CBR F3 forks with blue spot calipers on a firestorm.

[ConTRo13R]

The latest turn of my firestorm project has led me to fork upgrade options. From research i found the CBR F3 have stiffer stock springs that the VTR does but much worse brakes... 2 pot sliding calipers. The forks from the CBR are however longer but not by enough to foul any of the fairings i dont think, I will need to work out how much of the cbr fork i need coming about the triples once i get to fitting.

The CBR forks are also 41mm and the set i have acquired had recently had the seals and oil changed, this allows me to also have a 6 spoke wheel (the CBR F3 wheel will also fit in the VTR forks, same axle and spacers) and stiffer springs.. all that is left is to find a solution to the braking.

This is where i have had a guy cut me some brackets that will fit R1/R6 blue spot calipers to the castings on the CBR F3 forks and will line up with the CBR discs.

I haven't seen this mod done anywhere else so seemingly quite a unique new one for a 'storm you can follow the build thus far on my instagram @henryjrea

[tony.mon]

So why do you want stiffer springs?

[Stephan]

CBR F3 forks are popular upgrade on other bikes because of good compression valving, but springs are still not stiff enough (not considering actual shape and age). According to Racetech site, 95-96 has 0.71, 97 0.699, and you need at least 0.8, or 0.85 is popular "universal" spring rate.

I believe you can just change cartridges on fork bottoms, so brake mounts will stay ...

[ConTRo13R]

.85 is what your looking at for track work. I doubt im going to be doing alot if any track work. The VTR springs are about .599 i think so the .71 seems to be a midway point between the two.

The forks are very similiar that i think you can just swap the cartridges but im not 100% on that.. besides how many firestorms have you seen with Yamaha blue spot calipers

[popkat]

CBR F3 forks are popular upgrade on other bikes because of good compression valving, but springs are still not stiff enough (not considering actual shape and age). According to Racetech site, 95-96 has 0.71, 97 0.699, and you need at least 0.8, or 0.85 is popular "universal" spring rate.

I believe you can just change cartridges on fork bottoms, so brake mounts will stay ...

CBR F3 fork do Not have compression damping, in fact they offer absolutely nothing to a VTR they are pretty much the same fork with different caliper mounts, only reason to fit them is if you've crashed your bike and can't find any VTR forks

.

[popkat]

.85 is what your looking at for track work. I doubt im going to be doing alot if any track work. The VTR springs are about .599 i think so the .71 seems to be a midway point between the two.

The forks are very similiar that i think you can just swap the cartridges but im not 100% on that.. besides how many firestorms have you seen with Yamaha blue spot calipers

0.85 is not a specific spring for track work but they do work on track, but they work just as well on the road, don't know where you get your info from but it's wrong.


If you want blue spots just put them on the standard forks, your gaining nothing by fitting CBR600 forks, see post above also.


.

[ConTRo13R]

Iv already said they are pretty much the same fork, i am also aware there is no compression damping setting.. having them in my hands.. the compression valving on cbr f3 forks is very good though and thats not just my own thoughts. Im making no comparison or statements.. i dont think your really reading this thread????

Basically i want stiffer springs.. but not so stiff il have an uncomfortable ride on the road. I also know that spring rate is tied to rider weight and that stiffer springs are better for track work with heavy braking and harsher contact with the ground.

I wish you luck trying to fit R1 calipers to the stock forks

Its a mod that i can do and will make my bike unique but also has no negatives...so why not.

[Ckennedy]

I don't doubt that modding is fun and each to there own but if all you wanted were stiffer springs why not fit stiffer springs to standard forks and then get brackets made up for the calipers to fit standard forks like your having to do with the car forks? Or have I missed something in your posts?

Sent from my SM-G920F using Tapatalk

[Stephan]

If you are about 75-80 kg, 0.85 spring is just right for street. For race 0.875 or 0.9 absolute max. There is not so much difference in correct rate between road and track.

And take into account that you buy forks over 10 years old, springs can be pretty worn. Have you measured it?

[ConTRo13R]

I don't doubt that modding is fun and each to there own but if all you wanted were stiffer springs why not fit stiffer springs to standard forks and then get brackets made up for the calipers to fit standard forks like your having to do with the car forks? Or have I missed something in your posts?

Sent from my SM-G920F using Tapatalk

For the most part this is free for me as i have the parts already. Stiffer springs is just a benefit above the stock springs. Iv used the cbr forks before on another bike and they are great compared to my vtr ones. And they have recently been refreshed (seals and oil)

Who doesnt like yamaha blue spot brakes, they are so sharp.

Do springs really wear out, as in collapse a bit?

[Ckennedy]

You'll find the gap between the springs can shrink so become weaker/less effective. Certainly worth measuring.

Got to be worth looking at doing if it's nearly free to do.

Never tried yam brakes but I'll stick to my radial Brembo's

Sent from my SM-G920F using Tapatalk

[popkat]

Iv already said they are pretty much the same fork, i am also aware there is no compression damping setting.. having them in my hands.. the compression valving on cbr f3 forks is very good though and thats not just my own thoughts. Im making no comparison or statements.. i dont think your really reading this thread????

Basically i want stiffer springs.. but not so stiff il have an uncomfortable ride on the road. I also know that spring rate is tied to rider weight and that stiffer springs are better for track work with heavy braking and harsher contact with the ground.

I wish you luck trying to fit R1 calipers to the stock forks

Its a mod that i can do and will make my bike unique but also has no negatives...so why not.

Your info is wrong and your trying to spread that shite on here, fortunately most round here are clued up enough to know better !
If you want your forks right then listen, if not go ahead and fit the CBR forks that have "very good compression damping" what a load of crap.


CBR600, lighter bike, different geometry. The CBR fork was ok for it's original application but they were soft, heavier springs and different oil makes a difference (same as on VTR), I've run the same springs and oil level in a CBR and a VTR the only difference between the two was the weight of the oil and there probably wasn't too much in that. ATF or 5wt in the CBR, 10wt in the VTR.


It's your bike so do what you want with it, but still you are gaining nothing fitting them... as for the Blue spots, they're so last year these days


.

[ConTRo13R]

Im not spreading 'shite' all i have said is the fork springs are stiffer, they are 41mm and i think the compresion is good. Search all over the web and you will see the vtr forks suck, there is a reason why many people choose the cbr f3 forks in there bikes.

As for the lighter bike different geometry argument surely the same can be said for any usd conversion... do you get upset about these too? There is only a 2kg difference between the two bikes both with a full tank, 207kg cbr and 209kg for the vtr.

I'm fully aware that nothing compares to new 'weight rated' springs and oil...this costs money.. my change is free which is another reason for 'why not?'

This thread isnt about telling people the next best thing to do is what im doing, its a thread showing what im doing and for the enjoyment of others to see/comment or critique. I can see no negative from doing this, only benefits, i get the brakes i like and think will look good, i also have something unique that no other 'storm has (which is what modding is all about), and i get a slightly stiffer spring. That all mounts up to a win win for me. If i get a months down the road and decide to re spring my forks, so be it but for now i just cant see this being a none worthwhile task?

Idealistically some 43mm yokes and a CBR F4 front end with full adjustments would be incredible.. but i haven't the money

[lloydie]

Im not spreading 'shite' all i have said is the fork springs are stiffer, they are 41mm and i think the compresion is good. Search all over the web and you will see the vtr forks suck, there is a reason why many people choose the cbr f3 forks in there bikes.

As for the lighter bike different geometry argument surely the same can be said for any usd conversion... do you get upset about these too? There is only a 2kg difference between the two bikes both with a full tank, 207kg cbr and 209kg for the vtr.

I'm fully aware that nothing compares to new 'weight rated' springs and oil...this costs money.. my change is free which is another reason for 'why not?'

This thread isnt about telling people the next best thing to do is what im doing, its a thread showing what im doing and for the enjoyment of others to see/comment or critique. I can see no negative from doing this, only benefits, i get the brakes i like and think will look good, i also have something unique that no other 'storm has (which is what modding is all about), and i get a slightly stiffer spring. That all mounts up to a win win for me. If i get a months down the road and decide to re spring my forks, so be it but for now i just cant see this being a none worthwhile task?

Idealistically some 43mm yokes and a CBR F4 front end with full adjustments would be incredible.. but i haven't the money

I've just picked up cbr f4 forks and yokes for £50 [FACE WITH STUCK-OUT TONGUE AND WINKING EYE]

[Kev L]

Good luck with your mods matey, hope they work out for you.
Popkat is a motorcycle dealer/mechanic/successful racer so is coming at your mods from a more engineering based response, but as he says, it's your bike, you do what you like