F4i forks - Wrist Twisters
 
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post #1 of 13 Old 12-06-2013, 02:57 PM Thread Starter
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F4i forks

Looking for a set of F4i forks. Let me know what you have.

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post #2 of 13 Old 12-06-2013, 03:29 PM
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I have a set, PM me for details.

2012 Yamaha Super Tenere
2001 Honda Blackbird
2007 Honda 919



49/50 visited on two wheels. 1 more to go!
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post #3 of 13 Old 12-06-2013, 03:53 PM
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What is it that makes the F4i forks better? Better pistons or more adjustability?

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post #4 of 13 Old 12-06-2013, 06:00 PM
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The cartridges are better.
They have more adjustability.
They are a better platform to use if one is going to do a full build .

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post #5 of 13 Old 12-06-2013, 06:07 PM
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Quote:
Originally Posted by mcromo44 View Post
The cartridges are better.
They have more adjustability.
They are a better platform to use if one is going to do a full build .
they are very similar to the 04+ 919 forks with the addition of the compression adjustment.

if your on a 02-03 stock forked bike they are a worthwhile upgrade.... 04+ eh if you really want em go for it... either way (f4i or stock forks) you are going to be respringing them.

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post #6 of 13 Old 12-06-2013, 06:16 PM
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Quote:
Originally Posted by mcromo44 View Post
The cartridges are better.
They have more adjustability.
They are a better platform to use if one is going to do a full build .
So they have an adjustment for low speed compression?

I would like to bet my hands on another pair of stock forks and play with the carts.

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post #7 of 13 Old 12-06-2013, 09:41 PM
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Quote:
Originally Posted by NZspokes View Post
So they have an adjustment for low speed compression?

I would like to bet my hands on another pair of stock forks and play with the carts.

Not sure if the adjusters for rebound (04 919 forks) / compression (f4i) are low speed or high speed..

I think they are just a general compression / rebound setting, a middle grounds of sorts. i know going from full fast (soft) to full slow (hard) on the rebound on my 04 919 forks makes a BIG change

Just what ever you do... play on the faster (softer) side of rebound... as you dont want the forks to pack out mid turn leaving you without suspension.

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post #8 of 13 Old 12-06-2013, 11:25 PM
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Yeah they will be low speed bleeds for adjustment. Shim stack will be controlling it for the most part.

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post #9 of 13 Old 12-07-2013, 10:30 AM
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Quote:
Originally Posted by NZspokes View Post
Yeah they will be low speed bleeds for adjustment. Shim stack will be controlling it for the most part.
Correct.
But also a good time to repeat that "speed" is in terms of fork travel, not the road speed.
Top adjuster is for rebound.
The one down low on the fork leg is for compression, F4i forks that is, seeing as no 919 ever came with compression adjustment.
IF one is contemplating a F4i fork conversion and intends to do lots of track days and do some level of chassis tuning, do yourself a favour and get a pair of Traxxion compression adjuster needles to change out the Showa items. The Traxxion units are less than $ 50, super easy to fit without having to take the forks apart, and provide much better adjustment tuning capability.

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post #10 of 13 Old 12-07-2013, 10:50 AM
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Quote:
Originally Posted by mcromo44 View Post
Correct.
But also a good time to repeat that "speed" is in terms of fork travel, not the road speed.
Top adjuster is for rebound.
The one down low on the fork leg is for compression, F4i forks that is, seeing as no 919 ever came with compression adjustment.
IF one is contemplating a F4i fork conversion and intends to do lots of track days and do some level of chassis tuning, do yourself a favour and get a pair of Traxxion compression adjuster needles to change out the Showa items. The Traxxion units are less than $ 50, super easy to fit without having to take the forks apart, and provide much better adjustment tuning capability.
So you want the low speed bleed to help with fork dive under brakes? What does the Traxxion needle achieve?

I would love to get my hands on some stock pistons to see if they can be modified for more flow. Then just copy some of the custom stacks for the F4i forks.

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post #11 of 13 Old 12-07-2013, 11:00 AM
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Quote:
Originally Posted by NZspokes View Post
So you want the low speed bleed to help with fork dive under brakes? What does the Traxxion needle achieve?

I would love to get my hands on some stock pistons to see if they can be modified for more flow. Then just copy some of the custom stacks for the F4i forks.
The low speed compression is intended towards road surface indulation tuning, just like the low speed rebound is, both being low velocity chassis reactions to non bump road inputs.
It's a fairly fine tuning aid.
The Traxxion item is still a broad enough spectrum needle to allow for mixed use while still getting decent fine control.
Other needles exist that are narrower band in terms of range of control, but with finer adjustment.
Dial in the screw enough to take away brake dive, and you will have far excessive damping for road input energy.
Frankly, a 919 properly sprung with 125 mm of oil height that has a front brake savvy rider at the controls, is not going to bottom out the forks, even hauling down hard from top end to end up down 3 gears or more.
You can get some anti-dive benefit by using the compression needle, but that is a very secondary intention of the low speed compression adjuster.

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post #12 of 13 Old 12-07-2013, 11:20 AM
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Quote:
Originally Posted by NZspokes View Post

I would love to get my hands on some stock pistons to see if they can be modified for more flow. Then just copy some of the custom stacks for the F4i forks.
Our basement is a disaster zone so it's not practical for me to fish about to see if I can find the stock 919 and F4i valve sets that I think I still have.
So failing that, I'll say this.
Just keep in mind that there are two approaches to overall damping curve shaping.
Traxxion and RaceTech both use high flow valves and derive all their curve shape from the shim stack build.
Ohlins uses valves deliberately configured to provide some of the shaping, the rest of it coming from the stack. LDH is the guy to ask about the details of this, not me, that's for sure.
Showa I'm not sure about, but if I was to guess, I'd say some valve shaping.
Keep in mind that if you gut the valve for more flow area, you could end up with inadequate flange area for the shim stack to be able to properly seat and seal against.

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post #13 of 13 Old 12-07-2013, 11:54 AM
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I will try to find some here, bit far to send bits like that.

Yes any mods to a stock piston would have to allow for sealing of the shims or there is no point. It would just create a orifice damper. But a higher flow stock piston would have to help the fork as it does seem to hydro lock a little over stutter bumps.

I would also have thought just using the F4I comp damper in the stock cart would work.

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