Shock oil for 1997 YZ 250

[Rcannon]

I am so new to this bike that I have not decided if the suspension needs to be modified or not. I have worked on shocks a little bit and nitrogen is no problem.

In your opinions, what oil should I use in my shock. At this point I am basically looking for a stock replacemant oil. Thank You!!!

 

[shockdoc]

Torco & Spectro light have been my favs.



doc

 

[Rcannon]

You guys, please dont beat me for this. Is there any diffwerence between 5 wt. fork oil and 5 weight shock oil? My brain says no, but my wallet is scared to try and prove this.

 

[Jeff Howe]

Your brain is wrong this time. In most cases shock oil will be devoid of some of the polymers that fork oil has to prevent foaming. With the shock under pressure it doesn't need a big dose of anti foam additives. Shock fluid will also have a higher VI (viscosity index) rating which helps prevent fade at extreme temps. Forks don't get near as hot as a shock does. One thing about most shock oils is that possibly some of them are using VI improver (polymers again) to jump the VI ratings. Polymers generally shorten fluid life and thats not really good either. This is why some advertise the fact their fluids contain no polymers. But that comes at a price too.

 

[marcusgunby]

Not disagreing with shocknut here but a weird thing the Honda manual says is to use fork oil.Now i do this but i choose them wisely.Motul make a very good quality oil thats has a high VI but the easiest to find seems to be Silkolene Pro RSF-it comes in serveral weights and has a very high VI- around 450 i think.If you decide to use a good quality fork oil i would serive it more regular than if you used a top quality shock oil.I would only go half as long on fork oil.Now my shock never stays the same for more than a month so it isnt a problem for me but most dont want this kind of hassle.Race tech sell a high quality shock oil but it costs alot but you are saving on labour so it offsets it.

 

[Rcannon]

Shocknut, and everyone, thanks for this info. The only oil I ever bothered to look at was marketed by Honda. It was marked Showa fork/shock oil.

How can this one oil possibly be good for both?

Looking closer at my shock, I can see that the peening has been drilled out. I imagine this means the previous owner changed the oil.

 

[marcusgunby]

If showa say it works then i bet it does-i prefer a proper shock oil but it matters less if you are not a very fast rider.

 

[Jeremy Wilkey]

How about Desiel fuel........ LOL We actually mixed it for some ice racing bikes that where riding in ultra cold condtions.... :eek:

 

[Rcannon]

Jeremy, thats just what I was looking for. Still, why follow the advise of an expert? I am going to use some of the unscented heating lamp oil. That diesel fuel smells bad!

By the way, did it work?

 

[Jeremy Wilkey]

You know, knowig what I've been learning it makes me scared to think of the things I try now not knowing what I'm soon to learn...


But tacking it all around, It worked flawlessly... But you would never hear me say that on the record.. I guess I close enough to my DRN crew to speak candidly..

BR,
Jer

 

[NO HAND]

...One thing about most shock oils is that possibly some of them are using VI improver (polymers again) to jump the VI ratings. Polymers generally shorten fluid life and thats not really good either. This is why some advertise the fact their fluids contain no polymers. But that comes at a price too.

Still looking for that brand that advertises "contains no polymer". Haven't found it anywhere. :confused:

 

[marcusgunby]

Contact jeff(shocknut) directly for some top oils-i know he has some special brews:)

 

[NO HAND]

Thanks Marcus, I would suspect Shocknut is referring to Motorex. I did a long search of many posts and found some of his later posts ...wouldn't use anything but M1 or Motorex.

 

[marcusgunby]

Im sure he makes his own -but it would cost too much to get it sent over to you-i think most of the top bands are safe to use-i try to stick to one brand as much as possible to eliminate variables.Lets not forget alot of riders go 2 seasons or more on the std snot oil that comes in new bikes-many of them never feel any thing wrong with the suspension even though the oil is like water.

its like our sub tank conversation-you can go too deep very easy:)

for a ama pro its super important-for a weekend racer a good oil will suffice.

 

[bclapham]

i am glad this topic has come up. i am looking for oils right now- i can get good prices on Motorex and Maxima. the motorex stuff is listed as "racing fork oil" are you guys using it in shocks as well? alternatively, maxima make three types, "racing shock oil", "racing fork oil" and just "fork oil".

in an ideal world, i am just looking for one fluid that will work in both shocks and forks at a reasonable price- so i would like to go motorex- let me know if it will work, or if there are any other oils available in the US that would work- i dont really want to pay more than $5 a liter though! :cool:

 

[terry hay]

Bruce I have been very pleased with the results I've had with Motorex. Good value for money and great performance.
Terry

 

[NO HAND]

...std snot oil that comes in new bikes...

lol, you know what? it's what it smells like too :)


Bruce, glad you chimed in. I saw an old post where you also asked about Motorex, but the thread got no answer. I was thinking of bringing it back to life. The axact title of the post was: Racetech goldvalves freek wanted

It says in their promo that it is really meant to be used for both shock and fork. They say it got the anti foaming for the fork and the high vi index to keep the shock happy. What caught my attention is they say this oil is meant to last longer. Perhaps this is their way of saying they didn't go too crazy on polymers.

Hi Terry, I have also heard good things about Torco and Spectro. How does it compare? I haven't tried Torco but spectro was leaving much deposits and took long to clean. It wasn't the synthetic blend though, the mineral one 5w. It was a while ago. I suppose their synthetic blend now is also better at keeping things clean. My main concern was shock fade. It always take a lap or two before the shock wakes up but then at the end of say 10 laps it starts to change again. M1 atf I tought was good in forks. But took some time to warm up in the shock, maybe a lap before it felt normal.

 

[terry hay]

No Hand
I used Spectro for a couple of years when I first started into suspension and was happy with the performance, but then, I hadn't spent a lot of time experimenting with other brands. Once my supplier change product lines I began to try Belray, Silkolene, Motul. The Belray seemed about the same as the Spectro but the others were a little nicer to work with. Then I tried the Motorex and was totally impressed with the product. I have been using Motorex for quite a few years now and use it as my bench mark. I am prepared to change brands if something better comes along. I just haven't found it yet.
Terry

 

[Rcannon]

This thread actually started so long ago I have again changed the oil in my shock. I ended up changing to Golden Spectro shock oil after I asked this question. More out of dumb luck than anything else.
I felt like this oil held up reasonably well to a season of abuse. I had virtually zero time this year to trailride. The 25 documenteed rides were to the track.


The old oil looked fairly clean when I dumped it out. It was slightly dark, but nothing compared to the stock oil that was dumped last year. Thanks to all you guys for your help. These two silly oil changes would have cost me at least 200.00 locally! I was freaked out about adding precisley the correct psi of nitrogen. The low volume makes verifying the pressure impossible with a normal guage. I paid the local shop, who shall go nameless, to add it. I peaked through the door as he was doing this. He turned the regulator on the tank up to @ 175 and let it rip. I am no expert, but I freaking well know I could have dont that!

By the way, I think Terry Hay Rules. I like his no BS attitude in the posts.

 

[NO HAND]

...By the way, I think Terry Hay Rules. I like his no BS attitude in the posts.

dito :thumb:


I sent an email to Motorex to have their specs; viscosity index, pour point etc. I'm anxioux to see what is the viscosity index. I've been also told (in the vendors connection forum) their 5w is a little bit thicker than regular 5., it is about 7.5w. There is a consesnsu for it being a very good fork oil. It seems to be more complicated for the shock. I'm surprised because the motorex web site says it is for both; if you read the fine print. Perhaps some people are hesitant because the name on the bottle says "racing fork oil". I don't know what to think. I hope its good also in the shock because I'm gonna try it. Just ordered some 2.5w and some 5w. I received advices to use 2.5w in the fork inner chamber, and probably will use Mobil1 atf in the outer chamber. I onmly have to figure out what weight to use in the shock. I would lean toward the 2.5w too. Well I have some time to think about it because there is 3 feet of snow outside :uh:

 

[Jeff Howe]

The VI is right around 200. It can be used in a shock, I've done it but it's not the ideal shock oil but I've seen worse (stock pops in mind right away, the stuff is horrid garbage). I don't remember off hand now all the other oils I did comparsion testing with but the Motorex was the best fork oil of them all. It has been my goal all along to model my own fluids after their product. I wanted to improve on one aspect of it and that was to have it remain cleaner.

For somebody to say the Motorex 5 wt is a 7.5 wt is lame. The only thing they can base that on is other brand fluids viscosity and who is to say that brand would be the perfect 5wt? Honestly, using "wt" designation for suspension fluids is not a really good way to categorize them but it's what most people seem to understand best. All it really tells you is the 2.5 is lighter then the 5. The viscosities vary so much by brand it's not even funny.

As far as "no polymers" go it was Race Tech that makes this claim. I need to read their description again because it is pretty much impossible to not have any at all. The thing is to have the fluid properties you want without resorting to adding in large amounts of it. It is my guess they mostly mean they are achieving their VI numbers without resorting to large amounts of VI improver (which is a polymer additive). Shock oil with big numbers on the VI usually have alot of VI improver in it and lots fo fork oils have a lot of anti-foam agent packed in them. From what I understand these large amounts tend to shorten fluid life.

Some have said the RT Ultra Slick oil is just rebadged Motorex with dye added to it for color and an expensive label tacked on. I don't know this for a fact. It might be, it might not. Whatever, if they can sell it for $25/qt with their name on it more power to them. I do know you can't make a really good fluid for really cheap. I've tried it and it is not possible to get the numbers you want out of it but I know full well you can make a really good oil for a lot less then $25/qt retail.

 

[bclapham]

Jeff: one word answer please :)

ive got a set of showas on my rm and a set of kyb on my yz.

if i get the motorex, which one will cover all applications ie fork and shock on both bikes, the 2.5 or the 5wt???

(i am thinking the 2.5)

thanks- ps- no more chemistry today- i do all that stuff mon-fri and its my day off today! :) :eek: :joke:

 

[Jeff Howe]

well on your off day use the 2.5 wt. When your on try the 5. :)

just kidding around, sorry Brucie, I'll catch the next flight to Bolivia.

2.5 is fine Bruce.

 

[bclapham]

Thanks Jeff! :thumb:

 

[terry hay]

Bruce
Given that the inner chamber affects damping and the outer chamber affects airspring effect and bottom out cone, it is feasable to run different oil weights. You can actually tune the effectiveness of your bottom out system by varying your oil weight in the outer chamber without affecting the air spring. Pretty cool huh!
Terry