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potatochips

Forks by Matt Review

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potatochips
Getting the forks done (cartridge retrofit) was easy and painless.  Matt was very helpful, great communication.  Turnaround was fast, contact him when you're ready, he'll give you the estimate of turnaround time.  
 
I originally bought the bike on my way to Barber, took it for a quick street ride and loaded up.  With the stock suspension, the bike did better than i expected, but the suspension was really lacking.  It was tough to push it, the suspension was easily overwhelmed.  Granted, I weigh 210+ geared up, the stock springs alone weren't up to it, scraping pegs was easy.
 
In addition to the forks being redone, I also added an Ohlins shock.  I can really push the pace now and the bike feels pretty stable, didn't scrape pegs once, probably more due to realizing I need to get off this bike more than sportbikes.  I can't give you a more descriptive review, not an expert, I just know the bike feels great now.  Even on the street, the bike felt much more planted and stable.
 
A little confession, I didn't even set the sag on the forks, or touch any adjustments, I'll have to talk to Matt to see what he recommends for sag.  I planned to adjust them between sessions, but the tire wear looked spot on.  I did make adjustments to the rebound damping on the shock.  On my other bikes, I'd usually set the sag, and basic adjustments as Dave Moss (see link below) would, then adjust the rebound damping based on tire wear.  Trackday orgs usually have suspension gurus that you can pay to setup your bike, and they always seem to go by techniques Dave Moss uses.  I bought his videos 5 years back, not sure what the deal is now, I've seen parts of them free here and there.
 
http://feelthetrack.com/
 
A little background, I've been riding 20 years, liter bike, 600's, motard, even a Virago 250, great cheap college beater.
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pattonme
Depending on what tires you have mounted, pull the fork up 10mm and maybe as much as 20 (do it 5mm increments past initial 10mm). It's a shame the Ohlins doesn't come with adjustable ride-height. also set fork preload to arrive at 40-45mm rider sag.
 
If you can put enough stress in the (front) tire I guess you can tune rebound that way. Me, I recommend the 'shove' test to get close (a little extra 'hop' at the end is ok) and then ride it and see how the bike behaves from 1/3 corner entry (trail braking done) to the exit. See if it'll hold the line etc.
 

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potatochips
When I installed them, I put them about 10mm above, I'll try more. The shove test with a little extra hop is how Dave Moss recommends as well, as do all the tuners I've seen at tracks.  And thank you, awesome work!
 
Ran 003RS tires, though I may go to DOT's or slicks if I can find wheels.  I have a spare set of wheels for my first gen R6, I'm going to see what it will take to make them work.

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gregjet
" I have a spare set of wheels for my first gen R6, I'm going to see what it will take to make them work." Very very interested to here how that goes.
 
 
OK finally got a chance to get out on my Matt fork cartridges. Now I have found I had not got the GVE's close enough ( later information on settings was unavailable when I installed them) but had swapped them out for Matt's cartridges. After some confusion on fork fluid I refilled them and reset the valves to the recommended settings ( Matt's recs) . The front end is now very well behaved. Still some fine tuning to do but lack the road/track to push to find the holes in the performance accurately. Big difference is the front now tracks over bumps and undulations with feel but not harshness. VERY pleased.
 
 
 

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twotone
" I have a spare set of wheels for my first gen R6, I'm going to see what it will take to make them work." Very very interested to here how that goes. 
 
OK finally got a chance to get out on my Matt fork cartridges. Now I have found I had not got the GVE's close enough ( later information on settings was unavailable when I installed them) but had swapped them out for Matt's cartridges. After some confusion on fork fluid I refilled them and reset the valves to the recommended settings ( Matt's recs) . The front end is now very well behaved. Still some fine tuning to do but lack the road/track to push to find the holes in the performance accurately. Big difference is the front now tracks over bumps and undulations with feel but not harshness. VERY pleased.
 
 

 
 
Are they SFF yet?
Or you have to remove axle to adjust compression?
If the latter it is possible to drill axle to reach adjusters see post with pics in the other thread.

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gregjet
SFF??
Axle has to be removed for comp. adj.
Personally wouldn't drill axle for the road bike. May consider it if it was a track bike that I used at more than one track.
 

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pattonme
SFF = single-function fork. ie. all the latest (typically Big-Piston) arrangement where all adjustments can be made from the caps; nee Andreani and Matris.
 
Convenience is nice @twotone, but like I've pointed out on the Matris and Andreani threads, doing it with a 20mm system is not easy and the 2 examples out there did it rather poorly.
 
I am looking at trying to do velocity-dependent damping. but it's mostly done on shocks where the fluid displacement is modest. On forks, one I'm having trouble modeling it, and two at 20mm piston sizes it's gonna be impossible I think.
 
 
 

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pattonme
The more traditional way is to have a "tower of Hanoi" shim stack arrangement on a traditional flat-top piston. That I can model easily.
 
This is the 'Penske way' where the slow speed shim sit on the outer ledge, and the highspeed sits recessed. The problem is in forks we need those big orifices to go wide-open which implies this arrangement simple doesn't work except in shocks.
 
Proposed fork piston.
https://dl.dropboxusercontent.com/u/180639/20mm%202-stage%20mid.jpg
 
Their example:
http://shop.penskeshocks.com/images/D/vdp%20explanation%201-01.jpg

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twotone
SFF?? Axle has to be removed for comp. adj.
Personally wouldn't drill axle for the road bike. May consider it if it was a track bike that I used at more than one track.

 
 
Don't worry it's been done in hollow axles by manufacturers, I've owned two Showa equipped with such,
The convenience is undeniable.
Otherwise SSF is the way to go

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twotone
SFF = single-function fork. ie. all the latest (typically Big-Piston) arrangement where all adjustments can be made from the caps; nee Andreani and Matris. 
Convenience is nice @twotone, but like I've pointed out on the Matris and Andreani threads, doing it with a 20mm system is not easy and the 2 examples out there did it rather poorly.
 
I am looking at trying to do velocity-dependent damping. but it's mostly done on shocks where the fluid displacement is modest. On forks, one I'm having trouble modeling it, and two at 20mm piston sizes it's gonna be impossible I think.
 
 

 
 
Keep at it you'll get there,
 
TD, Anrea' Matris, Yamaha ( R1, FZ1) marzzochi and many others have done it, if they are flawed in some way then it's a matter of a fix somewhere depending on internal design and shims etc

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gregjet
Design for lower viscosity? That way the holes will effectively be bigger and less restrictive. ( yes I know you know that, it for others following the conversation who may not). 2.5 weight oil will flow substantially easier than 10 or even 5. We have the advantage of starting from a relatively high viscosity for road bikes ( unlike dirt USD's).
The tandem valving , I admit I haven't thought it through properly, but it's one of those design things that sticks in the back of your mind telling me that there is an answer here.
Same with the idea of using port shaping to restrict the flow at high speed flow rather than valves.
 

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twotone
15-20 cSt is a good target, however big port Pistons respond well to higher visc, while smaller ports to lower visc. But it does come down to shim design.
 
LE' s founder now passed away, was a genius who could turn stock parts into winning bikes
And sometimes whip name brand suspended bikes.
 
Interestingly Maxton, does 1 leg valving on bikes with such as stock to save time and money and avoid
Damage with separating axle clamps from staunchions. They work very well.

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norwest
LE' s founder now passed away, was a genius who could turn stock parts into winning bikes And sometimes whip name brand suspended bikes.
Ed Sorbo is no slouch either. 

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