marid2apterbilt

Sam, I don't see how it would be possible to Not use the F4/F4i cartridge and expect to have any rebound adjustment as the length of the rebound rod is specific to the length of the cartridge. If you used the longer VFR cartridge the adjusting rod end(needle part) would be no where near the valve orifice it's trying to regulate! You dont need the f4cartridge itself as it is too short to work properly with the VFR upper and lower fork tubes, You do need to use the VFR cartridge with F4/F4I internals inside it.. .. The Adj rod, and hollow rebound rod with rebound valve on the end is all. Well you need the fork cap too.. And yes it does work.. The F4 adj rod end (needle part) is specific to the rebound rod itself(Hollow tube w/ rebound valve on 1 end and bolts to the fork cap on the other) If you use the F4 cylinder cartridge in the VFR forks the rebound valve actually tops out on the cartridge itself instead of the built in stops inside the forks. And will also pulll the Comp valve thru the bottom of the cartridge destroying the C-Clip that holds it inside the cartridge.. not sure if Im right but I refer to the cartridge as the long -+1" tube that the rebound valve rides inside of.. ..

This is also my big question right now. I have the F3 iterials (thanks SEB !) just no racetech valves You will REUSE the F3rebound valve atttached to the Rebound adjustment rod.. I did this with a 6th gen and F4 parts. So. F3 interials whit F3 rebound valve and VFR compression valve and VFR spring, and outer upper and lower tubs. Got it right? Check the length on the F3 cartridge itself. THe only parts I used for my F4/6thgen conversion were the rebound rod and attached rebound valve. I tried using the F4 cartridge but it was too short and didnt let the forks extend fully.. Remember I did this with F4 parts not F3 on a 6th gen but I assume it shoudl be about the same either way.. I also had to reshim the rebound valve but that is a whole other subject..

This is also my big question right now. I have the F3 iterials (thanks SEB !) just no racetech valves You will REUSE the F3rebound valve atttached to the Rebound adjustment rod.. I did this with a 6th gen and F4 parts.

This is Interesting, Wanna make several adapters ?

A hand pump vacumn bleeder for brakes works well also, I have the Correct tool now but the first time I just Zip tied the hose of a brake bleeder to a Bent clothes hanger and hung it on the side of the fork, Works well. If you oops and fill the fork to the top once you get the fluid flowing to the cup hold it below the level of the forks, remove top off of the cup and let it drain back into the bottle, Walla your done.. There are probably 100 ways to get the same results..

I have Not made it out to the shop yet! :dry: This work was done prior to my crash! :fing02: I've never had an issue removing the bottom fork bolt as long as I keep the fork fully assembled and us a Impact wrench! :blush: A Impact wrench is the biggest key factor here for removal, A little pressure from the forks being intact allows the quick Banging action of the Impact to work.. Like lightly holding a wrench on a bolt while using a Impact, You dont need much...

Yes it can happen... The best protection is to leave it in the crate.. A simple tip over in the garage can total a VFR.. Check a parts fisch for the right or left side parts + a Radiator and a front nose fairing. If any of these are craccked its replaced.. If your unlucky enough as I was that something is near by to dent your tank also its definately up to and over 2-3000.00 damage .. Brake pedal, rearset, rear fairing, front fairing, left or right side fairing, Radiator, Bar end/Grip/Or Clipon, Brake/Clutch lever, headlight, Gas tank, Exhaust Can...................... All these can easily be damaged in a simple tip over.....

Sorry if I helped to the :laugh: But I do agree with you except for the setpoint for it to come on.. 6Krpm is 6K no matter what gear your in the vacumn at closed throttle will be the same. you could easily use a EGR valve off a car, attaching the switch to the exhaust gas bypass pin and using a vacumn line from just about anywhere on the motor to activate it.. Im not sure if they sell Adj vacumn swithches but a EGR valve should be easy to come by in a junk yard ($5 ?) and should already be somewhere close to the vacumn pressure you will need. Others might know more about the best way to do this or in your research..

Really? I have never hear of that before? I imagine it works over the rear tire - but does it work over the rear tire than..say if you are just using front and back brakes at the same time? I tend to ride in a style that is suited to the "pace" that is not so much brake and more or less off throttle before the turn, engine braking I suppose then on the gas as soon as I have set my lean angle as soon as possible. I am not a knee dragger either so I am not blazing into turns so fast either. I rarely use my rear Brake, Mostly fronts only, @ hirevs and engine braking will eat a rear tire quickly, I have noticed this mainly on twisty roads like the gap. You can literallly Eat up a rear tire in no time engine braking when railing the twisties. @ 9 or 10000 rpms you might as well be standing on the rear brake pedal if your in 2nd or 3rd gear Closed throttle... Lower gearing has even more effect.. Almost like locking up the rear tire.. take my word for it Dont go fully closed throttle in 3rd gear 13000 rms, you wont like the feeling of the rear tire trying to slide around onn you..

http://www.satoracing.com/

Not to mention heavy engine braking really eats up tires fast..

VFR800R.... Raising the rear will Quicken turn in some, Effects of doing this too much will induce Instability/Head Shake/ Tank slappers. The little bit that the Adjuster for the chain would raise the bike will not raise it to the pint of being unstable, Other factors would have to be added to this.. So what is the final ration of a 17 tooth front ?

Reshimmed the stock valves today but I have kinda hit a wall so to speak.. 1 fork when compressed and the adj rod turned all the way to full hard shows that it is working as you can see it returns rather slowly. The other fork seems a little stiffer on the return but nowhere near like the first. I have torn this fork down 3 times and put it back together but cant seem to find the problem.. I am more than positive that the shim stacks on both are identical, Checked them with a digital caliper twice.. Im stumped.....

The comp seem fine its the Rebound that I really woould like to adjust some... Pm sent..

A few more questions for thoswe with more knowledge than I.. BR, Seb, JD and any others.. BR.. In a linked post you went to a .95kg front and 19kg rear springs.. Would my 1.0kg front and 18kg rear setup (per racetech) cause handling issues with the front, Reccomendations ? The front does like to slip at the exit of a turn while on the Gas, Usually when coming out of a Knee dragging angle.. SEB and Jamie.. or who ever else.. I recently found some info that detailed the teardown of OEM valves, As I have not done this to any of mine yet this is still basically theroretical.. I also found a site that sells Suspension valve shims. http://mx-tech.com/?id=products&cat=12 My theory is to add a few Shims to the Rebound stack only. But with no experience I have no idea where to start with size or how many... Also after 4 hrs of Google pages I couldnt find any info on where to start with shim sizes etc... even ttried to find a shim stack calculator but couldnt find one... Can anyonne reccomend a Shim stack configuration using Oem valves and 10wt oil and 1.0 Kg front springs ?

Qouted from first post..

Thanks BR... Working on getting it sorted out the last little bit. The Comp side IMHO feels fine as is, It is the little Bumps that the rebound side is having a issue with (sounds like Enzed-Viffer's issue) It is almost like a out of balance tire bouncing. But at lower than Hiway speeds.. No more big shake your head type of bouncing as before but a lot of little bitty bounces.. If that makees any sense.. Gonna take a look at a set of valves in pieces and see and or try 15wt oil first.. I may buck up and get a set of racetech valves but for now I dont have the cash.. Jamie D.... I think the key to your experience in your post is that your revalving the forks (I assume Racetech valves) Which from the many posts I have seen on revalve setups with racetech valves take much lower wt oils by design.. Enzed... Thanks for the info.... I added the 1.o kg springs some time ago (I weigh 225lbs) It didnt seem tooo bad at this setup with stock oil but on ocassion it would feeel bouncy on some rough roads, Currently it feels better, Not too stiff.. The bouncy feeling Im having now feel like very small rises in pavement but you cant see the changes in the pavement. Best way to describe is a Out of balance tire, But instead of it bouncing at Hiway speeds its usually below 70mph, Actually backwards from a out of balance tire.. Before this rebound adj project I was thinking of using 15 wt oil with the stock Reb/Comp valves and my 1.0 springs.. It almost seems too soft on the valving.. I havve also considered .95 springs but Im gonna play with it a bit before I go that route.. The 1.0kg springs feel really good at my weight, Not too harsh or too soft. Im a good sized person at 225lbs and 6' 4".. Geared up I weigh 238lbs.. Damn I wish I was home most wknds like everyone else, It wouuldnt take me so long to get it all sorted out then

Yeps thats what I said , Did, and posted above aside from the fork oil.. Every thing I have found leads to stock oil being 10wt. Are you sure it is 5wt ? Also several in this thread mentioned that 7 and 5wt oil was to light when they completed this mod. A very well seasoned Local mechanic sugested I try 15wt after taking a test ride with the current 10wt oil i put in there.. I upgraded the springs last year, Front and rear.. 1.0 fronts and 18kg rear..

Ok I finally got all the parts sorted that I needed and a few mods along the way.. First off the parts you will need from a Honda CBR F4/F4I.. Fork Cap Rebound valve and adj/connector rod. Yes that is all you need, you dont need the F4 Catridge tube, Just everything associated with the F4 rebound.. Disassemble the VFR cartridge removing the dampening rod with attached Reb valve, Insert F4 dampening Rod with attached Reb Valve and reassemble. Important Notes.... I highly reccomend cutting a new spacer for the spring 1/4 to 1/2" longer than you need. When complete you will only have about 1/4 of preload Adjustment Or Less IF YOU DON"T DO THIS.. As one of my earlier worries of the rebound valve topping out, That is a NON- ISSUE.. With 10wt oil and 1.0kg front springs the F4 valve still isnt stiff enough with the adjuster all tthe way in.. I reccomend addding 1-3 shims to the valve if possible.. I plan to research this soon.. Or use 15wt Fork oil.. I think the First would be better. This is also a sugestion from Ken Wheeler, I took the bike to him this morning to get it dialed in. He made a few adjustments to the front and rear and noted that he didnt like the feel from the rear being so high. Alsso If I lower the rear some this will help with my problems with the front.. It rides much smoother now in the rear also since his adjustments.. So I will be tearing it all apart again this winter or early spring.. My overall view of the F4 Rebound fork Mod.. So far it is somewhat of a Improvement as I still have a few issues to address with its function. It feels much better than before at High speeds and soaks up major road hazards very well.. I took it over cracked pavement and couldnt feel a single bump, Even hit a piece of tire at 70mph and barely felt it.. At low speeds its still a bit bouncy/POGOey. So a few minor changes will have to be made as I noted above. Further refinement shouldnt cost much (Fork Oil) so Im going to guess a total cost of around 225.00 - 250.00 (Price includes New Sonic springs)(assuming you find the F4 parts for around 100.00) for a compliant front end.. Add in a set of RaceTech valves for 400.00 for a total of 625.00 and you will have a very compliant setup with Adjustable Rebound..

You should have about 1" or a bit more of preload spacing from the top of the fork tube to the bottom of the cap before assembly. And never reuse any fluid for anything! Its also the best insurance to have clean new fluid going back in what ever you have taken apart. .02 Im bbeginning to wonder if anyone has even read this thread.. Yes Im going to use New fluid.. Due to using F4 internals the 1" may not apply.. The F4 forks are shorter than VFR forks and Im mixing the components of both to gain rebound Adjustment in the OEM VFR forks....

In theory and I wish I had this thought before.. Also its gonne be 3 weeks tilll I can comfirm.. I just not OCD with a tape measure, But I will play with the functionality of something till im satisfied its RIGHT.. You should be able to just use the Reb valve and comp Rod in the Vfr cartridge. The Rod/Reb valve is gonna top out regardless I assume. and I may have to build a litle preload into the Spacer length when I put them together for the final time.. I had to buy some more 1" Electricl schd 40 pvc so I have a 10ft piece at the house to play with.. Hopefully someeone who did this mod will eventually stop in n post..

Reason Im asking is the F4I cartridge is too short to be able to apply preload.. Adj the preload once they are together just lengthens the fork tubes.. The parts Fiche shows a similar aluminum spacer for the F4 as the one in the bottom of the VFr forks. Guess I will tear them apart again when I get home and measure the cartridge tubes, If it is the case that the vFR tubes are longer I will use those.. The extra length from the VFR cartridges will help keep the fork length a little closer.. and may be that little extra that is needed.. VFR Capt Bob.. No Im not rushing it. I never get in a hurry, I just had to leave midday to go back on the road.. I knew I didnt have time to finish. Unfortunately Im not home everynite like most people so I cant just walk into the garage and do what ever.. I also knew I didnt have the fork oil or guage.. I will finish it some time when I get baclk again.. Until then I have plenty of time to ponder on the situation or order things I may need for the project.. My problem is the longer I have to think about it the more O.C.D. kicks in. But I have never forgot to tighten a nut or bolt.. I always check 2 or 3 times to make sure all nuts and bolts are in or tight.. real pita when your replacing a engine or rebuilding a tranny.. As for the Race tEch Instructions.. There are no Racetech parts being used..