simba

Wow Thanks for all the Help guys!!!! I agree that i will try the stock VFR 0.85 springs before I go buy a set of Ohlins 0.90 units.(not very hard to change after) The next purchase will have to be the Racetech valves, weather they are from Racetech or from Jamie (would love to give him a lil extra $ for some baseline shim stacks) im not sure yet. Forks are apart and working on sandblasting/ repainting the lower legs. In regards to the rear shock, I have no issue with making some custom adapter for my wall mounted automotive spring compressor to remove the spring and I have talked with a few locals that will recharge the shock for a reasonable cost. Again would love to buy the valves from Jamie, Its clear now that i have a game plan I should get in touch with him and is wisdom! Will prolly do the forks first but will look at the rear shock shortly after. Thanks again for the help guys!

If memory serves, these bikes all have a clevis as lower shock mounting point and a significantly lower linkage ratio than the VFR with correspondingly (much) lower spring rates. These will require some serious mods to be usable. Older CBR 600 F and CBR 900/929/954 were more similar to the VFR but the V4 architecture and the LBS/ABS plumbing also puts physical space at a premium so even these do not fit all that well. DMr offer the CBR F4 shock for the 6G and the 929 for the 5G. They are the best fit but they still require mods to get the proper length and access to the adjusters may not be all that great, especially preload on the 6G/F4 swap. This is what i suspected about the newer bikes. I will be pulling all the linked braking and associated brackets. Is the 929 shock preferred if it can be made to fit? I have herd there is a special wrench that makes the f4i preload more feasible. Not sure what you mean by 'some results' from RT. At your weight, RT recommend a 17.8 kg/mm spring for the 6G. To 'calculate' spring rate you need to have some pretty accurate figures for sprung weight, weight distribution and, most importantly, linkage ratio. These are not very easy to come by and the linkage ratio is a VFR peculiarity (significantly higher leverage than most anything else on the market these days). If you used another bike on the RT calculator and input the VFR's weight, that might give you acceptable results for the forks but the shock will likely be way off. That seems unlikely. Check your sag, adjust your preload accordingly and play with the damping adjuster a bit. The (admittedly pretty rubbish) stock shock is softly sprung but can be adjusted very hard, especially at your weight. I'm over 210 w/o gear and it kicks like a mule if I give it too much preload and turn the adjuster near full hard. Ahh i must have been using the wrong calculator when I was crunching some numbers. Makes me wish I could go try more suspension settings, (damm snow!) as I haven't gotten this bike to turn at low speed as I would like. So 0.90 springs for the front and 17.8 for the rear. Would the stock 0.85 vfr springs work in the F4i forks? Any suggestions on re-valving either the forks or the rear shock? Thanks for replying RC36!

Hi there Guys, Looking to get into the nitty gritty with the suspension on my 2004 VFR800. I mostly ride on the street (rough Canadian roads) with 1 -2 track days a year. Due to my size and weight (5'8" and 135lbs) I find that the bike is actually over-sprung in the rear and takes alot of commanding to turn at low speeds. I also wanted to add some more adjustability to the front forks as they seem under valved( harsh) So far I have purchased a set of F4 or F4i forks (cannot tell due to being very similar but could be .66kg or .77 kg springs) along with a very good condition set of 4 pot calipers. These will need to be re-sprung! but I'm unsure as the best way to do the calculations for the increase, (race-tech shows vfr800 with my weight should be .86 kg springs, but when using vfr weight on the CBR600F4i calculator it recommends .95 kg springs( seems too stiff) If the .86 is the correct calculation is it possible to use the VFR800 springs in the F4 forks? (using the preload spacer to accommodate for slight length variations) Also Any recommendations about Valves? Racetech? Ohlins? DIY??( I have herd of polishing the pistons and making your own stacks but dont know the science) I would also contemplate sending the valves to DM for upgrade( forks are currently disassembled) My next questions relate to the rear shock, My expectations is that the F4i rear shock will also be the replacement for the VFR stocker. Are there any higher performance shocks that could be fitted the the VFR? 600RR 1000RR GSXR1000? or do all these newer designs have fitment issues? If i am to use the F4 rear shock as the best inexpensive starting point Again what is the best way to calculate spring rate, some results from Racetech show the stock 14.3 kg unit as acceptable for my weight, other times it says its too much????? Once a spring is chosen, what should be done for valves? Racetech?, diy?, send to DM? Open to any suggestions or ideas to improve the ride and performance! Thanks in Advanced!

Wow looks great!!! What parts are you using ? CBR? Tristan