Fork Revalve vs. Drop-in Cartridges

[betoney]

I have the Forks-By-Matt (Pattonme) upgraded cartridges in my 2015 forks, both legs are activated with rebound and compression pistons and rebound adjustment caps. I have the rebound adjusted where they feel best but discovered that is on the last click fully closed- clockwise. I would prefer not being maxed out in case I want to adjust further at some point. 

The question is, if I'm going to spend the money to get a revalve to modify the rebound circuit, would it be worth the additional cost to get drop-in cartridges? Compression adjustment on the fork cap would be nice as well.
Has anyone changed from a piston kit on stock cartridge to custom built cartridges? Was there a difference in feel, enough to justify the cost? 

This Fall I will be due for the 2nd 2-year suspension service and would have any modifications done at that time while the forks are torn apart.

 

[piotrek]

If the maxed out rebound screw is the real issue, and you can live with the compression screw as is, then just dump  the oil and replace with something a bit heavier (higher CSt@40C). Do that before servicing the rest of it. Make sure to note the original oil level. Lift the outer tube slowly all the way up to empty the outer chamber into the inner tube, then measure. If the new oil works well... then replace the seals, bushings, refill etc... and save cash. Oil can make a big difference. It is super easy work. I am assuming you have all the specs of the original build from Matt? If you really, really want the comp screw in the cap though... this might turn into a regret in a hurry.

If you're not doing the service yourself... do you already have a quote for the work (with, and without the re-valve)?

Edited May 31, 2020 by piotrek

[StealthAu]

If it is due for a service, does it need changing?

 

[betoney]

41 minutes ago, piotrek said:

If the maxed out rebound screw is the real issue, and you can live with the compression screw as is, then just dump  the oil and replace with something a bit heavier (higher CSt@40C). Do that before servicing the rest of it. Make sure to note the original oil level. Lift the outer tube slowly all the way up to empty the outer chamber into the inner tube, then measure. If the new oil works well... then replace the seals, bushings, refill etc... and save cash. Oil can make a big difference. It is super easy work. I am assuming you have all the specs of the original build from Matt? If you really, really want the comp screw in the cap though... this might turn into a regret in a hurry.

If you're not doing the service yourself... do you already have a quote for the work (with, and without the re-valve)?

I was out on a ride experimenting with different clicker settings and realized that the rebound settings were on the last available click.  I have considered a slightly heavier oil but wondered how that would affect the high speed compression- pot holes and harsh road imperfections.  If I'm not mistaken...(???) the compression adjustment controls the slow speed movement???  To be honest I haven't consulted a suspension shop about this yet since its the weekend.  I have the specialty tools to do a basic fork oil or spring change myself but I don't want to chase one issue and create another.

To be honest, I'm not sure what Matt used to modify the stock forks, considering the extremely low price I'm fairly certain he didn't install Gold Valves or any other aftermarket manufacturers piston kit, was it modified oem parts?.  Fork cartridges modified with rebound and compression pistons in each leg + new springs + rebound fork cap for 2nd leg + packaging and shipping across the country for less than $500.  Even though they work well, curiosity has me wondering, could they be improved?  could they be really, REALLY improved? 

[duhs10]

1 hour ago, piotrek said:

Lift the outer tube slowly all the way up to empty the outer chamber into the inner tube, then measure.

I'm confused by this statement... I was under the impression that you measure fork oil level with forks fully compressed (ie. outer tube as low as possible on the inner tube)

[piotrek]

5 minutes ago, duhs10 said:

I'm confused by this statement... I was under the impression that you measure fork oil level with forks fully compressed (ie. outer tube as low as possible on the inner tube)

I was describing the process for determining the oil level in a fork that's been in use. Fill the tube to say 140mm, go ride the bike for a week and measure again... it will not read 140mm.

Some oil will flow back and forth between the inner tube and the space between the inner and outer tubes as you ride the bike. Our inner tube has overflow holes near the top, so by raising the outer tube we are forcing the overflow oil back into the inner tube. Then collapse the outer tube and measure the level as normal.

i do this even on new fill, just to make sure I have all the oil where it needs to be before I measure.

[piotrek]

1 hour ago, betoney said:

I have considered a slightly heavier oil but wondered how that would affect the high speed compression- pot holes and harsh road imperfections.

Depends on the range of adjustment that you have on the compression valve. That's what it's there for... if the oil is a bit too heavy... back off the screw to compensate a bit. If the harshness goes away... you're done, and if not... you get your wish. 😉

1 hour ago, betoney said:

Even though they work well, curiosity has me wondering, could they be improved?  could they be really, REALLY improved?

It was a $500 mod... I am sure it can be improved with a $1,300 set of fully adjustable cartridges. Comes down to cost-benefit thing really... and very subjective.

[betoney]

6 minutes ago, piotrek said:

Depends on the range of adjustment that you have on the compression valve. That's what it's there for... if the oil is a bit too heavy... back off the screw to compensate a bit. If the harshness goes away... you're done, and if not... you get your wish. 😉

 

What I am saying though is, the compression damping screw adjusts low speed compression while the high speed (non-adjustable) is affected by valving restrictions or oil viscosity.  If I change to a higher viscosity oil to compensate for the rebound, - I believe - that the high speed compression will suffer, thicker oil resulting in harshness.  Is this correct or am I thinking wrong?

[piotrek]

37 minutes ago, betoney said:

What I am saying though is, the compression damping screw adjusts low speed compression while the high speed (non-adjustable) is affected by valving restrictions or oil viscosity.  If I change to a higher viscosity oil to compensate for the rebound, - I believe - that the high speed compression will suffer, thicker oil resulting in harshness.  Is this correct or am I thinking wrong?

Sorry... didn't catch that. You're right, it will be affected... but you never know by how much until you try it. Going slightly heavier with the oil might buy you another click or two in the rebound circuit, and not affect the compression damping to a point where you're unhappy with it. I guess the whole point is... if I were in your shoes, I'd explore how I could inexpensively fix what I have before spending big money... but I know... the force... it is strong. 🙂

Something else to consider... your rebound circuit might come back to its former glory with just new/fresh oil (same viscosity). Two years of hard riding will affect its properties.

Edited June 1, 2020 by piotrek

[duhs10]

6 hours ago, piotrek said:

I was describing the process for determining the oil level in a fork that's been in use. Fill the tube to say 140mm, go ride the bike for a week and measure again... it will not read 140mm.

Some oil will flow back and forth between the inner tube and the space between the inner and outer tubes as you ride the bike. Our inner tube has overflow holes near the top, so by raising the outer tube we are forcing the overflow oil back into the inner tube. Then collapse the outer tube and measure the level as normal.

i do this even on new fill, just to make sure I have all the oil where it needs to be before I measure.

I got you... Thanks for the explanation.

[2and3cylinders]

Are you sure you adjusted the rebound rod seat contact when you assembled the fork cap?  It is a very delicate and precise setting. I have the same set up from Matt and have enough rebound.  What fluid did you use, has rebound changed?  Maybe a dump, flush and refill with slightly heavier fluid will restore performance.  Are there signs of slider wear, stiction?  What weight springs do you have compared to you weight , sag, ride height, etc.?

Ride safe!

 

 

 

[betoney]

5 hours ago, 2and3cylinders said:

Are you sure you adjusted the rebound rod seat contact when you assembled the fork cap?  It is a very delicate and precise setting. I have the same set up from Matt and have enough rebound.  What fluid did you use, has rebound changed?  Maybe a dump, flush and refill with slightly heavier fluid will restore performance.  Are there signs of slider wear, stiction?  What weight springs do you have compared to you weight , sag, ride height, etc.?

Ride safe!

 

 

 

Nothing has changed with the forks since the last time they were serviced, November 2018.  The fluid and seals have about 18k miles since then and are scheduled for the next service at the end of this season. 

I was asking around on the FZ09 forum as well and the rebound rod was mentioned just like you suggested, so that is something to look at. 

Like I had mentioned, the forks currently work well, I was out for a ride experimenting with different setting when I discovered that both legs were on the very last click.  That is where I originally started thinking- If I had them disassembled for a service and possible revalve, would it be a worthwhile 'upgrade' to get a set of drop-in cartridges?

Thanks for the help

[quaxum]

Hi, did you change the springs when you did the "cart" upgrade previously?

My take on this is you should service the forks and get the correct weight springs if it was not previously done, since you already have the compression/rebound and preload adjustments. That is basically a cartridge.

my 2cents hope this helps.

[betoney]

14 minutes ago, quaxum said:

Hi, did you change the springs when you did the "cart" upgrade previously?

My take on this is you should service the forks and get the correct weight springs if it was not previously done, since you already have the compression/rebound and preload adjustments. That is basically a cartridge.

my 2cents hope this helps.

Yes, in the the price breakdown listed above, springs were part of the package. 

[2and3cylinders]

What price breakdown?

if your over 190 in ATGATT your springs should be .90 or even .95, and Matt would have set the washer stack, compression bottom bolt office (be should have provided a fixed and adjustable compression bolt, my adjustable bolt''s needle net's O-ring kept leaking) and porting accordingly. I believe Matt recommended 16 cst @ 40C. Now I'll have to check my rebound to verify how much I have, I recall 8 clicks are available.  Again, a refresh with slightly heavier fluid before full disassembly is recommended given you have adjustable compression.