get deeper understanding of what oil does to the suspension. Behavior with or without oil is dramatically different. 😊Even more I feel it as I work the steering damper in my hands. the old oil seemed that lost properties, (became like water)with a dead spot in the midle and now with the new oil (I put 5w the same as forks) it feels more like a hydravlic suspension. smooth solid and progressive move.
So I guess that same principles apply to forks also. Old oil looses properties through time and stress. I'm very curious to se how rebound and compression affected after the new oil and from 7.5 stock to 5w. I guess I need to put some more clicks, but I will really ride it with the old setup, to notice what has changed.
Keep up the good work.👍Greetings from Greece
@@CatalystReactionSBW well, I owe you a big thank you dave. My bike feels like she steps on a carpet. I feel the front end so smooth!! So precise. I have half a litre left, so I will buy one more litre, I will let it work a couple of months and then flush it again with new oil! Shame I can't service the rear shock too 😂😂😂😂
@@vr___46excellent and thank you for the feedback - hopefully others benefit from your experience and get their fork oil changed!
Actually, that’s a very good analogy, Dave. This is why I like your videos.Practical and a little reasonable info. My dumbass dealer don’t know the difference between 2,5 and 15w oil
Dave, I did just what you mentioned. When changing fork oil on forks I was rebuilding, the manufacturer spec was 10W but when I looked at the viscosity chart as tested I went with a Silcoline Pro RSF 7.5 (I think) to get a 10 W. The bottom line was...after researching the weights as actually tested, the claimed weight on the bottle has almost nothing to do with its actual weight. Was I right?
Yes, your research validates the lack of standardization in the fork oil arena from marketing to testing.
Nice advice. Thanks Dave.
Your the man Dave!
well,i did not knew that my actual weight was important in the choice of the fork oil thickness,,its very interesting.185 pounds and 5 feet 8 ,,an old man of 64 with a stock Bandit 400,1991.i am working on a winter project here in Quebec .After the front fork i must found an alternative for my rear suspension,,it is so hard.But i will dismantle and grease ALL the rear pivot ,,bushings,,bearings i will found because i see no grease zott anywhere.Thanks for your Instructive video.Merci .Gervais de Riviere-Bleue au Quebec
Bonjour Gervais. Enjoy the Winter rebuild and hopefully you get a solution for the rigid rear shock via maintenance!
I LOVE that you quoted my favorite Monty Python movie, so very underrated lol.
I have a technical question that I can't find a definitive answer to: If high shaft velocities are causing spiking events, does a thinner oil with less damping port orifice area move the spiking event to a higher shaft velocity, if the damping at lower velocities matches thicker oil with greater port orifice area? ie is thinner oil with slower damping settings better than thicker oil with faster?
Dude, dont ask him a tech question like that, dont you know he is the David Brent of the suspension World 🤣
Good advice thanks.
10 s1000rr , 185 lbs rider. Manual says sae 7.5. Recommend plz? (Maxima fluid ideally)
With the recommended 5 weight the bike was comfortable but dived too easily when the front brake was pulled on. Going to 7.5 weight makes the ride it a bit harsher on bumps, but has reduced dive substantially, which allows me to ride more aggressively which means fun time.
Have you thought about/did you try more oil volume with the 5w to leverage the air spring effect?
Many thanks for your reply and uploading these informative videos. ::: I did think about more oil, but I was concerned about having too much pressure with nowhere to go but the fork seals. The higher weight fork oil resolved the diving issue which was something that was spoiling how I felt about riding the bike overall. The slightly harsher ride is only really noticeable roads that get little maintenance and I can compensate for that by kerbing my enthusiasm there. I did watch your video on fork springs today too and I'll try your zip tie trick to see what kind of travel I'm getting on the front end under different riding conditions. I am thinking of trying progressive springs to see if it will give me the best of both worlds.
That makes sense, so once you see how much travel you use, think about a fork geometry change, then test again.
The David Attenborough of moto maintenance....more please
Hey Dave what is your preferred brand of fork oil?
Or do you stick with manufacturers recommendation on brand for fork oil.?
Ok Dave, you're still getting views. The service manual for my 2018 Suzuki GSX-R750 calls for SS-47 10W fork oil and my local dealerships only have BelRay 10W fork oil (Viscosity Index 118), so I ordered 2L of the Maxima 10W (Viscosity Index 182) because theoretically the 182 V.I. will have better stability throughout the cool to hot temp range of the day. And...I'm a lighter weight rider at 150lbs with gear that mostly rides in warmer Southern US temps, so I did not opt for a 7.0-7.5W fork oil (yet) future testing TBD. Also, thanks to your BPF vid which I view via my subscription to the Dave Moss Tuning website, I have found BPF fork servicing to be a relatively simple DIY function and will be performing my own fork services myself. All this to say that you have been VERY helpful and I am very glad I paid the $49.95 annual subscription fee for your site. I highly recommend others do so also!
Thank you very much for your informative post to help others understand the need to study V.I. and use that information wisely. I also appreciate your support of my website and thanks for the recommendation regarding the value of the content.
I tried going from 5 to 10 weight...huge difference and was quite harsh. Went back.
What’s your weight?
I wish I had an app that would have this guy read my email. I can just imagine what that spam from Domino's Pizza would sound like!
switching from weak /soft/stock gl1800 fork springs to progressive springs..
Since the new springs are going to rebound faster than the old stock springs..Do I stay with the recommended weight fork oil..
I am pretty sure my 2002 Goldwing has cartridge forks. Is the fork oil used to control/ damp the spring rebound as well as a lube ,Or just as a lubricant?
also:
i dont think so, BUT- is thicker fork oil more or less likely to blow fork seals??
also:
when refilling the fork tubes with fork oil, should I have the tube slightly inserted into the lower fork leg when reinstalling the cap/ top??The point is, so that I can Displace a bit of the air space in the tube,So that I won’t have trapped air pressure in the fork tubes..
I remember when they used to use air in suspensions, which I am pretty sure was the worst type of suspension spring you can use because of the rising rate .. I remember motocross bikes had a Schrader valve at the tops of the fork tubes in the 90s, that was to let air pressure out of the fork tubes that built up while riding in the tubes..
Does this make sense to push the fork tube in slightly to account for sag to displace some air space before installing the cap?
15w Bel Ray is a common change, same oil volume as the manual requires. Fork oil is damping in these forks.Thicker oil will not blow out seals, too much oil will. Tube fully bottomed out in the leg if setting oil level manually, pull the tube up and down several times to remove air. Wait 5 minutes then measure oil level.
I'm running a wr250f and works well. I run it at the track sometimes but after I blead the forks the air came out and now they bottom out some times it calls for number 5 .. how high can I go to help out but not make them to stiff for offroad
The compressed air became an air spring: th-cam.com/video/EiZY0lcqeR8/w-d-xo.html Over time, the forks will collect more air, or you increase the oil level slightly tomake sure you have a smaller air chamber. So, you can add 50ml to each fork and see if that helps with bottoming.
Out of sheer curiosity...
As you stated elsewhere, racing forks typically use 5 wt.
Is there any advantage to using a 5 over, say a 10, with correspondingly larger orifices and softer shim stack?
With larger orifice and softer shim stack, 5w over 10w would be good where roads are very irregular, bumpy and ambient temps are normally 10-20C on average
Great video! I am going to be changing my fork oil soon and this video had me thinking. I looked up a chart and there was two different Viscosity Indexes (VI). There was "Reported VI" and "Recalculated VI". What mean what and which should I be looking at? Thanks so much in advance!
Reported is what is on the label or in technical documents from the company. Recalculated is 3rd party review and their VI numbers. If you trust the source of data for recalculated numbers, use those.
@@CatalystReactionSBW thank you very much!
You heard it here folks. Change your Forken Oil !!
Can someone tell me what happens if you put chain oil in your forks
I'm waiting for the replies too. Are you talking Scott Oiler fluid? That is fairly thin as is has to flow somewhat evenly (I've had two bikes with that on now). We did try 5w fork oil but it would not flow correctly. Perhaps your answer lies in the reverse process we did?
viscosity is helpful unless you have a Hardley Davidson. type B? its 5-20wt depending on the harley group. i have 10 and have dented the fender bottoming out. yeah the bike is 34 years old. going with new springs and maybe go back to 15 vs 10wt. may go 20. thanks for the info.
Also think about increasing oil volume to leverage the air spring effect th-cam.com/video/EiZY0lcqeR8/w-d-xo.html
I just love your videos and I've learned so much! Thank you!
Small Q.: Would mostly "2 up", combined weight of 150kg, riding only during summer, be a sufficient reason to go from 10 to 15?
My bike has had lame suspension from stock, but I've upgraded the factory monoshock to Welbers 640, and front fork springs to progressive, but kept oil viscosity of 10 as per manual .. handling has massively improved, but I can still see some room for improvments .. so 10 to 15? 🙂
Yes, 10-15w would make sense. Have you altered the oil level at all? If you ride mostly 2 up, more oil would be very helpful to leverage the air spring effect and provide a lot more braking stability. ttps://th-cam.com/video/EiZY0lcqeR8/w-d-xo.html
@@CatalystReactionSBW Thank you kindly for answering, much appreciated!
When I rebuilt the forks with those progressive springs I mentioned, I refilled the oil according to what was specified in the Hayens manual: Viscosity 10w, Capacity 499cc, Height 108mm ... I'll try adding a bit more oil as you advised, to bring the height up to maybe 90esh mm, and see what that does, as I'm not too keen on re-valving the forks on this ancient oil cooled bike of mine, with over 92k km on the clock. 🙂
@@ghassanalfarra8935 Before you install the forks back on the bike with an oil level at 90mm, see f you can reach bottom out by compressing the forks by hand. If you can, the jump to 15w would be required at an oil height of 100mm.
Ohlin Fork Oil for Ohlin Cartiges only has a part Number.. I found a spec chart it basically is 5W .. Ohlin Fork Oil $28 per Liter Bel Ray Fork oil $16 per Liter..
Hi i have yz250f 2008!
I am 88 kg
I want replace the old fork oil!
I need buy the kayaba 01 fork oil or I can buy another cheaper? What you suggest me w?
Im about to change the oil of my monster 821. The fork feels too soft specially during breaking (i enter the track casually). I thought of changing the forks to andreani adjustable springs but i might just change the oil from 7.5 to 10, save some momey and try to buy a track bike soon haha. Awesome videos Dave. On point.
As well as try a more viscous oil, make sure you get the volume correct to leverage the air spring effect: th-cam.com/video/EiZY0lcqeR8/w-d-xo.html
@@CatalystReactionSBW thankk you so much. Ive been learning all this after going to the track. Does this mean i need to check oil level and perhaps leave more empty gap since viscosity is higher?
@@santiagosalcedo7909 In principle yes - BUT - you will in time find your own oil level to really effectively use the oil level for air spring effect.
@@CatalystReactionSBW awesemoe. I will try to check it before putting them on. I wish you were in Spain to have a proper lesson haha. Cheers
I have a 2006 zx10r and when I ride I can feel every little bump in the road and the forks seem fine no.leaks could the oil need to be changed
How much fork travel are you using via the cable tie? How much shock travel are you using? Is your preload all the way in along with compression for the forks and shock? Do you know where your settings are? We need these data points to find out why verses guessing. davemosstuning.com/?s=clicks+turns+faces
I have a feeling that my 2012 ER6n forks are too harsh/stiff when I ride on uneven road. Too bumpy.
On manual, forks use 10w kyb g10 and I've not yet change it now at 20.000+ kms Lol... I know it's time for oil change.
So, before I change my fork oil...
My question is: What is your recommendation for oil viscosity to make my bike more rideable/comfort? Should I change to thinner (like 5w) or stick to factory spec (10w), or change to thicker (15w)? I am 80-82 kgs man (is it heavier or lighter side?)
Thanks!
Check your static sag first. I think the bike is tuned for heavier passengers and you probably will need to cut the spacer in the fork down. Take a look at the fz07 video from dave
@@andooy Ok.. I'll search the vdo about fz07 that you've mentioned.
Love that movie. Perfect reference
Okay so i'm gonna send my bike over to the US for the annual service.. Worth the cost of shipping for Dave's brain
Thank you sir
Back in the 60s here in the UK there was really only one fork oil Castrolite 30 mineral oil , a straight grade mineral oil that was an upgrade for most forks and sits around Bel Rays 30 Fork Oil as far as viscosity at temps ( Cs ) is concerned .The forks characteristics was then modified by the quantity and compressibility of the remaining air gap . All done with adjusters now . Isn't modern shit wonderful ?
Dave's not the Messiah, he's just a very naughty naughty boy. Lol!
Suspension guru your never too old to learn something new as much as U know stuff someone's know d more like Dave Moss 🏍️
I learn every day as new bikes are coming out all the time and then they are modified which changes everything. A day without learning is a day wasted.
Dave interesting video thanks for posting . I have ohlins forks on rsv1000r. The forks bottom out even when I turn on the preload. Would putting a 2.5 weight go some way towards combatting this problem without new internals.? Also will it cause me problems when powering out the bends?
Thanks in advance.
2.5w will make the forks move faster through the stroke. If that is what you are asking, yes. I think you are asking about fork air spring and oil volume: th-cam.com/video/EiZY0lcqeR8/w-d-xo.html
A Dave Moss app huh? That's awesome
It's been out there for a few years now with section on street, track, race and tires that contain text, podcast and video content to cover all learning bases. There is a free section for you to browse as well.
Here's my new TH-cam subscription channel with all the premium content for one annual or monthly price th-cam.com/channels/uoZgTsCBGCjSHwho37er9w.html
I have a 2004 Kona Caldera. My question is what kind of suspension oil do I need? I'm currently getting my bike powder coated and had to take everything apart so my front marzocchi bomber shocks are completely taken apart and drained. My local bike store said I needed a specific oil but wouldnt tell me what kind and to find out myself. And what kind of grease also?
As that is a Mountain bike, Marzocchi research shows a 5w or 7.5w for the forks depending on weight and use. Cannot find the specific volume by cc's but the shop should know.
Hello sir , I do not own any heavy and expensive bike but I have been riding honda XR 150 l for a year and having a telescopic fork front suspension , the garage person said its oil needs to be changed and I have no idea which oil to use on my bike , thank u.
Depending on your weight and type of use, 10 or 15w fork oil to the volume specified in the service manual.
Hii Dave am having some questions for you that may help me aloot: 1st ,fork oil is atf fluid???I know atfs have kinda inner types mercon II ,mercon 3 ,mercon v ,type F ,also there are steering fluids and such , why this question?? Well I noted some fork oils are red,green,sometimes even blue (I love this one) and also amber and clear colors but ofc color doesn't mean anything than the viscosity at 40 and 100c so thing is....can I use this atf oil in my suspension???will it destroy the seals or the stanchions coat?? Cuz if they're in the viscosity range in my fork manual they're supposed to fit good right?? U may wondering why would I change fork oil with atf, well in my country a bell ray fork oil being imported would cost like 100$ plus taxes but atf would cost 4-5$ in prolly valvoline ,Amalie,castrol,amsoil etc brand and also some steering fluid brands too for 2$ ish so since u are the oil guru I thought in asking u cuz like motorbike forks I wanna use it in hydraulic mountain bike forks cuz mtb lubes comes in even small packages with the double the price even in USA so in order to protect my forks I got immersed in all this oil quest cuz since now I used motor oil for the stanchions but I didn't touched the cartridge yet but hey there are some atfs that would match the viscosity fairly close to sae 5w-10w just a lil bit up or down for a few cst's I hope u can help me Dave good wishes 😁
Fork oil comes in many different viscosities specifically for forks. ATF can be used but only in certain applications, normally old school damping rod forks where that viscosity is appropriate. Colors have nothing to do with viscosity per se. Some colors are brand identifiers (red for Honda oil). Any fork oil will work, just research the VI of the recommended oil so you can find something similar. CsT is good information for track and racing.
ohh new info for research :B thanks Dave ill check the VI then ,great info btw i knew u would help me ;)
What would you suggest for a guy that's huge like myself for fork oil weight.. 6'2 305 street and mountain riding on a zx14... Love all your videos useful info.
5w is stock to I would go to 10w but set the oil height to 110mm. If you bottom out via the cable tie placement post ride, 1.1kg fork springs needed.
a mechanic told me a thicker oil could damage the pass of oil in the valves. that's true?
dave..
among other machines. i also ride a 2008 yamaha royal star venture..30k miles on it when i bought it in october 2021..my 3rd venture since 1986..
there is not much of a selection of fork springs and no selection of shock spring upgrades.. I upgraded the springs on my 86 venture and it transformed that machine into a much better handling machine that I did not need to use air in the suspension after the upgrade..
my 2008 venture only has air pressure adjustability… no spring preload or damping settings to juggle.
So:
The forks max pressure is seven psi
The shock max pressure is something like 40 psi
I realize that air is the least desirable type of spring to have in a motorcycle suspension.. practically Stone Age..
so:- even if I could buy upgrade fork springs..would it be just as effective to simply stick with air pressure instead of changing fork springs, Since i cant upgrade the shock spring to have balance front to rear??
I do not carry a passenger. This is a rolling lazy boy..no hurry..I do not sprain the speed limit even on the Interstate roads..But I am used to better suspension on my sport bikes, I just had a GL1800 Goldwing , I upgraded the fork springs and the shock spring to Progressive brand when I change the fork seals and bushings and fork oil.. I bought the gold wing which was a 2002 in 2018 with i’m only 13,000 miles on it from the original owner. It still had the original tires on it. The suspension was shot because I believe it sat on the side stand it’s whole life and the springs were just tired, they felt limp, and that machine did not have air suspension..
so do you think it’s a waste of time to install aftermarket fork springs, I think there’s one company, traction dynamics that offers a set of fork springs for my royal star venture, but I’m still stuck with a standard shock and no option to change the rear spring.??
Can you advise me on the weight fork oil I should use? Possibly the height from the top of the compressed fork with a cap off? Without the spring in it?
Fork oil would be 20w to the stock volume or 150mm oil height. For the shock, Canon Racecraft can make you a spring should you feel the investment to be worth it: www.cannonracecraft.com/
I have found forks to get very dirty over time. I am always surprised what I clean out come rebuild time
Hi Dave, I’m new to your channel. Can’t get enough of it. Quick question, my 09 Daytona 675 (NOT the R model with Ohlins) has had the cartridges changed to KTech’s by the previous owner. Should I use the manufacturers recommend oil or contact KTech to see what they recommend?
Btw I’m 75kg and the bike is mainly used for track days.
Thanks in advance 👍🏼
Use Motul 5w, oil height at 120mm
@@CatalystReactionSBW I have a 2015 FZ-07. When you measure oil amount in forks, how do you measure that? From the bottom to the top of the oil level with a dip stick? I saw in a video a guy was measuring with a syringe pump, measuring down from the top.
@@jacksonwholeexperience409 Spring and spacer out, outer tube fully bottomed out. Measure from the top down: th-cam.com/video/k4BxjmIwVdY/w-d-xo.html
Does leaving a smaller air gap or more oil equates to same result such as higher viscosity?
The oil level is to set the air spring effect and compress air to help with bottoming issues. Thicker oil flows slower so in theory you should get to bottom out slower with identical settings.
saludos, tengo una moto vzr 1800 o m109r y no consigo el fork oil recomendado por la marca en el manual (L01) DE LA MARCA SUZUKI.Que otro puedo poner. gracia
Maxima or Motul 15w fork oil
I can drain my engine oil via a drain plug. My MC forks don't have one, so it is not likely it is going to get changed unless it starts to leak.
Yeah that's fine if you are just chilling kn the road but chasing time on the track it makes a huge difference
Wish it were easier on the Duc Enduro 1200 to service it myself.
I've heard that viscosity breakdown is due to heat and that fork oil doesn't experience this breakdown as it's the only oil on your bike that doesn't get hot enough to. Further the only reason why fork oil needs to be changed is because of particulate buildup from the spring compression causing lots of little particles of metal. Meaning as long as you filter your fork oil every 5k miles you can reuse it as there is no viscosity breakdown. It that not true?
Viscosity breakdown is due to 1. Heat 2. Shear forces. 3. Oxidation/chemical breakdown/additive depletion. The short answer would be "no" but that doesn't help, so here's an article that I reference when people ask this question. It is science based but easy to follow: www.machinerylubrication.com/Read/475/oil-breakdown
@@CatalystReactionSBW Awesome, thanks for the reply!
Sir David. Currently i have a yamaha nmax 155 scooter. I used motorex 10w-30 fork oil for my front fork. I like it.
What can you say about the fork oil i used?
I refilled it with standard service manual recommended fork oil volume.
Great to see someone getting work done! The oil you used will offer good movement for the majority of road surfaces. Going with the stock volume makes sense to start.
@@CatalystReactionSBW thanks sir for sharing such great contents. I learned alot from you. A very useful knowledge in my line of work as a service advisor for Yamaha big and small bikes.
Dave. Thanks a lot for the videos! I have a Yamaha Vmax second generation. The manufacturer recommends a Yamalube M1 that 0WT. In my country isn’t available. What caí I use?
In colder climates, Motul or Maxima 5w, in warmer climates Motul or Maxima 10w
Dave Moss Tuning I put 3,5 w but the forks are to hard. And are bouncing back útil you hear a metal sound. I put the recommended amount that the manual says. Help me please
@@papirri12 That sounds like (from your description) that the cartridges are not bled correctly so you have air in the hydraulics. Did you bleed them before assembly?
Anyone been running motorcycle 5WT fork oil on MTB? Fox is recomending teflon infused 5WT, but similar motorcycle 5WT fork oil is 1/3 the cost.
Hello Dave, I'm about to change Fork seals and dust seals - i'm kind of trying to figure out what oil to use, Bike is CBR600RR year 2006, in service manual I found that they recommend Pro Honda supension fluid ss-8 (google it a bit, it should be 10w, as Motul recommends too).
Fully equipped i have around 77-78kg, and I was thiking about putting in Silkolene PRO rsf 5w(viscosity index 372) which is semi synth by their specs. Or maybe try to go Motul Factory Line light/medium(viscosity index 131) 100% Synth?
Thank you for your help! :)
I would go with Motul Factory Line given your light weight.
Dave Moss Tuning thank you very much for your advice. I will try with that and see how it goes.
hey Dave, I bought a 10N/mm (1kg/mm) linear springs for my CBR1100XX, weighing 100kg in gear, I'm wondering which oil should I use? The manual recommends Honda SS8 which is a 36 centistokes oil, should I stay within these specs or go lighter? Also, the fork spring manual advises 140mm air gap, Honda says 142, I presume both gaps would work but there's no mention is the air gap measured with or without springs inside? Thanks a lot
Spring out is standard procedure for air gap. I would use a 42 to 44cSt oil for those forks.
Hey Dave! I've changed my fork fluid to 5W, instead of the oem 7.5W, on my 2007 R6. Considering this is a 1/3 reduction in the oil weight, do I account for this in the manuals baseline settings by subtracting 1/3 of the suggested clicks and working from there?
If using 5w, you will start at 30-35 clicks in out of the stock 50 count.
@@CatalystReactionSBWOh ok. So the same as if it was the oem 7.5. Cool. Thank you!
im a big guy and switched to 20 weight on my 87 concours and it felt way better. previous stock weight it felt was kissing the pavement in front everytime I was braking... lol
Thanks for taking the leap and finding what works best for you and your Concours! A tip of the hat to you :)
Hi can you tell me what oil fork to use on a honda varadero xl 1000 2008 , i have 120kg and the last tine i go white 10w but is not so good for me :( thx
15 or 20w Maxima or Motul to 120mm oil level.
Flipping the bike upside down to fill the fork drain plug is hard
6k miles? Oh crap! Mine was factory filled 23k miles ago. Race tech compresser and level.gauge STAT.
Say goodbye to the lava lamp oil :)
Hi dave, hope you are well, for my yamaha fjr 1300 mod 07 wich is the viscosity in front suspension you recomend dave, 10 or 15? thanks
For the 07 I believe we used 20w and 500cc per leg.
Excuse me what's the difference between fork oil 10W and engine oil 10W - 40.
Thanks too much
Engine oil is designed for cold starts and high heat and durability among many moving parts hence the 10w50 etc, verses fork or shock oil that is designed to work under a lot less heat and stress so we have a single weight. ATF is a good example of a cross over oil between forks and engine for older motorcycles with damping rod forks. Newer cartrdige forks require more specific weight oil based on piston and valving deisgns.
Hello DM,
I own an old motorcycle ( 1982 Kawasaki KZ440 C ), in the service manual it is mentioned that its forks oil specs as ( SAE 5w 20 ) which forks oil does it match? Is 15w good for it?
Today, 15w (less than 70kg) or 20w Maxima would work based on your bodyweight.
Hello Dave, in a slipt function fork where left leg handles compression and right rebound does the oil viscosity need to be the same or 2 different viscosity can be used. I require more travel on compression side and rebound is okay. I use a ktm duke 390 2017 and i weigh 55kg
I use two different oils in my MV 800F3 and you can change the volume of the compression leg
@@CatalystReactionSBW Thank you. it's inexpensive and more fun doing these small changes than change than directly changing cartridges
@@rautikd My MV Augusta F3 800 has 20w in the compression leg and 5w in the rebound leg. That works realy well for me at 85kg
Quick question, I put harder density, manual says 10, I'm sure D9, but I've put 15 in, changed oil seals, dust seals!!!, it's kind of leaking, residue on forks... i used red stuff came with seals, put that on inside and out....Is it leaking because of stronger oil!?....if answer is no, then will try and clean them on bike, if failing that!!!... Might be a bad set from eBay (shock - horror) but all did have a tight fit....manual says 441....I put in around 450 each leg, surely this wouldn't be the problem.... let us know if U can, will try tomorrow... I know I have the screw setting on top, I wonder if I loosen...hmmmm 🤔, only 1 way to find out.... ✌ & 💖
🌍 we 🙏
That volume change will not cause the problem not will the viscosity change. Drop the dust seals down, clean them completely. Wipe the fork tubes clean. Hold the brake on and push the forks 3-4 times, check for oil. Wipe off. repeat 6-8 times, If the oil reduces each time, too much grease on the seals.
As your the main man in the no . Can u tell me wot the fork oil .air gap is for a Honda CBF 250 I can't find it .any were. please
Research online gives 120mm as the oil height, fork tube bottomed out and no spring/spacer inside.
It's Viscosity Improvers what's breaks down in engine oil. But you don't have VI's in fork oil. So fork oil does not break down, does it? Or maybe not as fast as engine oil. On that basis 6k fork oil change interval sounds too frequent to me..
You bring up a good point of me sending a 6K sample of fork oil to a lab that could test it and provide an analysis of the oil compared to a new sample that was also supplied. I wonder where I could find a lab that could do this work. On the subjective side, I personally feel a substantial difference at 6k between cold and hot oil when riding verses new oil in the same heat ranges, hence the suggestion.
Dave Moss Tuning Thanks Dave, I am not that good at feeling the difference yet, so I will go with your recommendation.
Great website for some very good information on oils so you get a solid grounding in the important details. Very few people want to go this deep into oil though.
@dave moss tuning. i ended up purchasing maxima racing line 125 150 7wt. is this an acceptable oil? its petroleum i believe and the standard stuff is mineral?a local susp tuner said he uses maxima n said for me 7 is best
Yes, that will work great!
perfect thx you for youre patience w me haha
Nice 1 Dave👏👍Just a quick question I’ve just purchased a 50 year old Fantic Caballero TX 96😉and on the Instructions on the little Tank Bag it recommends FIna Solna 32 and obviously this is long gone😱 So I was looking at some of the Viscosity Charts and I think 10wt is the nearest equivalent for this, but I’m not a Lightweight Person Lol and was wondering if a 15wt would be better for me and Living in the UK 🇬🇧 it doesn’t get that warm well apart from a couple of weeks that is👍
Hi Rodney - brilliant acquisition!!! Try 15w and 25ml less than the service manual requires. Then assess travel used.
@@CatalystReactionSBW Thank You Dave I will do what you suggested😜 I have to apply for a V5 in my name to get a Registration Plate(Number Plate) and then I can get the Fantic TX 96 on the Road and start enjoying the open roads again 🤛🏻💨😃Take Care and Stay Safe Dave 🤞👍
Can you mix a 20wt and a 5wt 50/50 and get something like 12.5wt ?
You need 60% of 10w and 40% 15w for a 12w
I have passed 100 000kms not long ago on my bike. The front feels softer than it used to, probably it is time to change fork oil
Please also change all fork bushings as well
Yeah and it’s probably gotten thinner, too, the oil, not you. You probably got fatter, too!!🤣
I have had my 2017 honda fireblade lowered 20mm forks & wishbone, I'm 1.58m tall weigh 60kg. Is a higher viscosity fork oil recommended to avoid bottom out ? Service manual stipulates 5w. Thank you Jane
Hi Jane. 600 or 1,000cc? Lower a bike requires the suspension to be slightly stiffer with preload and compression. For the forks 5w is in both engine variants and oil level stock is high to use the air spring effect. You can go to 7.5w to slow oil movement.
RIGHT!
hey dave I ride a 2011 r6 I am 225lbs strictly track day and club racer am looking to change the fork springs and oil what do you recommend
1.1 fork and shock spring. 7w fork oil.
@@CatalystReactionSBW thanks very much
Hi Dave, Thanks for the valuable information. I am about to change the fork oil in my ZX14r and I weigh 77 kg (169 pounds) and am about 170cm tall.
I'm leaning towards Motul Factory Line Light 5w, which according to their blend chart (Viscosity @40 Deg. C)/mm less than or equal to/seconds: 18.0.
It has factory Kawasaki KHL-15-10 oil in it, which on the blend chart (Viscosity @40 Deg. C)/ mm less than or equal to/seconds: 15.3
Would this be the closest to factory?
Your help and advise would be awesome! Thanks.
Motul Factory light would be the better choice given your weight for better suspension movement. You need to balance that with ambient average temps to see if a slightly different cSt would be more appropriate (ie hotter climates).
Thanks Dave. Did you mean the Motul Factory light 2.5 or 5w? I live in Perth Western Australia.
@@G3516dude apologies 5w. Hope to meet you as my annual Australia tour includes Perth as a stop for classes and track day tuning.
Yeah, I’d like to meet you too and participate in the tuning session/track day, obviously when things get better and travel starts up again 👍🏻
what are the best brand fork oil manufacturers? or isn't that important?
We have found that Motul and Maxima offer great durability as does Motorex.
thanks for reply!
I keep having problems with leaking fork seals, I've changed mine 2 times in the last 4 years and their leaking again. I've tried cleaning them and they stop for a little while, but start back. My Honda 1300vtx calls for 10w oil, I'm thinking of going with a thicker oil to see if that helps. Do you think that it might? And if yes what weight would you suggest?
Two years is not an unreasonable amount of time for the seals to work. Are you using OEM seals or off brand? If off brand, the spring inside the back of the seal is often too soft and weakens over time. It has male/female ends and screws into itself. If you shorten the female end 3mm, the spring has a tighter grip around the seal and is less prone to leaking. Thicker oil would be helpful to damping but would not help with the leak. You can also have the chrome tube checked with a dial indicator to make sure they are still round.
Thanks, yes I'm using OEM parts. I've rode bike's all my life, I've owned 17 and I've only ever replaced fork seals on one other bike.
Then please check fork bushings for wear. That might be the cause.
th-cam.com/video/AxtIsyiZuK8/w-d-xo.html
Thank you sir. I ordered all new parts, except the tubes, and I'm going to rebuild them.
Hi can you tell me how increasing viscosity affect braking?
Thicker oil flows slower therefore fork compresses slower when braking to add stability.
A world famous track training school instructor once recommended us to use thinner fork oil rather than thicker. If I remember correctly; his reasoning was that thinner oil would permit "faster" (and/or finer adjustments) functioning of the valves and suspension mechanism, therefore it'd provide better surface tracking&traction. (Therefore also: viceversa) I would like to hear your view on this subject. Thanks for your diligent work. I have your DMT app. Although I'd prefer a simpler scheme to pay, I am a satisfied subscriber ; )
Using thinner oil will allow the movement of the forks to accelerate when dealing with bumps. That acceleration will provide greater feedback through the bars. It should in theory depending on settings allow the tire to return to the ground faster over larger bumps as well. All of this depends on the internal engineering that is present. Race forks use only 5w for that purpose hence the revalve expense, engineered products available and light oil being used. As for control of the oil via the compression adjuster, most OEM needles are changed to high performance needles supplied by after market companies to match the piston and valving kits they produce.
Thanks a lot! Best regards.
Thinner oil allows the fork to rebound faster to keep the tire on the ground. Changing your rebound settings can do the same. Thinner oil needs to be replaced more often and at the World level, that is not an issue on a daily basis. For us track and road riders that is a $$ concern and using thicker oil will give us greater longevity and more rebound adjuster control.
Dave what viscosity fork oil you suggest for marzocchi rac 50 on gsxr1000 ?
@@vr___46 I would use 5w fork oil on precision equipment like the RAC 50
What is the difference between fork oil and fork fluid? Maxima has two of them so which one should i choose? (my bike has 31mm telescopic forks)
Both have the same properties chemically. Fork fluid is generally used for racing. Are you racing? If not, fork oil.
@@CatalystReactionSBW Well I am definitely commuting not racing... Thanks for your explanation...
Buy my manufacturing didn't mentioned the viscosity grade for my Aprilia sr150 scooter....so I'm confused 🤔
That would be 10w or 15w grade fork oil.