Originally Posted by kellymac530
Thanks for the input folks.
I already own the YZ forks and even though KTM forks are not too bad priced, I have been scouring ebay for a while, the cheapest I have seen is about $200.00 USD for a set with triple clamps. I own the YZ forks and the TCs. I LOVE KYB forks. Enzo is not far and they are awesome at KYB stuff and have always valved all of my YZ race bikes. I have looked and researched springs and unless I am missing something, Progressive makes up to 79kg/inch springs for these forks and stock is 48kg....I think that will be plenty if I keep the bike as light as I want to. Especially is Ross' boys at Enzo valve me the way they have in the past, I will be fine. But food for thought for sure.
You might be totally right, and Enzo is a fantastic tuner for sure. I have KYB closed chamber forks on my 2012 Husky and they are simply fabulous. I don't want to give the impression that they are subpar forks, I love them. I too had KYBs off a YZ450 and was trying to get some help from James at Superplush. He was very helpful and talked me out of it for a couple reasons.
First was the springs. He seemed to think (and maybe he was wrong) that there were simply no options past a certain weight which I can't remember. We even thought about cutting the stock springs to increase the rate at the expense of travel but this was quickly scrapped.
The other issue you really need to think hard about is total weight of the bike. This is not to be taken lightly. KYB forks were designed for 250# motocross bikes and while they might fair perfectly well with your proposed bike donor, the braking is simply not up to par. I went round and round with this issue. Standard motocross bikes have a ~260mm thin lightweight rotor and 2 piston calipers. That won't slow a heavy bike down enough to be safe in my opinion. Sure you can upgrade everything to supermoto and run a 320 rotor and caliper relocation bracket, but now the weak link is the caliper. Plus price all that stuff out at Motostrano and you'll see what I mean. Plus the front wheels have very thin spokes to save weight. you don't want that if you are running this setup on an boxer, they weigh too much. So now you need a heavy spoke kit etc.
After weeks of kicking it around I realized it would be cheaper and better just to spend the money now on a set of KTM 950 forks, brakes, rotors, and a new front wheel from Woody's than upgrade lightweight stuff that wasn't up to the task from the start. Yes, it's expensive to do it right I know but it's even more expensive to do it wrong, then right. I would ask Enzo to have a look at your setup and get their opinion. I think you are probably right you can get heavier springs but the braking issue is the one that would give me pause.
On the FZ1 I have a stock KTM 950 setup, twin rotors, twin Brembos etc, heavier springs. All stock parts
Bike weighs about 450, maybe 475#
On the CBR, I have KTM dirt bike forks, 320 Braking rotor, Braking master and Braking caliper which are all supermoto caliber stuff. Bike weighs 364# ready to ride. I am swapping out all of this to my new bike and running the factory KTM supermoto components which utilize a 310mm rotor and a 4 piston radial caliper
The New Ninja I am going to rob all those components. The bike is yet to be built but will be very close to 375-400 by the time I am done. I think this is really the limit for dirt bike components on a bigger conversion, as i tip the scales at 230 myself.
I would just encourage you to look into all the variations with your build, and some you won't realize until you get there. I made many mistakes on my first couple builds, now that I am on my third I am trying hard to not repeat them. Most of the mistakes were from trying hard to make something work that was simply not the right tool for the job. I'd waste valuable shop time and money fighting it the whole time and finally buy the right part and bam, fixed. Shoulda just done it right the first time.
Many different ways to get to the end result and building a bike is highly personalized so I don't want to try and force my way of thinking on your build. I'm just commenting from someone who has been to the other side a few times the lessons learned I would hope to save you from making the same mistakes.