Evo fork oil - Page 3

crawsue · 21-10-2024, 02:46 PM

Been rereading some threads including this one re the Evo Marzocchi forks , although I had mine “K-teched “ a couple of years ago I still feel that they are too firm, the invoice for the work is showing that they used “HPSF -017 “ in the rebuild. I notice in this thread that someone is running SAE 5 …..Unfortunately our technical sage Vince has stopped contributing at the moment, has anyone any experience in this field ? Regards Crawsue.

Dukedesmo · 21-10-2024, 03:59 PM

My Monster forks are 916 Showa units which I took to Ktech for valve kit & re-spring as the springs from the 916 were too firm due to the Monster being a lighter bike.

Ktech used 5w oil in them (they also used 5w in my 916 Ohlins) when they did the job, IIRC they said because it makes them smoother/more progressive?

They work nicely but I found that they would bottom out under extreme braking. I asked Ktech and they advised to add an extra 5 or 10ml of oil to each leg. I did and this solved the bottoming out.

So I guess the oil and the quantity can be used to alter the way the forks work however, if they're just too firm then maybe you need lighter springs?

crawsue · Today, 01:28 PM

Unfortunately K-tech only supply springs down to 8.5…which should be spot on for my dressed weight…..can anyone confirm that the HPSF -017 specification is in fact SAE 17 ? It seems an arbitrary spec/ number….?

Mr Gazza · Today, 03:26 PM

I just googled HPSF -017 and that specific oil didn't come up but it does seem that the number after HPSF (high performance suspension fluid.) doesn't bear any relationship with the viscosity. So I doubt it is 17w.
I did note that they go down as low as 2.5w and maybe lower, so you shouldn't have any trouble finding a lighter oil.
Best people to ask is going to be K-Tech.

Regarding the "firmness" of your forks. Have you tried adjusting the damping? if indeed you have adjustable damping?

Darren at MCT actually put thicker than standard oil in mine (15W I think) And that certainly made the adjustments more vivid than previously.
I backed off the compression a couple of clicks to make it more comfortable over the Norfolk B-roads and likewise the rebound.
That made it worse and so I called Darren and he said always do more to the rebound than compression. So I backed off the rebound a couple more clicks and that did the trick, it's been fine ever since.
Just wondered if it just needs a little play? Note your current setting before you adjust though.

Edit.. Just found this. https://www.propowermx.co.uk/product...EaApHCEALw_wcB
Looks like you already have 5w?

21-10-2024, 02:46 PM	#31
crawsue Bronze Member Join Date: Nov 2016 Location: Glasgow Bike: M1100evo Posts: 274	Evo fork oil. Been rereading some threads including this one re the Evo Marzocchi forks , although I had mine “K-teched “ a couple of years ago I still feel that they are too firm, the invoice for the work is showing that they used “HPSF -017 “ in the rebuild. I notice in this thread that someone is running SAE 5 …..Unfortunately our technical sage Vince has stopped contributing at the moment, has anyone any experience in this field ? Regards Crawsue.

21-10-2024, 03:59 PM	#32
Dukedesmo Registered User Join Date: Sep 2010 Location: Leics Bike: M900 Posts: 2,893	My Monster forks are 916 Showa units which I took to Ktech for valve kit & re-spring as the springs from the 916 were too firm due to the Monster being a lighter bike. Ktech used 5w oil in them (they also used 5w in my 916 Ohlins) when they did the job, IIRC they said because it makes them smoother/more progressive? They work nicely but I found that they would bottom out under extreme braking. I asked Ktech and they advised to add an extra 5 or 10ml of oil to each leg. I did and this solved the bottoming out. So I guess the oil and the quantity can be used to alter the way the forks work however, if they're just too firm then maybe you need lighter springs? __________________ M900, 916, LeMans II.

Today, 03:26 PM	#34
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,956	I just googled HPSF -017 and that specific oil didn't come up but it does seem that the number after HPSF (high performance suspension fluid.) doesn't bear any relationship with the viscosity. So I doubt it is 17w. I did note that they go down as low as 2.5w and maybe lower, so you shouldn't have any trouble finding a lighter oil. Best people to ask is going to be K-Tech. Regarding the "firmness" of your forks. Have you tried adjusting the damping? if indeed you have adjustable damping? Darren at MCT actually put thicker than standard oil in mine (15W I think) And that certainly made the adjustments more vivid than previously. I backed off the compression a couple of clicks to make it more comfortable over the Norfolk B-roads and likewise the rebound. That made it worse and so I called Darren and he said always do more to the rebound than compression. So I backed off the rebound a couple more clicks and that did the trick, it's been fine ever since. Just wondered if it just needs a little play? Note your current setting before you adjust though. Edit.. Just found this. https://www.propowermx.co.uk/product...EaApHCEALw_wcB Looks like you already have 5w? __________________ Last edited by Mr Gazza; Today at 03:34 PM..

Today, 01:28 PM	#33
crawsue Bronze Member Join Date: Nov 2016 Location: Glasgow Bike: M1100evo Posts: 274	Unfortunately K-tech only supply springs down to 8.5…which should be spot on for my dressed weight…..can anyone confirm that the HPSF -017 specification is in fact SAE 17 ? It seems an arbitrary spec/ number….?